The Fourth Amendment in a Digital World

Georgetown University Law Center Georgetown University Law Center

Scholarship @ GEORGETOWN LAW Scholarship @ GEORGETOWN LAW

2017

The Fourth Amendment in a Digital World The Fourth Amendment in a Digital World

Laura K. Donohue

Georgetown University Law Center

, lkdonohue@law.georgetown.edu

This paper can be downloaded free of charge from:

https://scholarship.law.georgetown.edu/facpub/1791

http://ssrn.com/abstract=2836647

71 N.Y.U. Ann. Surv. Am. L. 533-685 (2017)

This open-access article is brought to you by the Georgetown Law Library. Posted with permission of the author.

Follow this and additional works at: https://scholarship.law.georgetown.edu/facpub

Part of the Fourth Amendment Commons, Privacy Law Commons, and the Science and Technology Law

Commons

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THE FOURTH AMENDMENT IN A

DIGITAL WORLD

LAURA K. DONOHUE*

I. Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 554

II. Literal Reading of the Text . . . . . . . . . . . . . . . . . . . . . . . . . . 560

A. Houses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 561

B. Papers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 568

C. Voice Communications . . . . . . . . . . . . . . . . . . . . . . . . . . 573

III. Private versus Public Space . . . . . . . . . . . . . . . . . . . . . . . . . . 581

A. Open Fields, Naked Eye . . . . . . . . . . . . . . . . . . . . . . . . . 582

B. Aerial Surveillance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 589

C. Radio-frequency Enabled Transmitters . . . . . . . . . . . 594

D. Global Positioning System Technology . . . . . . . . . . . 599

E. Enhanced Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 609

F. Technological Challenges to the Private/Public

Distinction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 612

1. Digital Tracking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 613

2. Recording and Analysis: Informants and the

First Amendment . . . . . . . . . . . . . . . . . . . . . . . . . . . . 631

IV. Personal Information versus Third-Party Data . . . . . . . . 640

A. Information Entrusted to Others . . . . . . . . . . . . . . . . 641

B. Digital Dependence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 647

V. Content versus Non-Content . . . . . . . . . . . . . . . . . . . . . . . . . 650

A. Electronic Communications . . . . . . . . . . . . . . . . . . . . . 651

B. Pen Register/Trap and Trace Devices . . . . . . . . . . . 658

C. Envelope Information . . . . . . . . . . . . . . . . . . . . . . . . . . . 661

VI. Domestic versus International . . . . . . . . . . . . . . . . . . . . . . . 664

A. Law Enforcement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 666

B. Foreign Intelligence Collection . . . . . . . . . . . . . . . . . . 668

C. Technological Challenges to the Domestic/

International Distinction . . . . . . . . . . . . . . . . . . . . . . . . . 674

VII. Confronting the Digital World . . . . . . . . . . . . . . . . . . . . . . . 678

* Professor of Law, Georgetown Law; Director, Georgetown Center on Law

and National Security; Director, Georgetown Center on Privacy & Technology.

Thanks to Joel Brenner, Allegra McLeod, Matthew Waxman, and participants in

the Georgetown Law Faculty Workshop for their comments on an earlier version

of this Article. I also am grateful to Jeremy McCabe, who provided invaluable help

in securing many of the cases, laws, texts, and papers cited in this Article.

553

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554 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

INTRODUCTION

Fourth Amendment doctrine no longer reflects how the world

works. Technology has propelled us into a new era. Traits unique to

a digital world are breaking down the distinctions on which the

Court has traditionally relied to protect individual privacy.

What are these characteristics? Digital information is ubiqui-

tous. Individuals cannot go about their daily lives without generat-

ing a footprint of nearly everything they do. The resulting data is

accessible, recordable, and analyzable. And because it is digital, it

can be combined with myriad sources, yielding deeper insight into

our lives. Data is also non-terrestrial and borderless. Bits and bytes

populate an alternative world. They may be held on a server, but

their generation, transfer, and availability are not tied to territory,

undermining doctrines that rely on three-dimensional space. Tech-

nology, moreover, embodies an efficiency drive. Innovation makes

it possible to do more, and to do it better, faster, and cheaper than

before. So more information is being captured, even as the re-

source expenditures required steadily decline. Simultaneously digi-

tal interfaces are rapidly proliferating, replacing traditional modes

of interaction. This means that new types of information are availa-

ble, even as our ability to conduct our daily lives has become heavily

dependent on technology. It has become a non-option to eschew

the digital world, if one wants to live in the modern age.

These characteristics undermine the distinctions that mark

Fourth Amendment doctrine. Consider, for instance, the diremp-

tion between private and public space. The Court has long relied

upon this dichotomy to determine what constitutes a reasonable ex-

pectation of privacy.

It draws a line at the walls of the home, citing

the risk assumed by individuals when they go out into public and

expressing a reluctance to disadvantage law enforcement by forcing

them to turn off their natural senses or to ignore what any ordinary

person could ascertain.

The amount and types of information available in the public

sphere, however, have exponentially increased. WiFi and Bluetooth

signals can be collected, global positioning systems and vessel moni-

toring systems operated, and radio frequency identification chips

tracked. Automated license plate readers record the time, date, and

1. See, e.g., Brief of James Otis, Paxton’s Case (Mass. Sup. Ct. 24–26 Feb.

1761); Part II(A), infra. Cf. Raleigh, Opinion, 3

ASSACHUSETTS

, Apr. 29, 1773,

at 1, cols. 1–2 (discussing the problems with royal officers seizing traders’ property

without “proper cause”).

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 555

location of cars, while network data reveals where mobile devices

travel day and night. International mobile-subscriber identity-catch-

ers pinpoint the devices located in a given area. Internet protocol

databases, in turn, register users’ locations. Financial transactions

and credit card records place people in certain places at certain

times, while cameras, enhanced with remote biometric identifica-

tion, may be mounted on vehicles, poles, buildings, or unmanned

aerial systems, creating the potential for 24-hour monitoring, seven

days a week, ad infinitum.

The digitization of this information means that it can be re-

corded and combined with biographic information and subjected

to algorithmic analyses, penetrating further into citizens’ lives. Even

when data is derived from the public sphere, the government’s use

of it may impact free speech, the right to assemble, and religious

freedom, to say nothing of personal privacy.

Technology erodes other Fourth Amendment distinctions. A

series of cases in the 1970s established the contours of what would

be considered “reasonable,” based on who holds the information.

Data held by the individual generating it is afforded a higher level

of protection, while data held by third parties, such as companies

with whom one contracts for goods or services, is granted a lower

level of protection. But technology has created an imbalance. Digi-

tal dependence—i.e., the degree to which we rely on digitization to

live our daily lives—has radically changed the world in which we

live.

School, work, social interactions, hobbies, and other pursuits

are now online by nature of how society functions. This has two

implications. First, new kinds of information are now generated

and, therefore, accessible. Second, our reliance on industry and

third-party providers to service the needs of daily life has made

much more of our personal information, as well as new kinds of

personal data, vulnerable to government collection.

2. For discussion of facial recognition technologies and remote biometric

identification, see Laura K. Donohue, Technological Leap, Statutory Gap, and Constitu-

tional Abyss: Remote Biometric Identification Comes of Age, 97

INN

. L. R

. 407

(2012);

U.S. G

’

CCOUNTABILITY

FFICE

, GAO–15–621,

ACIAL

ECOGNITION

ECHNOL-

OGY

: C

OMMERCIAL

SES

, P

RIVACY

SSUES

AND

PPLICABLE

EDERAL

(2015); Mark

Pomerleau, A Closer Look at Facial Recognition, GCN (Aug. 7, 2015), https://

gcn.com/articles/2015/08/07/facial-recognition.aspx.

3. For a thoughtful, early discussion about the increasing centrality of digitiza-

tion, see generally

ANIEL

J. S

OLOVE

, T

IGITAL

ERSON

(2004).

4. Amazon Echo, for instance, can hear what one is saying from across a

crowded room. Alyssa Newcomb, How Amazon Echo Can Hear What You’re Saying

from Across the Room,

ABC N

EWS

(Nov. 6, 2014, 4:01 PM), http://abcnews.go.com/

Technology/amazon-echo-hear-room/story?id=26740479. Samsung’s own privacy

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556 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

Another distinction centered on the type of information under

consideration—content versus non-content—similarly collapses in

the contemporary world. For years, envelope information has been

considered non-content, and thus less protected than content, on

the grounds that the latter, and not the former, reveals an individ-

ual’s private communications, thoughts, and beliefs. But what hap-

pens when a search engine reveals what it is that is being examined

in the uniform resource locator (URL) itself?

Metadata of all sorts

can reveal much about an individual

—indeed, law enforcement

regularly uses search terms to bring criminal charges against indi-

viduals. The reason is simple: patterns in phone calls, text messages,

instant messaging, emails, or even URL visits demonstrate beliefs,

relationships, and social networks—yet the form of that data

(metadata) has not historically been considered content. The same

is true of consumer metadata and financial records. Sophisticated

pattern analytics mean that non-content morphs into content, mak-

ing any formal distinction meaningless.

policy for its smart televisions warns consumers that anything discussed in the

proximity can be “captured and transmitted to a third party.” Alyssa Newcomb,

Samsung Privacy Policy: Watch What You Say Around Your Smart TV,

ABC N

EWS

(Feb.

9, 2015, 9:29 AM), http://abcnews.go.com/Technology/samsung-privacy-policy-

watch-smart-tv/story?id=28829387. Their televisions use facial recognition and bio-

metric identification technologies to track family members’ actions, expressions,

and utterances. See id.; Samsung Privacy Policy – SmartTV Supplement, http://

www.samsung.com/sg/info/privacy/smarttv.html (last visited Oct. 29, 2016). Toys

inside the home similarly record private conversations. Although Fourth Amend-

ment doctrine draws a line at the curtilage of the home, extending higher protec-

tions to what happens indoors, it simultaneously divests third party data of any

privacy interest. Fourth Amendment doctrine has yet to address the tension.

5. If I were, for instance, to search for “Molotov cocktail” on Amazon.com,

the URL that comes up is https://www.amazon.com/s/ref=NB_sb_noss_1?url=

search-alias%3Daps&field-keywords=Molotov_cocktail. Subject-specific sites simi-

larly indicate the content, with Wikipedia’s URL reading https://

en.wikipedia.org/wiki/Molotov_cocktail.

6. See generally Laura K. Donohue, Bulk Metadata Collection: Statutory and Consti-

tutional Considerations, 37

ARV

. J. L. & P

. P

’

757 (2014) [hereinafter Dono-

hue, Bulk Metadata] (discussing privacy issues regarding the NSA’s bulk collection

of telephony metadata);

AURA

K. D

ONOHUE

, T

UTURE OF

OREIGN

NTELLI-

GENCE

39–53 (2016) [hereinafter

ONOHUE

, F

UTURE

]. A helpful definition of

“metadata” offered by Anne J. Gilliland is “the sum total of what one can say about

any information object at any level of aggregation.” An “information object,” in

turn, “is a digital item or group of items, regardless of type or format, that can be

addressed or manipulated as a single object by a computer.” Anne J. Gilliland,

Setting the Stage, in

NTRODUCTION TO

ETADATA

, p.2 (Murtha Baca ed., 2d ed.

2008).

7. See, e.g., Swati Agarwal et al., Open Source Social Media Analytics for Intelligence

and Security Informatics Applications, in

ATA

NALYTICS

: 4

NTERNATIONAL

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 557

Differentiating between domestic and international communi-

cations similarly proves inapposite to the contemporary world.

Communications are now global. If I email a friend from a restau-

rant in Boston and she reads the email while sitting at a restaurant

in New York, the message may well have gone internationally, plac-

ing it under weaker Fourth Amendment standards.

It is not that

the privacy interest in the communication is any different than that

of a traditional letter. It is simply that digitization and the advent of

worldwide communications networks have narrowed my right to pri-

vacy for the same information. Or how about cloud computing, or the

use of Drop Box, or Google Docs? Is all of this information fair

game, so to speak, just because Google happens to hold the docu-

ment in Singapore as opposed to San Francisco? The problem, as

with the distinctions between private and public space, or content

and non-content, has nothing to do with the interests implicated

and everything to do with new technologies.

This Article explores how digitization is challenging formal dis-

tinctions in Fourth Amendment doctrine that previously have

played a role in protecting the right to privacy.

The purpose, con-

sistent with the aim of the NYU Annual Survey of American Law, is to

ONFERENCE

, BDA 2015,

, 28–30 (Naveen Kumar & Vasudha Bhatnager eds.,

2015) (using YouTube metadata to identify extremists); id. at 30–32 (using Twitter

metadata to detect hate-promoting content and predict civil unrest); Carson Kai-

Sang Leung & Fan Jiang, Big Data Analytics of Social Networks for the Discovery of “Fol-

lowing” Patterns, in

ATA

NALYTICS AND

NOWLEDGE

ISCOVERY

, 17

NTERNA-

TIONAL

ONFERENCE

, D

K 2015

, at 123, 126–134 (Sanjay Madria & Takahiro

Hara eds., 2015) (using metadata to determine relationships between individuals

in social networks).

8. For further discussion of the conditions under which the e-mail could be

read for foreign intelligence purposes, see generally

ONOHUE

, F

UTURE

, supra note

9. There are other distinctions and aspects of Fourth Amendment doctrine

that this article does not consider. For instance, searches of personal devices give

rise to a range of questions about the limits of plain view doctrine and ways in

which such searches can be narrowed to avoid a descent into a general warrant.

For a thoughtful discussion of this point, see generally Orin S. Kerr, Searches and

Seizures in a Digital World, 119

ARV

. L. R

531 (2005). The argument recurs in

Orin S. Kerr, Digital Evidence and the New Criminal Procedure, 105

OLUM

. L. R

279, 300 (2005). Another distinction made in the statutory realm is between stored

communications and communications in transit, with the latter given more protec-

tions. Some commentators have argued that law enforcement has exploited this

distinction to afford the type of digital information held by ISPs (photographs, e-

mail, bank records, and medical records) a lower level of protection. See, e.g.,

James M. O’Neil, Note, The Impact of VoIP Technology on Fourth Amendment Protections

Against Electronic Surveillance, 12

NTELL

. P

ROP

. L. B

ULL

35, 42–43 (2008). I do not

address this directly in the Article as it is primarily a statutory concern.

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558 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

provide an overview of where the doctrine has been and where it is

now, with some thoughts about what direction it could go to take

account of the privacy interests implicated by the digital world.

This Article postulates that four Fourth Amendment dichoto-

mies (private vs. public space; personal vs. third party data; content

vs. non-content; and domestic vs. international) are breaking down

in light of new and emerging technologies. The distinctions are be-

coming blurred. Information previously protected is no longer

guarded. The categories themselves are failing to capture impor-

tant privacy interests, so fewer protections are being granted at the

outset. Simultaneously, the absence of use restrictions in Fourth

Amendment doctrine blinds the law to the deeper privacy interests

at stake. Legal doctrines that fail to recognize any privacy interest in

the collection of information at the outset prove inadequate to ac-

knowledge interests that later arise apparently ex nihilo,

despite

the fact that more serious inroads into privacy occur with the re-

cording of data, extended collection, and further analysis of the in-

formation. In addition, as the collection and analysis of information

requires fewer and fewer resources, constraints that previously

played a key role in protecting privacy are dropping away. The way

in which the digital era interacts with the doctrine is steadily con-

stricting the right to privacy. If no steps are taken to stem the tide,

privacy interests will continue to narrow with significant long-term

implications.

Part II of this Article begins the survey by focusing on the terri-

torial grounding of Fourth Amendment doctrine at the founding.

It describes the Court’s literal, textual reading of “houses” as mat-

ters within the home, while explaining that “papers” meant that let-

ters sent through the post received the same protections as items

10. The journal, which was founded in 1942, aims to provide a comprehen-

sive summary of developments in American law. See Mission, N.Y.U. Annual Survey

of American Law, https://annualsurveyofamericanlaw.org/aboutus/ (last visited

Nov. 2, 2016).

11. See, e.g., In re Application of the Federal Bureau of Investigation for an

Order Requiring the Production of Tangible Things from [Redacted Text], BR 13-

109, at 9 (FISA Ct. Aug. 29, 2013), https://www.aclu.org/files/assets/br13-09-pri-

mary-order.pdf (“[W]here one individual does not have a Fourth Amendment in-

terest, grouping together a large number of similarly-situated individuals cannot

result in a Fourth Amendment interest springing into existence ex nihilo.”). Some

commentators have argued for a continued adherence to this approach, despite

the privacy interests implicated by long-term surveillance. See, e.g., Orin Kerr, The

Mosaic Theory of the Fourth Amendment, 111

ICH

. L. R

311, 353–54 (2012) (re-

jecting the concerns of the shadow majority in United States v. Jones, 132 S.Ct. 945

(2012)).

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 559

inside the home.

The doctrine hewed to a three-dimensional

worldview. But with the advent of the telephone, the question of

how to protect similar interests with regard to voice communica-

tions created difficulties.

Part III begins with Katz v. United States,

which aspired to

rather more than it delivered. Even as it (ostensibly) wrenched rea-

sonableness from a territorial tie, the Court entrenched the pri-

vate/public distinction.

The persistence of the open fields

doctrine, the establishment of aerial surveillance, and the Court’s

failure to acknowledge the impact of tracking technologies on per-

sonal liberty reinforced the dichotomy. Thermal scanning under-

scored the reliance on line-drawing in three-dimensional space.

This Article focuses on location tracking to illustrate gaps in the

Court’s jurisprudence that result from new technologies.

Part IV turns to the distinction between personal information

and third party data, noting that the constellation of cases from the

1970s similarly fails to acknowledge the ever-deepening privacy in-

terests of a digital age. Increasing dependence on technology

means that the amount of private information at stake is

considerable.

Part V considers the content versus non-content dichotomy,

noting that technology is blurring the distinction. Electronic com-

munications that convey content are not currently protected, even

as areas traditionally considered to fall on the non-content side of

the line, such as data from pen register (or trap and trace devices)

or envelope information, provide insight into individuals’ private

affairs.

Part VI focuses on the domestic versus international distinc-

tion. It begins by recognizing that the Fourth Amendment did not

initially extend beyond the United States. In 1967, the Court

changed course for U.S. persons overseas, granting limited protec-

12. Besides Dow Chem. Co. v. United States, 476 U.S. 227 (1986), discussed infra,

this Article does not explore the complexity of Fourth Amendment doctrine with

regard to businesses. See, e.g., Minnesota v. Carter, 525 U.S. 83 (1998). For addi-

tional discussion, see, for example, Russell L. Weaver, The Fourth Amendment, Pri-

vacy and Advancing Technology, 80

ISS

. L. J.

1131, 1162–63, 1174–77, 1202–05

(2011).

13. 389 U.S. 347 (1967).

14. See Weaver, supra note 12, at 1222 (suggesting that the post-Katz cases

actually digressed with regard to standing doctrine, while “the Court’s post-Katz

technology decisions are a bit more of a mixed bag. However, in a number of those

cases, the Court has restrictively construed the [reasonable expectation of privacy]

test;” nevertheless, the author finds some “heartening trends for privacy in some

recent decisions.”).

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560 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

tions. In 1990, it determined that non-U.S. persons located abroad

and lacking a substantial connection to the U.S. hold no constitu-

tional rights under the Fourth Amendment. This section contrasts

the law enforcement approach with that adopted in the foreign in-

telligence realm, which similarly draws a line at the border. The

problem comes in the form of new technologies, which doggedly

refuse to recognize terrestrial boundaries. Domestic communica-

tions may now travel outside the country, simply by nature of how

the Internet works. In so doing, they lose protections that they oth-

erwise would have had, had they stayed within the country.

Part VII concludes by highlighting the importance of re-think-

ing the theoretical framing for the Fourth Amendment. While

some commentators have suggested that legislation is the most ap-

propriate vehicle to address Fourth Amendment concerns, it is to

the Courts we must look to for relief. The questions posed by the

digital age are profound. Failure to address them in a meaningful

way will lead to continually narrower constitutional protections, at

great cost to liberty in the United States.

II.

LITERAL READING OF THE TEXT

Fourth Amendment doctrine has long recognized the impor-

tance of protecting individuals within their homes from govern-

mental intrusion. Prior to the 1970s, it afforded what people did in

public, or made visible to others, considerably less protection. The

doctrine reflected a literal reading of the text. The right of the peo-

ple to be secure in their homes meant precisely that, just as the

right to be secure in one’s papers afforded special protections to

correspondence. Letters inside an envelope and sent through the

post obtained the same protections as papers held inside the home.

Once the letters were sealed and blocked from the sight of prying

eyes, the fact that they were being transmitted in the mail did not

alter the underlying privacy interests. Any effort to intercept and to

read such documents amounted to a search, making warrantless ac-

cess presumptively unreasonable.

The rationale made sense. One knew when one entered into

public space that what was said and done could be seen and heard

by others. If any citizen could witness others’ behavior, why should

government officials, who also happened to be present, not be al-

lowed to do the same? Similarly, one could hardly expect postal

employees sorting the mail, or a postman delivering a letter, to

avert their gazes from the writing on the back of a post card situ-

ated adjacent to the address. If they could see it, why shouldn’t law

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 561

enforcement? A different rule applied to correspondence hidden

from public view. Taking the step to open the letter altered the

behavior in question and the privacy rights entailed.

The concepts on which the distinction rested (the risk assumed

by individuals doing things in public, in front of other people, and

the absurdity of directing people to close their eyes, avert their

gazes, or otherwise ignore their senses) became intertwined. What

was visible in public to others did not fall within the protections of

the Fourth Amendment. In contrast, where the government wanted

to intrude on the sanctity of the home, outside of exigent circum-

stances, it was forced to approach a judge, to present evidence,

under oath, of criminal activity, and to obtain a warrant that de-

tailed precisely what was to be searched, or who or what would be

seized, from where. Similarly, if officers wanted to read a letter lo-

cated in a sealed envelope, they had to first obtain a warrant.

The line was drawn in the physical world, at the border of the

home, or the parchment that made up the envelope. What was in-

side a home or an envelope, was de facto private, while what oc-

curred outside the physical bounds of the home or the envelope

was, with some exceptions, generally public.

A. Houses

For centuries prior to the founding of the United States, En-

glish common law afforded individuals’ homes special protec-

tions.

Legal treatises detailed limits that prevented officers of the

Crown from entering domiciles absent sufficient cause and/or ap-

plication to a magistrate, demonstrating, under oath, probable

cause of criminal activity.

English jurists, lawyers, and Parliamen-

15. For discussion on the origins of the Fourth Amendment and its ties to

English legal treatises and cases, see generally Laura K. Donohue, The Original

Fourth Amendment

83 U. Chi. L. Rev. 1181 (2016) [hereinafter Donohue, Original].

Chapter Four of

AURA

K. D

ONOHUE

, T

UTURE OF

OREIGN

NTELLIGENCE

: P

RI-

VACY AND

URVEILLANCE IN A

IGITAL

(2016)

provides a broad overview of the

founding generation’s aim in enacting the Fourth Amendment, while Chapter Five

focuses on general warrants. For purposes of this Article, citations related to the

original meaning of the Fourth Amendment are to the Chicago Law Review article,

which goes into greater detail than the book. For individuals interested in a

broader overview, see generally

ONOHUE

, F

UTURE

, chs. 4, 5.

16. Id. at 1235. In 1604, Sir Edward Coke famously proclaimed in Semayne’s

Case “[t]hat the house of everyone is to him as his castle and fortress, as well for his

defence against injury and violence, as for his repose.” Semayne’s Case, (1604) 77

Eng. Rep. 194, 195 (K.B.), 5 Co. Rep. 91 a, 93 b. In 1628 Coke reiterated this view

in his Institutes of the Laws of England: “[F]or a mans [sic] house is his castle, et

domus sua cuique est tutissimum refugium [and each man’s home is his safest ref-

uge].”

DWARD

OKE

, T

HIRD

ART OF THE

NSTITUTES ON THE

AWS OF

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562 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

tarians similarly extolled the importance of protecting the home

from undue government interference.

NGLAND

: C

ONCERNING

IGH

REASON

AND

THER

LEAS OF THE

ROWN

AND

RIMINALL

ASES

162 (London, M. Flesher 1648). In 1736, Sir Matthew Hale un-

derscored the protections afforded under common law, detailing the conditions

under which justices of the peace, sheriffs, constables, or watchmen could breach

one’s walls. See 2

ATTHEW

ALE

, T

ISTORY OF THE

LEAS OF THE

ROWN

85–95

(1736); see also Donohue, Original, supra note 15, at 1235–36 (detailing the condi-

tions under which the home could be breached). William Blackstone in his Com-

mentaries on the Laws of England, expounded on Coke, tying the right to be secure in

one’s abode back to Ancient Rome:

[T]he law of England has so particular and tender a regard to the immunity

of a man’s house, that it stiles it his castle, and will never suffer it to be violated

with impunity: agreeing herein with the sentiments of ancient Rome, as ex-

pressed in the words of Tully; ‘quid enim sanctius, quid omni religione munitius,

quam domus uniuscujusque civium?’ [‘For what is more sacred, what more invio-

lable, than the house of every citizen’]

ILLIAM

LACKSTONE

, C

OMMENTARIES ON THE

AWS OF

NGLAND

(Clarendon

1769) 223 (footnote omitted). William Hawkins’ Pleas of the Crown reinforced the

point, citing to Hale’s conditions of entry to emphasize the special place accorded

to dwellings. 2

ILLIAM

AWKINS

, P

LEAS OF THE

ROWN

139 (London, Whieldon

6th ed. 1787), https://play.google.com/store/books/details?id=2qYDAAAAQAAJ

&rdid=book-2qYDAAAAQAAJ&rdot=1; see also Donohue, Original, supra note 15, at

1215–17 (discussing the writings of Hale and Hawkins).

17. In Wilkes v. Wood, an action in trespass, John Glynn argued that the case

“touched the liberty of every subject of this country, and if found to be legal, would

shake that most precious inheritance of Englishmen.” (1763) 98 Eng. Rep. 489,

490 (C.P.); see also Donohue, Original, supra note 15, at 1199–1204 (discussing

Wilkes v. Wood). Glynn protested: “In vain has our house been declared, by the law,

our asylum and defence, if it is capable of being entered, upon any frivolous or no

pretence at all, by a Secretary of State.” Wilkes, 98 Eng. Rep. at 490. Commenting

on the award of £1000 in damages, the The London Chronicle observed, “By this

important decision, every Englishman has the satisfaction of seeing that his home

is his castle.”

14 T

ONDON

HRONICLE

550

(Dec. 8, 1763). In Entick v. Car-

rington, another case brought in trespass, Charles Pratt, Chief Justice of the Com-

mon Pleas (and, from July 1765, Lord Camden), rejected the potential for a

general warrant to overcome the protections otherwise afforded to dwellings. John

Entick’s home had been “rifled; [and] his most valuable secrets [ ] taken out of his

possession,” before he had been convicted of any crime. (1765) 19 Howell’s State

Trials 1029, 1064 (C.P.). “This power so claimed by the secretary of state,” Pratt

observed, “is not supported by one single citation from any law book extant. It is

claimed by no other magistrate in this kingdom but himself.” Id.; see also Donohue,

Original, supra note 15, at 1196–99 (discussing Entick). The reason for an absence

of such authority was apparent: “The great end, for which men entered into soci-

ety, was to secure their property.” Entick, 19 Howell’s State Trials, at 1066. The

Chief Justice continued:

By the laws of England, every invasion of private property, be it ever so min-

ute, is a trespass. No man can set his foot upon my ground without my license,

but he is liable to an action, though the damage be nothing; which is proved

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 563

Upon crossing the Atlantic, the American colonists expected

the same protections that they held in England. When the Crown

failed to respect the common law limits, the seeds of revolution

were sown. In his celebrated oration in Paxton’s Case in 1761, James

Otis declared, “[O]ne of the most essential branches of English lib-

erty is the freedom of one’s house. A man’s house is his castle; and

whilst he is quiet, he is as well guarded as a prince in his castle.”

The following year, John Dickinson, author of Letters from a Farmer

in Pennsylvania, invoked the same ancient liberty. He attacked the

Townshend Acts, which allowed the Crown to enter into “any

HOUSE, warehouse, shop, cellar, or other place.”

John Adams ob-

served in 1774,

An Englishmans dwelling House is his Castle. The Law had er-

ected a Fortification round it—and as every Man is Party to the

Law, i.e., the Law is a Covenant of every Member of society with

every other Member, therefore every Member of Society has

entered into a solemn Covenant with every other that he shall

enjoy in his own dwelling House as compleat a security, safety

and Peace and Tranquility as if it was surrounded with Walls of

by every declaration in trespass, where the defendant is called upon to answer

for bruising the grass and even treading upon the soil.

Id. The sanctity of the home so permeated legal culture that the political elite

spoke of it in Westminster. William Pitt (the Elder), 1st Earl of Chatham and Lord

Privy Seal, declared:

The poorest man may, in his cottage, bid defiance to all the forces of the

Crown. It may be frail; its roof may shake; the wind may blow through it; the

storm may enter; the rain may enter; but the King of England may not enter;

all his force dares not cross the threshold of the ruined tenement.

HOMAS

M. C

OOLEY

, A T

REATISE ON THE

ONSTITUTIONAL

IMITATIONS

HICH

EST

UPON THE

EGISLATIVE

OWER OF THE

TATES OF THE

MERICAN

NION

425 n.1 (7th

ed. 1903) (quoting Chatham). See also Donohue, Original, supra note 15, at 1238

(quoting and discussing Chatham’s statement in Parliament).

18. Brief of James Otis, Paxton’s Case (Mass. Sup. Ct. 24–26 Feb. 1761). Cf.

Raleigh, Opinion, 3

ASSACHUSETTS

, Apr. 29, 1773, at 1, cols. 1–2 (discussing

the problems with royal officers seizing traders’ property without “proper cause”).

See also Donohue, Original, supra note 15, at 1251.

19. John Dickinson, Letter IX, in

MPIRE AND

ATION

: L

ETTERS FROM A

ARMER

ENNSYLVANIA

51, 54 (Forrest McDonald ed., Liberty Fund Indianapolis 2d ed.

1999), http://oll.libertyfund.org/titles/690. For Dickinson, “[T]he greatest as-

serters of the rights of Englishmen have always strenuously contended, that such a

power was dangerous to freedom, and expressly contrary to the common law, which

ever regarded a man’s house as his castle, or a place of perfect security.” Id.; see also

Donohue, Original, supra note 15, at 1261 (discussing Dickinson’s letter).

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564 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

Brass, with Ramparts and Palisadoes and defended with a Gar-

rison and Artillery.

The Fourth Amendment cemented the home as a protected sphere

into the U.S. Constitution.

It prohibited entry outside of limited

circumstances absent a warrant supported by oath or affirmation

relating to a named offense and particularly describing the place or

persons to be searched and persons or things to be seized.

The common law legacy persisted in American legal thought.

In 1833 Justice Joseph Story noted in his Commentaries on the Consti-

tution that the Fourth Amendment amounted to “little more than

the affirmance of a great constitutional doctrine of the common

law.”

Thirty-five years later Thomas Cooley wrote in his treatise:

“The maxim that ‘every man’s house is his castle,’ is made part of

our constitutional law in the clauses prohibiting unreasonable

searches and seizures, and has always been looked upon as of high

value to the citizen.”

In 1886, Justice Bradley recalled Chief Jus-

tice Pratt’s judgment in Entick: “The principles laid down in this

opinion affect the very essence of constitutional liberty and secur-

ity.”

Bradley continued:

[T]hey apply to all invasions on the part of the government

and its employees of the sanctity of a man’s home and the

privacies of life. It is not the breaking of his doors, and the

rummaging of his drawers, that constitutes the essence of the

offence; but it is the invasion of his indefeasible right of per-

sonal security, personal liberty, and private property.

20. John Adams, Adams’ Minutes of the Review, in 1

EGAL

APERS OF

OHN

D-

AMS

128

, 137 (L. Kinvin Wroth & Hiller B. Zobel eds., 1965).

21. See Donohue, Original, supra note 15, at 1188.

22. See id. at 1193.

23. It also continued to be reflected in English law and legal treatises. See, e.g.,

RANCIS

IEBER

, O

IVIL

IBERTY AND

ELF

-G

OVERNMENT

60 (Theodore D. Woolsey

ed., J.B. Lippincott & Co. 3d ed. 1883) (“[N]o man’s house can be forcibly

opened, or he or his goods be carried away after it has thus been forced, except in

cases of felony, and then the sheriff must be furnished with a warrant, and take

great care lest he commit a trespass. This principle is jealously insisted upon.”).

24.

OSEPH

TORY

, 3 C

OMMENTARIES ON THE

ONSTITUTION OF THE

NITED

TATES

§ 1895 (Boston, Hilliard, Gray & Co. 1833).

25.

OOLEY

, supra note 17, at 425–26; see also Donohue, Original, supra note

15, at 1307 (discussing Cooley’s writings on the Fourth Amendment).

26. Boyd v. United States, 116 U.S. 616, 630 (1886); see also Donohue, Origi-

nal, supra note 15, at 1308–13 (discussing the historical and legal background of

Boyd).

27. Boyd, 116 U.S. at 630; see also Bram v. United States, 168 U.S. 532, 544

(1897) (commenting in relation to Boyd, “[I]t was in that case demonstrated that

[the Fourth and Fifth Amendments] contemplated perpetuating, in their full effi-

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 565

To provide a remedy for a violation of the right, in 1914 the

Court adopted the exclusionary rule, prohibiting the government

from using evidence obtained from an unreasonable search or

seizure.

The case, Weeks v. United States, arose from the arrest of a

resident of Kansas City, Missouri.

While the suspect was being

held in custody, law enforcement went to his home, found a hidden

key, entered the house, and conducted a search.

The Court

balked at the officers’ actions, as well as those of a U.S. marshal,

who similarly searched the home.

Neither search had been sup-

ported by a warrant.

Absent a remedy, the right could not be se-

cured. The Court explained, “[T]he Fourth Amendment . . . put

the courts of the United States and Federal officials, in the exercise

of their power and authority, under limitations and restraints [and]

. . . forever secure[d] the people, their persons, houses, papers and

effects against all unreasonable searches and seizures under the

guise of law.”

Whatever position one may have on the exclusionary rule as an

effective, or even a constitutional, remedy, the fact that the Court

considered it necessary underscored the distinction between the

cacy, by means of a constitutional provision, principles of humanity and civil lib-

erty, which had been secured in the mother country only after years of struggle, so

as to implant them in our institutions in the fullness of their integrity, free from

the possibilities of future legislative change.”).

28. Weeks v. United States, 232 U.S. 383, 398 (1914).

29. Id. at 387.

30. Id. at 386.

31. Id. at 386.

32. Id.

33. Id. at 391–92. A few years after Weeks, the Court considered a parallel fact

pattern in Silverthorne Lumber Co. v. United States, 251 U.S. 385 (1920). Frederick

Silverthorne had been indicted and arrested, and, while detained, a U.S. marshal

had gone to his business and seized his books and papers. Id. at 390. Using the

material already in its possession, the government had then drafted a new warrant

to justify its actions. Id. at 391. The Court found that it was not permissible to allow

the government to benefit from the illegal act. Id. at 391–92. Justice Holmes, writ-

ing for the Court, explained that allowing such actions would “reduce[ ] the

Fourth Amendment to a form of words. The essence of a provision forbidding the

acquisition of evidence in a certain way is that not merely evidence so acquired

shall not be used before the Court but that it shall not be used at all.” Id. at 392

(citations omitted). The Supreme Court did not apply the exclusionary rule to the

states until 1961. Mapp. v. Ohio, 367 U.S. 643, 656–57 (1961). In 1995, the Court

recognized a good faith exception to the exclusionary rule. Arizona v. Evans, 514

U.S. 1, 14 (1995). This includes when police employees err in maintaining a

database. Herring v. United States, 555 U.S. 135, 137 (2009). The exclusionary rule

similarly does not apply where law enforcement relies on binding appellate prece-

dent or on statutes invalidated subsequent to the search. Davis v. United States,

564 U.S. 229, 232, 239 (2011).

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566 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

protections afforded to the private sphere, marked by the home,

and public space.

For just as the home was sacred, what happened outside the

home was rather less so.

A decade after Weeks, the Supreme Court

34. For a comprehensive article on the exclusionary rule, see generally Chris-

topher Slobogin, The Exclusionary Rule: Is It on Its Way Out? Should It Be?, 10

HIO

. J. C

RIM

. L.

341 (2013). But note that over the past century, the rule has proven

highly contentious both in its form and its implementation.

A number of scholars support the exclusionary rule. See generally, e.g., Craig M.

Bradley, Reconceiving the Fourth Amendment and the Exclusionary Rule, 73

& C

ON-

TEMP

. P

ROBS

211 (2010); Thomas K. Clancy, The Fourth Amendment’s Exclusionary

Rule as a Constitutional Right, 10

HIO

. J. C

RIM

. L.

357 (2013); Lawrence

Crocker, Can the Exclusionary Rule Be Saved?, 84

J. C

RIM

. L. & C

RIMINOLOGY

310

(1993); Arthur G. LeFrancois, On Exorcising the Exclusionary Demons: An Essay on

Rhetoric, Principle, and the Exclusionary Rule, 53

U. C

. L. R

49 (1984); Timothy

Lynch, In Defense of the Exclusionary Rule, 23

ARV

. J. L. & P

. P

’

711 (2000);

Lawrence Rosenthal, Seven Theses in Grudging Defense of the Exclusionary Rule, 10

HIO

. J. C

RIM

523 (2013); Scott E. Sundby, Everyman’s Exclusionary Rule: The

Exclusionary Rule and the Rule of Law (or Why Conservatives Should Embrace the Exclu-

sionary Rule), 10

HIO

. J. C

RIM

. L.

393 (2013); Lane V. Sunderland, The Exclu-

sionary Rule: A Requirement of Constitutional Principle, 69

J. C

RIM

. L. & C

RIMINOLOGY

141 (1978); Donald E. Wilkes, Jr., A Critique of Two Arguments Against the Exclusion-

ary Rule: The Historical Error and the Comparative Myth, 32

ASH

. & L

L. R

881

(1975).

Other scholars have been sharply critical of the exclusionary rule or the so-

called “good faith” exception to the rule. See generally, e.g., Morgan Cloud, Judicial

Review and the Exclusionary Rule, 26

EPP

. L. R

835 (1999) (criticizing the Su-

preme Court’s focus on deterring police misconduct underlying good faith excep-

tion); David Gray, A Spectacular Non Sequitur: The Supreme Court’s Contemporary Fourth

Amendment Exclusionary Rule Jurisprudence, 50

. C

RIM

L. R

1 (2013); Kit

Kinports, Culpability, Deterrence, and the Exclusionary Rule, 21

. & M

ARY

ILL

J. 821 (2013) (criticizing the Supreme Court’s focus on deterring police miscon-

duct underlying good faith exception); Wayne R. LaFave, The Smell of Herring: A

Critique of the Supreme Court’s Latest Assault on the Exclusionary Rule, 99 J.

RIM

. L. &

RIMINOLOGY

757 (2009) (criticizing a recent “good faith” decision); Eugene

Milhizer, The Exclusionary Rule Lottery, 39

U. T

. L. R

755 (2008); Eugene

Milhizer, The Exclusionary Rule Lottery Revisited, 59

ATH

. U. L. R

747 (2010);

Eugene R. Milhizer, Debunking Five Great Myths About the Fourth Amendment Exclusion-

ary Rule, 211

. L. R

211 (2012); Richard E. Myers II, Fourth Amendment Small

Claims Court, 10

HIO

. J. C

RIM

L. 571 (2013); Gregory D. Totten, Peter D. Kos-

soris, & Ebbe B. Ebbesen, The Exclusionary Rule: Fix It, but Fix It Right, 26

EPP

. L.

887 (1999); Silas Wasserstrom & William J. Mertens, The Exclusionary Rule on

the Scaffold: But Was It a Fair Trial?,

22 A

. C

RIM

. L. R

85 (1984) (criticizing the

good faith exception); Michael T. Kafka, The Exclusionary Rule: An Alternative Per-

spective, Note, 27

. M

ITCHELL

L. R

1895 (2001).

35. Orin Kerr, in his postulation of the equilibrium theory of the Fourth

Amendment, lists as his first rule of the status quo in rule zero: “[T]he police are

always free to watch suspects in public. They can walk up to suspects and monitor

them at close range and ask them questions.” Orin S. Kerr, An Equilibrium-Adjust-

ment Theory of the Fourth Amendment, 125

ARV

. L. R

476, 484 (2011) (footnote

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 567

declared in Hester v. United States that the Fourth Amendment pro-

tection of “persons, houses, papers and effects” did not extend to

“open fields.”

Citing Blackstone’s Commentaries, Justice Holmes

added, “The distinction between the latter and the house is as old

as the common law.”

While the home held a special place in the

law, what happened outside of it obtained fewer protections.

As the administrative state expanded, whenever the Court con-

fronted potential exceptions, such as those that arose with regard to

health inspections, the bench was closely divided.

It was only

when the medical concern was sufficiently acute, and the purpose

and object of the inspection sufficiently targeted, that such intru-

sions could be tolerated. A suspected infestation of rats would suf-

fice; general inspection of the home’s structure would not.

Outside of any emergency situation, the unwarranted search of a

omitted). He takes it as given that police “can walk the beat and observe whatever

they see in public.” Id. The reason that this could even be considered a given stems

from the common law protections of the home.

36. Hester v. United States, 265 U.S. 57, 59 (1924). The case evolved in the

shadow of the Eighteenth Amendment.

U.S. C

ONST

amend. XVIII, repealed by

U.S.

ONST

amend. XXI. Revenue officers, hiding outside Hester’s home, saw him give

a bottle of what appeared to be moonshine to another person. 265 U.S. at 58.

37. Hester, 265 U.S. at 59 (citing 4

ILLIAM

LACKSTONE

, C

OMMENTARIES

*223,

*225–*26).

38. See, e.g., Frank v. Maryland, 359 U.S. 360 (1959) (upholding over four

dissenters a Baltimore City health inspector’s search for the source of a rat infesta-

tion without a warrant). In Ohio ex rel. Eaton v. Price, 364 U.S. 263 (1960), the Court

split evenly, leaving in place the decision of the Ohio Supreme Court upholding a

housing inspector’s decision to enter a plumber’s residence without a warrant. The

opinion, split four to four, is without force of precedent. But in this case, the four

Justices that did not join the opinion in Ohio had already publicly expressed their

opinion that Frank controlled, id. at 264, leading the other four Justices to write an

opinion declaring Frank “the dubious pronouncement of a gravely divided Court”

and calling for reversal, id. at 269.

39. In the 1967 case Camara v. Mun. Court, the Court stated that the purpose

of the Fourth Amendment, enforceable against the states through the Fourteenth

Amendment, was to protect citizens against “unreasonable searches and seizures.”

387 U.S. 523, 528 (1967). Outside of carefully defined contours, an unconsented,

warrantless search is per se unreasonable. Id. at 528–29. In Camara, the appellant

had refused to allow housing inspectors access to his property in order to deter-

mine whether he was in violation of the occupancy permit. Id. at 525. Delivering

the opinion of the Court, Justice White distinguished the case from Frank v. Mary-

land, in which the intrusion “touch[ed] at most on the periphery” of the Fourth

Amendment given the importance of the municipal fire, health, and housing in-

spection programs designed to ensure the habitability of the structure. Id. at 530

(citing Frank, 359 U.S. at 367). In Camara, a general inspection was too attenuated

a connection to necessity to warrant overriding the protections otherwise extended

to the home. Id. at 533. White noted that warrantless powers of entry could be

used for great mischief. Quoting Johnson v. United States, 333 U.S. 10, 14 (1948)

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568 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

private home was per se unreasonable under the Fourth

Amendment.

B. Papers

At the founding, papers in the home were subject to protec-

tions similar to those afforded to other items (and activities) within

the dwelling house.

Government officials could not simply cross

the threshold at will to read or to seize them. Beyond this, consis-

tent with common law, judges did not have the authority to issue search

warrants to seize papers as evidence of criminal activity.

This point is

worth emphasizing in the contemporary environment, not least be-

cause the Director of the Federal Bureau of Investigation, in the

context of the encryption debate, has taken to repeating a false-

hood: that, with the appropriate process, the government has al-

ways had access to what people think, say, and write.

It has not.

For nearly two hundred years, the government could not obtain pri-

vate papers—even with a warrant—when they were to be used as

evidence of criminal activity.

(finding officers’ warrantless entry into a hotel room from which the odor of burn-

ing opium emanated unconstitutional), he wrote,

The right of officers to thrust themselves into a home is also a grave concern,

not only to the individual but to a society which chooses to dwell in reasonable

security and freedom from surveillance. When the right of privacy must reasonably

yield to the right of search is, as a rule, to be decided by a judicial officer, not by a

policeman or government enforcement agent. Camara, 387 U.S. at 529.

40. The history of this protection duplicates that which is detailed in Part

II(A), supra. For further discussion of the special place afforded to papers, see

generally Donohue, Original, supra note 15.

41. See Donohue, Original, supra note 15, at 1308–14 and infra for discussion

of the mere evidence rule and its roots in common law.

42. See, e.g., James B. Comey, Dir., Fed. Bureau of Investigation, Expectations

of Privacy: Balancing Liberty, Security, and Public Safety, Remarks to the Center

for the Study of American Democracy Biennial Conference at Kenyon College, at

2–3 (Apr. 6, 2016) (transcript available at https://www.fbi.gov/news/speeches/ex-

pectations-of-privacy-balancing-liberty-security-and-public-safety); James B. Comey,

Dir., Fed. Bureau of Investigation, Remarks to the Am. Bar Ass’n Annual Meeting,

Finding the Balance We Need in Law and Life, at 2 (Aug. 5, 2016) (transcript

available at https://www.fbi.gov/news/speeches/finding-the-balance-we-need-in-

law-and-life); The Encryption Tightrope: Balancing Americans’ Security and Privacy: Hear-

ing Before the H. Comm. on the Judiciary, 114th Cong. 52–53 (2016) (statement of

James B. Comey, Dir., Fed. Bureau of Investigation) (“[F]rom the founding of this

country, it was contemplated that law enforcement could go into your house with

appropriate predication and oversight. So, to me, the logic of that tells me they

wouldn’t have imagined any box or storage area or device that could never be

entered.”).

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 569

In the nineteenth century, the Court extended the protection

of documents to papers traveling through the post. In the 1878 case

Ex parte Jackson, the Court considered whether a lottery circular,

sent in a closed envelope, deserved Fourth Amendment protec-

tions.

Justice Field, writing for the Court, noted that Congress’s

authority “to establish post offices and post roads” extended beyond

merely designating the appropriate routes, to include carriage of

the mail, its safe and swift transit, and its prompt delivery.

But

while the right to carry the mail might mean that Congress could

determine what could be carried en route, it did not give Congress

the ability to open materials in transit.

To read the Constitution in

such a manner would give Congress the authority to override rights

retained by the people.

“Letters and sealed packages . . . in the mail,” Field wrote, “are

as fully guarded from examination and inspection, except as to

their outward form and weight, as if they were retained by the parties

forwarding them in their own domiciles.”

He underscored the impor-

tance of the text: “The constitutional guaranty of the right of the

people to be secure in their papers against unreasonable searches

and seizures extends to their papers, thus closed against inspection,

wherever they may be.”

Field explained,

Whilst in the mail, they can only be opened and examined

under like warrant, issued upon similar oath or affirmation,

particularly describing the thing to be seized, as is required

when papers are subjected to search in one’s own household.

No law of Congress can place in the hands of officials con-

nected with the postal service any authority to invade the se-

crecy of letters and such sealed packages in the mail; and all

regulations adopted as to mail matter of this kind must be in

subordination to the great principle embodied in the fourth

amendment of the Constitution.

Field recognized the close relationship between the interests

protected by the Fourth Amendment and those protected by the

First Amendment.

Any restrictions on the transfer of mail also vio-

lated the freedom of the press: “[l]iberty of circulating,” Field

pointed out, “is as essential to that freedom as liberty of publish-

43. Ex parte Jackson, 96 U.S. 727, 728, 733 (1877).

44. Id. at 732.

45. Id. at 733.

46. Id. (emphasis added).

47. Id.

48. Id.

49. Ex parte Jackson, 96 U.S. at 733.

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570 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

ing.”

It meant nothing to claim that the press was free if Congress

could then interfere with delivery of the newspapers, or pass laws

limiting the circulation of written material.

Even as the Court allowed for private correspondence to be

subject to the same protections as papers held within the home, a

terrestrial test applied: documents became protected as if they still

resided inside one’s domicile. Delivering the letter did not divorce it

of the protections it otherwise enjoyed. In a three-dimensional

world, where the government itself carried the letter, a clear line

could be drawn. Absent good cause, officials could neither break

into a study nor tear open an envelope en route to gain access.

Ex parte Jackson dealt with a lottery circular sent through the

post. Other efforts to flesh out the contours of protections applied

to papers followed. Just three years prior to the Court’s ruling in

Jackson, Congress had passed a statute to prevent smuggling.

The

law authorized judges to direct the production of private books, in-

voices, and papers in revenue cases.

Fourteen years later, in Boyd

v. United States, the Supreme Court declared the provision to be

unconstitutional and void.

In doing so, the Court recognized the

close relationship between the Fourth and Fifth amendments, not-

ing that:

[A] compulsory production of a man’s private papers to estab-

lish a criminal charge against him, or to forfeit his property, is

within the scope of the Fourth Amendment to the Constitution

in all cases in which a search and seizure would be, because it is

a material ingredient, and effects the sole object and purpose

of search and seizure.

The Court dismissed Congress’s effort to gain control over private

papers as being almost arrogant, noting the absence of any similar

effort in history, despite the egregious nature of measures imple-

mented by the British government. “Even the act under which the

obnoxious writs of assistance were issued,” the Court wrote, “did

not go as far as this.”

The effort to recover stolen goods, moreo-

ver, for which a warrant historically had been required, fell short of

50. Id.

51. Id. at 734.

52. Act of June 22, 1874, ch. 391, 18 Stat. 186.

53. Sec. 5, 18 Stat. at 187 (requiring surrender of books, invoices, and papers

required in civil suits under revenue laws).

54. Boyd v. United States, 116 U.S. 616, 638 (1886).

55. Id. at 622.

56. Id. at 623.

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 571

the level of intrusion now contemplated by the legislature.

The

Court explained:

The search for and seizure of stolen or forfeited goods . . . are

totally different things from a search for and seizure of a man’s

private books and papers for the purpose of obtaining informa-

tion therein contained, or of using them as evidence against

him. The two things differ toto coelo. In the one case, the gov-

ernment is entitled to the possession of the property; in the

other it is not.

Justice Bradley, writing for the Court in Boyd, cited back to

Coke and noted Otis’s oration in Paxton’s Case.

The government

could not break into an individual’s home to obtain the docu-

ments; neither could it force an individual to produce the same

information, as such an action would trigger the protection against

self-incrimination.

Boyd evolved into the “mere evidence” rule, which established

that only criminal instrumentalities and stolen goods could be re-

covered by warrants consistent with the Fourth Amendment.

1917, when Congress introduced the first law giving federal law en-

forcement the formal authority to issue search warrants, the legisla-

ture was careful to hew to the doctrinal line.

It limited warrants

for search and seizure to property “stolen or embezzled in violation

of a law of the United States,” “used as the means of committing a

felony,” or used to aid a foreign government in violating “any penal

statute[,] . . . treaty or the law of nations”.

These reflected the rule

that only the fruits or instrumentalities of crime could be obtained

via warrant.

57. Donohue, Original, supra note 15.

58. Boyd, supra note 54, at 623.

59. Id. at 625, 629 (quoting Paxton’s Case). See also supra Part II(A).

60. See Boyd, 116 U.S. at 630–35.

61. See Donohue, Original, supra note 15, at 1308–14 (discussing Boyd and the

origins of the mere evidence rule, and suggesting that instead of inventing it out of

whole cloth, the Court’s adherence to it reflected a long practice of rejecting the

use of search and seizure to obtain evidence against individuals.).

62. Act of June 15, 1917, ch. 30, tit. XI, § 2, 40 Stat. 217, 228; William T.

Rintala, The Mere Evidence Rule: Limitations on Seizure Under the Fourth Amendment, 54

. L. R

2099, 2103 (1966) (recognizing the statute as “the first general statute

authorizing the issuance of search warrants to federal officers”); see generally

Thomas H. Davis, The “Mere Evidence” Rule in Search and Seizure, 35 Mil. L. Rev. 101

(1967) (analyzing the history and legal background of the mere evidence rule).

63. § 2, 40 Stat. at 228, 230.

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In 1921, the mere evidence rule reached what one commenta-

tor has referred to as its “zenith.”

In Gouled v. United States the

Court considered whether the warrantless removal of a paper from

a defendant’s office violated the Fourth Amendment.

Justice

Clarke, on behalf of the Court, observed that making a search by

stealth did not make it more reasonable than if the same were ac-

complished “by force or illegal coercion.”

He continued,

The security and privacy of the home or office and of the pa-

pers of the owner would be as much invaded and the search

and seizure would be as much against his will in the one case as

in the other, and it must therefore be regarded as equally in

violation of his constitutional rights.

Based on Boyd, the admission of the papers as evidence violated the

Fifth Amendment.

The difficulty of differentiating the instrumentalities of crime

from mere evidence ultimately led to the demise of the mere evi-

dence rule.

But even as it fell from use, courts agonized over the

implications of giving the government access to private papers.

According to one commentator, the reasons for this appear to be

twofold.

First was the risk that the government would engage in

searches beyond what was required.

As Judge Learned Hand ex-

plained in 1926, “It is seldom that one finds a document containing

evidence of crime which was not at one time used in its commis-

sion.”

But to find such evidence often required “a thorough

64. Rintala, supra note 62, at 2105–13 (analyzing, inter alia, Marron v. United

States, 275 U.S. 192 (1927); United States v. Lefkowitz, 285 U.S. 452 (1932); Foley

v. United States, 64 F.2d 1 (5th Cir.), cert. denied, 289 U.S. 762 (1933)).

65. 255 U.S. 298, 303 (1921).

66. Id. at 305.

67. Id. at 305–06.

68. Id. at 306.

69. See Warden v. Hayden, 387 U.S. 294, 310 (1967). Warden was decided on

May 29, 1967; in October of the same year, the Court heard oral argument in Katz,

issuing its opinion that December. Katz v. United States, 389 U.S. 347 (1967). No-

tably, in Warden, the circumstances of the search under consideration, which in-

volved a fleeing felon, Warden, 387 U.S. at 297–98, overlapped with a long-standing

exception to the warrant requirement, making the question of the mere evidence

rule rather beside the point, see Donohue, Original, supra note 15, at 1228–35 (dis-

cussing the history of the fleeing felon exception).

70. See Rintala, supra note 62, at 2115.

71. Id.

72. Id.

73. United States v. Kirschenblatt, 16 F.2d 202, 204 (2d Cir. 1926); see also

Rintala, supra note 62, at 2115 (citing and discussing Kirschenblatt).

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 573

search of all that the offender has.”

Should the courts allow this,

however, they would be endorsing “exactly what [the Fourth

Amendment] was designed to prevent.”

“Therefore,” Hand con-

tinued, “we cannot agree that the power extends beyond those

which are a part of the forbidden act itself.”

Second, private papers can reveal the most intimate details of

an individual’s life. As William Rintala observed,

Private papers, be they diary or political tract, are felt to stand

on a different footing from other kinds of personal property.

This difference can be attributed at least in part to the fact that

they are products of the mind; to invade this realm is to strip

the individual of the last vestige of privacy.

C. Voice Communications

As new technologies extended interpersonal communications

beyond dwellings and channels of written correspondence, novel

questions regarding the extent of Fourth Amendment protections

emerged.

Initially, the Court came down on the side of the tradi-

tional distinction between private and public space, drawing the

line at the walls of the home.

Trespass impinged upon individual

74. Kirschenblatt, 16 F.2d at 204.

75. Id.; see also Rintala, supra note 62, at 2115.

76. Kirschenblatt, 16 F.2d at 204.

77. Rintala, supra note 62, at 2115–16 (footnote omitted).

78. For an interesting discussion of telegraphy and why it did not give rise to

similar issues, see Susan W. Brenner, The Fourth Amendment in an Era of Ubiquitous

Technology, 75

ISS

. L. J.

1, 12–16 (2005). For detail on the evolution of the tele-

phone and its place in communications, see id. at 17–21.

79. I depart here from the account offered by Professor Thomas Clancy in his

excellent treatise on the Fourth Amendment. In that work, he suggests that

“[b]eginning with Olmstead v. United States, the Court limited Fourth Amendment

rights in two important ways. First, the only things protected were tangible objects,

such as houses, papers, and physical possessions. Second, those objects were only

protected against physical invasions.”

HOMAS

K. C

LANCY

, T

OURTH

MEND-

MENT

: I

ISTORY AND

NTERPRETATION

§ 3.2.2

(2d ed. 2014) (footnote omitted)

(describing Olmstead v. United States, 277 U.S. 438 (1928)). Reflecting its com-

mon law origins, the Fourth Amendment had always been treated in this manner,

suggesting that Fourth Amendment rights were not narrowed or newly-limited, but

merely continued. Olmstead continued the traditional interpretation, until the

Court eventually moved to recognize that the same privacy interests in the tradi-

tional purview of the Fourth Amendment were implicated by voice communication

technologies. See generally Silverman v. United States, 365 U.S. 505 (1961) (finding

eavesdropping with a listening device by means of unauthorized physical penetra-

tion a violation of the Fourth Amendment). The “property-based theories of Boyd

and Olmstead,” as Clancy characterizes the concept, supra, at § 3.2.3, actually ex-

tended beyond these cases to the founding generation’s initial understanding of

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574 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

privacy. Conversely, the absence of physical entry meant that no pri-

vacy interest had been disturbed.

In Olmstead v. United States, the first case dealing with new com-

munications technology, the Supreme Court held that the wiretap-

ping of an individual’s private telephone line did not fall within

constitutional protections, as the government had not engaged in a

physical trespass.

Chief Justice Taft, delivering the opinion of the

Court, wrote, “[U]nless there has been an official search and

seizure of his person, or such a seizure of his papers or his tangible

material effects, or an actual physical invasion of his house ‘or curti-

lage’ for the purpose of making a seizure,” neither wiretapping nor

electronic eavesdropping absent a warrant violated an individual’s

Fourth Amendment rights.

A few observations about Taft’s language deserve note. First,

this is the first time that the Supreme Court used the word “curti-

lage” in relation to the validity of a search under the Fourth

Amendment.

State courts, in contrast, for more than a century

had considered the validity of search and seizure under state consti-

tutional law to turn on whether the action took place within the

curtilage.

the Fourth Amendment. See Donohue, Original, supra note 15, at 1192–93 (argu-

ing that the original meaning of the Fourth Amendment limited general searches

and seizures and required specific warrants, and emphasizing the importance of

the common law in interpreting reasonableness). Numerous secondary sources

discuss Olmstead, Goldman, and Silverman as precursors to Katz. See, e.g., Weaver,

supra note 12, at 1150.

80. Olmstead, 277 U.S. at 466.

81. Id. (emphasis added).

82. Search using Westlaw’s All Federal and All State Cases database (curtilage

OR curtelage OR curtailage) AND (seizure or warrant or warrantless) 1750 to 1921;

Search using Lexis Advance in the All Federal Cases and State Cases database with

exact phrase “curtilage” and any of these terms “search or seizure or warrant or

warrantless” 1750 to 1921; Id., using exact phrases curtilage, curtelege, and

curtailage.

83. See, e.g., Commonwealth v. Intoxicating Liquors, 110 Mass. 182, 186

(1872) (considering whether the outbuildings contained within the curtilage were

covered by a warrant); Pond v. People, 8 Mich. 150, 181 (1860) (finding in the

context of the search and seizure of a person that a fence is not necessary for a net

house to be considered within the curtilage if the space is no larger than that

which is usually occupied for the purposes of dwelling and outbuildings); Haggerty

& Nobles v. Wilber & Barnet, 16 Johns. 287, 288 (N.Y. Sup. Ct. 1819) (holding that

a sheriff has the authority to break open and seize goods, but if they are located

within the curtilage, the sheriff is precluded from entering unless the outer door is

open); Douglass v. State, 14 Tenn. 525, 529 (1834) (the validity of seizure and

arrest of rioters located in a smoke-house depends upon whether the building is

considered within the curtilage); Parrish v. Commonwealth, 81 Va. 1, 4 (1884)

(requiring a warrant for the search of corn in a tobacco house within the curti-

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 575

Second, Taft borrowed the term from criminal law, where it

derived from the common law of burglary, which increased crimi-

nal penalties for illegal activity within the curtilage.

Disagreement

marked what, precisely, counted as the curtilage.

In the early 19th

century, for instance, Jacob’s Law Dictionary defined it as “[a] court-

yard, back-side, or piece of ground lying near and belonging to a

dwelling-house.”

It incorporated buildings like out houses and

store-houses occasionally used for sleeping.

The way in which Taft

lage), overruled in part on other grounds by Fortune v. Commonwealth, 112 S.E. 861,

867 (Va. 1922); Pettus v. Commonwealth, 96 S.E. 161, 162–63 (Va. 1918) (search

of a room over a grocery store not considered within the curtilage).

84. Four years prior to Olmstead, Justice Holmes had cited back to Black-

stone’s Commentaries and the common law of burglary in support of establishing

the open fields doctrine. Hester v. United States, 265 U.S. 57, 59 (1924) (citing 4

ILLIAM

LACKSTONE

, C

OMMENTARIES

*225) (“For no distant barn, warehouse, or

the like, are under the same privileges, nor looked upon as a man’s castle of de-

fence: nor is a breaking open of houses wherein no man resides, and which there-

fore for the time being are not mansion-houses, attended with the same

circumstances of midnight terror.”). Later cases attributed Taft’s reference to cur-

tilage to stem from the common law of burglary. E.g. United States v. Dunn, 480

U.S. 294, 300 (1987).

85. State v. Langford, 12 N.C. 253, 254 (1827) (“[W]riters do not precisely

agree as to what constitutes the curtilage.”); People v. Taylor, 2 Mich. 250, 252

(1851) (“The definitions of [curtilage in] Bouviere and Chitty do not strictly agree

with [other law dictionaries].”).

86. Curtilage, 2

ACOB

’

ICTIONARY

171 (New York, Riley 1811); see also

State v. Twitty, 2 N.C. 102, 102 (1794) (defining it as “a piece of ground either

inclosed or not, that is commonly used with the dwelling house.”); State v. Shaw,

31 Me. 523, 527 (1850) (“The curtilage of a dwellinghouse is a space, necessary

and convenient and habitually used, for the family purposes, the carrying on of

domestic employments. It includes the garden, if there be one.”).

87. See, e.g., State v. Brooks, 4 Conn. 446, 448–49 (1823) (“The mansion not

only includes the dwelling-house, but also the out-houses, such as barns, stables,

cow-houses, dairy-houses and the like, if they be parcel of the messuage, though

they be not under the same roof or joining continuous to it.”) (internal quotation

marks omitted) (considering a barn to be an out-house and thus protected under

statutory provisions); People v. Parker, 4 Johns 424, 424 (N.Y. Sup. Ct. 1809) (plac-

ing store house specifically not used for sleeping, and not enclosed with the house,

outside the curtilage); State v. Wilson, 2 N.C. 242, 242 (1795) (“All out houses

standing in the same yard with the dwelling-house, and used by the owner of the

dwelling-house as appurtenant thereto, whether the yard be open or enclosed, are

in the eye of the law parts of the dwelling-house; and will satisfy that word used in

an indictment of burglary.”) (placing storehouses used occasionally for sleeping

within the curtilage); Gage v. Shelton, 3 Rich 242, 249–50 (S.C. App. L. & Eq.

1832) (noting that any out house contributory to the mansion, if placed close

enough that burning it would put the dwelling in danger, was protected against

arson); Douglass v. State, 14 Tenn. 525, 529–30 (1834) (finding a smokehouse to

be within the curtilage of the mansion house); see also Twitty, 2 N.C. at 103 (consid-

ering the out house to be within the curtilage of the home); cf. Langford, 12 N.C.

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576 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

used the term in Olmstead, though, allowed for a later reading that

considered the curtilage coterminous with the home itself. The

Court’s holding in Hester, the year before Olmstead, which distin-

guished between open fields and the home, reinforced this

reading.

Third, beyond sowing the seeds for a narrower protected

sphere, Taft gave the mistaken impression that the term carried

weight in the Court’s Fourth Amendment jurisprudence. In sup-

port of his framing, he quoted the 1921 case of Amos v. United States,

which dealt with a violation of revenue laws.

In Amos, law enforce-

ment had arrived at the defendant’s home and asked his wife for

entry.

Performing a warrantless search, they found a bottle of illic-

itly distilled whisky in a barrel of peas.

After the jury was sworn in,

but before evidence had been presented, the defendant in the

criminal case presented a sworn petition to the court, requesting

that his private property be returned to him.

According to the

Amos Court, the petition stated that the whiskey had been seized by

“officers of the Government in a search of defendant’s house and

store ‘within his curtilage,’ made unlawfully and without warrant of

any kind, in violation of his rights under the Fourth and Fifth

Amendments to the Constitution of the United States.”

The lan-

at 254 (tying the extent of the curtilage to the span of the dwelling house “and

such houses as are used as part or parcel thereof”); Commonwealth v. Sanders, 32

Va. 751, 753 (Va. Gen. Ct. 1835) (storehouse not within the curtilage of a tavern).

The term was also used in other areas of the law, further obscuring the meaning.

In cases involving land lotteries and ownership, for instance, it included yards and

other parcels of land convenient to indwellers. Southall v. M’Keand, Wythe 95,

102, 1794 WL 327, at *5 (Va. High Ch. Nov. 6, 1794). Private actions involving

matters within the curtilage of others’ homes were restricted. See, e.g., Morgan v.

Banta, 4 Ky. (1 Bibb) 579, 580 (1809); Coleman v. Moody, 14 Va. (1 Hen. & M.) 1,

2 (1809); Home v. Richards, 8 Va. (4 Call) 441, 441–42 (Va. Ct. App. 1798)

([both] cases dealing with writ of ad quod damnum in mill-dam situations). In Vir-

ginia, statutes restricted public takings of private property within the curtilage.

Commonwealth v. Beeson, 30 Va. (3 Leigh) 821, 826 (Va. Gen. Ct. 1832) (noting

that the statute imposed as a limit on the right of public takings “that in no case,

without the consent of the owner, shall the mansion house, curtilage &c. [sic] be

invaded for public purposes, whether with or without compensation.”). Liens also

turned on the concept of what fell within the curtilage. See Derrickson v. Edwards,

29 N.J.L. 468, 474 (N.J. 1861).

88. Hester, 265 U.S. at 59.

89. Olmstead, 277 U.S. at 461 (citing Amos v. United States, 255 U.S. 313, 315

(1921).).

90. Amos, 255 U.S. at 315.

91. Id. at 314–15.

92. Id. at 314.

93. Id.

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guage of the criminal defendant’s petition to the lower court was

the only reference in Amos to the curtilage of the home.

In Olmstead, Taft picked up on the language in the criminal de-

fendant’s petition, quoting it directly and then misquoting it later in

the opinion as an alternative to, or potentially a synonym for, the

home (“‘or curtilage’”).

Taft went on to rely on the absence of

any physical penetration of the curtilage as grounds to consider wire-

tapping outside the contours of the Fourth Amendment.

Justice Brandeis, joined by Justice Stone, presented a forceful

dissent that objected to the emphasis on physical penetration,

pointing to the interests at stake.

He argued that the interception

of the conversation constituted an “unjustifiable intrusion . . . upon

the privacy of the individual,” and thus violated the Fourth Amend-

ment.

Brandeis underscored what the “makers of our Constitu-

tion” had tried to accomplish: “They sought to protect Americans

in their beliefs, their thoughts, their emotions and their sensa-

tions.”

He continued, “They conferred, as against the Govern-

ment, the right to be let alone—the most comprehensive of rights

and the right most valued by civilized men.”

100

Brandeis warned

that the Court had to look not just at the current context, but also

what was coming down the pike. He cautioned,

The progress of science in furnishing the Government with

means of espionage is not likely to stop with wire-tapping. Ways

may some day be developed by which the Government, without

removing papers from secret drawers, can reproduce them in

court, and by which it will be enabled to expose to a jury the

most intimate occurrences of the home.

101

Brandeis was ahead of his time in identifying the privacy inter-

ests involved. The Court had yet to appreciate how technology had

altered the impact of the traditional distinction between private

94. See generally id. The Court ruled for the defendant, saying that Gouled, and

the mere evidence rule, controlled. Id. at 316.

95. Olmstead v. United States, 277 U.S. 438, 466 (1928).

96. Id.

97. See generally id. at 471 (Brandeis, J., dissenting); Id. at 488 (Stone, J.,

dissenting).

98. Id. at 478 (Brandeis, J., dissenting).

99. Id.

100. Id.

101. Olmstead, 277 U.S. at 474 (Brandeis, J., dissenting); see also Weems v.

United States, 217 U.S. 349, 373 (1910) (“In the application of a constitution,

therefore, our contemplation cannot be only what has been but of what may

be. . . . Rights declared in words might be lost in reality. And this has been

recognized.”).

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578 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

space and the public domain. A series of cases began hammering

on the door.

In 1942, the Court considered federal agents’ access to the of-

fice of an individual suspected of conspiring to violate criminal pro-

visions of the Bankruptcy Act.

102

Agents went into an adjoining

office, where they placed a listening device in a small aperture in

the wall.

103

When the device failed, officers used a detectaphone to

listen to conversations next door, which they recorded and tran-

scribed using a stenographer.

104

Consistent with Olmstead, the

Court found in Goldman v. United States that use of the detecta-

phone did not run afoul of the Fourth Amendment.

105

In his dissent, Justice Murphy blasted the Court for not taking

account of new technologies.

106

Referencing the acclaimed 1890

Harvard Law Review article written by Louis Brandeis and Samuel

Warren, Murphy argued for a broader reading of the Fourth

Amendment to protect individuals “against unwarranted intrusions

by others” into their private affairs.

107

Although the language of the

Fourth Amendment intimated protection against physical trespass,

Murphy averred, “[I]t has not been the rule or practice of this

Court to permit the scope and operation of broad principles or-

dained by the Constitution to be restricted, by a literal reading of its

provisions, to those evils and phenomena that were contemporary

with its framing.”

108

Of greater importance were the privacy inter-

ests that the amendment was meant to protect.

Like Brandeis in Olmstead, Murphy recognized that the “condi-

tions of modern life have greatly expanded the range and character

of those activities which require protection from intrusive action by

Government officials if men and women are to enjoy the full bene-

fit of that privacy which the Fourth Amendment was intended to

provide.”

109

It was therefore the Supreme Court’s “duty to see that

this historic provision receives a construction sufficiently liberal and

elastic to make it serve the needs and manners of each succeeding

generation.”

110

Murphy gave little countenance to whether or not a

physical entry had occurred since “science has brought forth far

102. Goldman v. United States, 316 U.S. 129, 130–31 (1942).

103. Id. at 131.

104. Id. at 131–32.

105. Id. at 135.

106. Id. at 139 (Murphy, J., dissenting).

107. Id. at 136 (Murphy, J., dissenting) (citing Louis Brandeis & Samuel War-

ren, The Right to Privacy, 4

ARV

. L. R

. 193

(1890)).

108. Goldman, 316 U.S. at 138 (Murphy, J., dissenting).

109. Id.

110. Id.

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 579

more effective devices for the invasion of a person’s privacy than

the direct and obvious methods of oppression which were detested

by our forebears and which inspired the Fourth Amendment.”

111

To the extent that electronic surveillance made it possible to do

what had hitherto been considered within the ambit of the Fourth

Amendment, so, too, ought new technologies to be considered

within the reach of the Constitution.

By the time Silverman v. United States was decided in 1961, the

intrusiveness of new technologies on interests previously guarded

by the walls of the home had become apparent.

112

The petitioner’s

brief in Silverman underscored the impact of recent advances, draw-

ing attention to parabolic microphones “which can pick up a con-

versation three hundred yards away,” experimental sound wave

technology “whereby a room is flooded with a certain type of sonic

wave . . . mak[ing] it possible to overhear everything said in a room

without ever entering it or even going near it,” and devices that

could “pick up a conversation through an open office window on

the opposite side of a busy street.”

113

But the physical characteristics

of a spike mike allowed the Court to distinguish the facts from Olm-

stead: in Silverman, since law enforcement had made physical con-

tact with a heating duct, “an unauthorized physical penetration into

the premises occupied by the petitioners” had occurred.

114

In reaching its decision, the Court recognized the extent to

which emerging technologies had proven contentious: “Eavesdrop-

ping accomplished by means of such a physical intrusion is beyond

the pale of even those decisions in which a closely divided Court

has held that eavesdropping accomplished by other electronic

means did not amount to an invasion of Fourth Amendment

rights.”

115

At the same time, the Court doubled down on the impor-

tance of the home.

116

Trespass ruled the day.

117

The importance of

111. Id. at 139.

112. See Silverman v. United States, 365 U.S. 505, 508–09 (1961) (discussing

petitioner’s description of technology enabling recording of distant

conversations).

113. Id. at 508–09 (internal quotation marks omitted); see also Weaver, supra

note 12, at 1148 (discussing Silverman).

114. Id. at 509.

115. Id. at 509–10.

116. Id. at 511 (“The Fourth Amendment, and the personal rights which it

secures, have a long history. At the very core stands the right of a man to retreat

into his own home and there be free from unreasonable governmental

intrusion.”).

117. The parallels between Silverman and United States v. Jones, 132 S. Ct. 945,

954 (2012), also decided on grounds of trespass, are of note, as Jones also signaled

a growing concern for how new technologies may affect rights otherwise protected

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580 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

drawing a distinction between the private and public realms under-

lay the Court’s approach. Behavior in the former realm was pro-

tected. But in public, individuals assumed the risk that what they

said and did would be witnessed, and potentially recalled, by others.

Silverman proved pivotal, foreshadowing the coming confronta-

tion between new technologies and the protections guaranteed in

the Fourth Amendment. While hewing to the traditional trespass

doctrine, it noted the potential for “frightening paraphernalia

which the vaunted marvels of an electronic age may visit upon

human society.”

118

In summary, the Court’s initial take when confronted by tech-

nology had been to construe the Fourth Amendment “in the light

of what was deemed an unreasonable search and seizure when it

was adopted.”

119

As Taft explained in Olmstead, “Congress may of

course protect the secrecy of telephone messages by making them,

when intercepted, inadmissible in evidence. . . . But the courts may

not adopt such a policy by attributing an enlarged and unusual

meaning to the Fourth Amendment.”

120

Where the public realm

ended and private life began, a higher standard applied. Accord-

ingly, in its June 1967 Camara v. Municipal Court decision, the Court

came out strongly on the side of drawing a border at the walls of the

home.

121

But the tension between new technologies and the ex-

isting doctrine had reached a boiling point. Just four months later,

the Court in Katz v. United States extended the protection of the

Fourth Amendment beyond physical property to include areas that

individuals considered private.

122

In doing so, the Court raised new

questions as to whether the shift to protect “people,” not “places,”

under the Fourth Amendment, but relied on traditional trespass theory for its

holding. See discussion infra Part III(D).

118. Silverman, 365 U.S. at 509; see also Alderman v. United States, 394 U.S.

165, 177–78 (1969); Berger v. New York, 388 U.S. 41, 45–47 (1967).

119. Olmstead v. United States, 277 U.S. 438, 465 (1928) (quoting Carroll v.

United States, 267 U.S. 132, 149 (1925)). In Olmstead, Chief Justice Taft wrote on

behalf of the Court, “The well known historical purpose of the Fourth Amendment

. . . was to prevent the use of governmental force to search a man’s house, his

person, his papers and his effects; and to prevent their seizure against his will.” Id.

at 463. It was the home itself that was a constitutionally protected area. “The lan-

guage of the Amendment,” Taft suggested, “can not be extended and expanded to

include telephone wires reaching to the whole world from the defendant’s house

or office. The intervening wires are not part of his house or office any more than

are the highways along which they are stretched.” Id. at 465.

120. Id. at 465–66.

121. See Camara v. Mun. Court, 387 U.S. 523, 528–29 (1967).

122. 389 U.S. 347, 351 (1967).

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created a new safeguard for activities that took place outside the

curtilage of the home.

III.

PRIVATE VERSUS PUBLIC SPACE

In 1967, the Supreme Court finally solidified around the argu-

ments articulated in the dissents in Olmstead and Goldman and in

dicta in Silverman, which recognized the impact of new technolo-

gies on privacy.

123

The Court overruled Olmstead, rejecting the idea

that the reach of the Fourth Amendment “turn[ed] upon the pres-

ence or absence of a physical intrusion into any given enclosure.”

124

More critical was whether individuals had a reasonable expectation

of privacy.

In Katz, a gambler entered a public telephone booth, closed

the door, and placed a call.

125

The privacy interests at stake could

not be ignored. Justice Stewart explained on behalf of the Court,

“The Government’s activities in electronically listening to and re-

cording the petitioner’s words violated the privacy upon which

[Katz] justifiably relied while using the telephone booth and thus

constituted a ‘search and seizure’ within the meaning of the Fourth

Amendment.”

126

The central issue was not whether physical pene-

tration of a constitutionally-protected area had occurred.

127

Stewart famously articulated, “The Fourth Amendment protects

people, not places.”

128

In his concurrence, Justice Harlan spelled out the two-part test

that would henceforward be applied. First, whether an individual,

by his or her conduct, had “exhibited an actual (subjective) expec-

tation of privacy”

129

(or, as the majority articulated, whether he had

demonstrated that “he seeks to preserve [something] as pri-

vate.”)

130

And, second, whether the subjective expectation was “one

123. Compare id., with Olmstead, 277 U.S. at 438 (Brandeis, J., dissenting), and

Goldman v. United States, 316 U.S. 129, 139 (1942) (Murphy, J., dissenting), and

Silverman v. United States, 365 U.S. 505, 508–10 (1961).

124. Katz, 389 U.S. at 353.

125. Id. at 348, 352.

126. Id. at 353.

127. Id. (“The fact that the electronic device employed to achieve that end

did not happen to penetrate the wall of the booth can have no constitutional

significance.”).

128. Id. at 351.

129. Id. at 361 (Harlan, J., concurring).

130. Katz, 389 U.S. at 351.

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582 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

that society is prepared to recognize as ‘reasonable.’”

131

The Court

would look at the circumstances to ascertain whether an individ-

ual’s expectation of privacy was justified.

132

In Katz, the Court attempted to wrench Fourth Amendment

doctrine from its tie to property rights, but it failed to deliver on its

promise. The case left open myriad questions. Over the ensuing

decade, the Court systematically worked its way through related ar-

eas, in the process modifying and carving out exceptions to the war-

rant requirement.

133

Simultaneously, the rules that evolved in the

1970s and ‘80s relied in significant measure on the physical

world.

134

It was thus not Katz’s reasonable expectation of privacy in

his communication, per se, but his reasonable expectation of privacy

when he entered the phone booth that proved central. The private/pub-

lic distinction held. Current technologies, however, blur the distinc-

tion between private space and the public domain on which the

court has relied as a way of understanding the interests at stake.

Perhaps nowhere is this more apparent than in regard to location

tracking.

A. Open Fields, Naked Eye

One of the earliest cases to reinforce the open fields doctrine

came in 1974, when the Supreme Court determined that a Colo-

rado inspector entering an individual’s yard during the daytime to

test the plumes of smoke being emitted from the homeowner’s

chimneys did not trigger Fourth Amendment protections.

135

In Air

Pollution Variance Board v. Western Alfalfa Corp., the Court went into

great detail as to what had happened, concluding that the invasion

of privacy, “if it can be said to exist, is abstract and theoretical.”

136

131. Id. at 361 (Harlan, J, concurring); see also Rakas v. Illinois, 439 U.S. 128,

143 n.12 (1978); United States v. White, 401 U.S. 745, 752 (1971) (plurality opin-

ion); Smith v. Maryland, 442 U.S. 735, 740–41 (1979).

132. Katz, 389 U.S. at 361 (Harlan, J., concurring).

133. For application of the legitimate expectation of privacy test over the dec-

ade that followed Katz, see, for example, United States v. Chadwick, 433 U.S. 1, 11

(1977); United States v. Miller, 425 U.S. 435, 442–43 (1976); Couch v. United

States, 409 U.S. 322, 335–36 (1976); United States v. Dionisio, 410 U.S. 1, 14

(1973); United States v. United States Court for E. Dist. of Mich., 407 U.S. 297, 313

(1972); White, 401 U.S. at 752; Mancusi v. DeForte, 392 U.S. 364, 368–69 (1968);

Terry v. Ohio, 392 U.S. 1, 9 (1968).

134. See discussion, infra, Part III(A).

135. 416 U.S. 861, 865 (1974).

136. Id. (“The EPA regulation for conducting an opacity test requires the in-

spector to stand at a distance equivalent to approximately two stack heights away

but not more than a quarter of a mile from the base of the stack with the sun to his

back from a vantage point perpendicular to the plume; and he must take at least

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A decade later, the Court reaffirmed its position in Oliver v.

United States.

137

Hearkening back to Hester’s (pre-Katz) reliance on

the text of the Fourth Amendment, the Court established that “ef-

fects” did not include “open fields.”

138

In Oliver, the Kentucky State

Police had received reports that a farmer was growing marijuana.

139

They searched Oliver’s property, which was surrounded by a gate

marked “No Trespassing,” without first obtaining a warrant.

140

In a

6-3 decision, Justice Powell explained that the open fields doctrine

applied.

141

Even where police officers might be engaged in a com-

mon law trespass, the act of entering a privately owned field did not

automatically trigger Fourth Amendment protections.

142

Justice

White’s concurrence noted that fields, by definition, were neither a

“house” nor an “effect.”

143

The Court recognized multiple factors for determining

whether a place should be free from government intrusion absent a

warrant.

144

It noted the importance of “the intention of the Fram-

ers of the Fourth Amendment, the uses to which the individual has

put a location, and our societal understanding that certain areas

deserve the most scrupulous protection from government inva-

sion.”

145

The factors were “equally relevant to determining whether

the government’s intrusion upon open fields without a warrant or

probable cause violates reasonable expectations of privacy.”

146

The open fields doctrine applied even when the land in ques-

tion was fenced and posted: “[A]n individual may not legitimately

demand privacy for activities conducted out of doors in fields, ex-

cept in the area immediately surrounding the home.”

147

The Court

emphasized “the overriding respect for the sanctity of the home

25 readings, recording the data at 15- to 30-second intervals. Depending upon the

layout of the plant, the inspector may operate within or without the premises but,

in either case, he is well within the ‘open fields’ exception to the Fourth Amend-

ment approved in Hester.”).

137. 466 U.S. 170 (1984).

138. Id. at 177.

139. Id. at 173.

140. Id. at 173–74.

141. Id. at 183–84.

142. Id. at 183–84.

143. Oliver, 466 U.S. at 184 (White, J., concurring).

144. Id. at 177–78.

145. Id. at 178 (citations omitted).

146. Id.

147. Id. By adopting this position, the court departed from the traditional

understanding of curtilage, as the term had been used in criminal statutes and

property disputes. See generally 1

HITTY

’

ENERAL

RACTICE

175 (London, But-

terworth 1833).

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584 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

that has been embedded in our traditions since the origins of the

Republic.”

148

Open fields, in contrast, did not provide a setting “for

those intimate activities that the Amendment is intended to shelter

from government interference or surveillance.”

149

Justice Marshall, joined by Justices Brennan and Stevens, dis-

sented.

150

Marshall could not agree “that ‘an individual may not

legitimately demand privacy for activities conducted out of doors in

fields, except in the area immediately surrounding the home.’”

151

The plain language of the amendment protected neither telephone

booths nor businesses—yet both had fallen within its contours.

152

The reason was clear: the Fourth Amendment was not designed to

specify with “precision” which activities were permissible or not, but

rather “to identify a fundamental human liberty that should be

shielded forever from government intrusion.”

153

Unlike statutes,

constitutional provisions must be understood in a way that “effectu-

ate[s] their purposes—to lend them meanings that ensure that the

liberties the Framers sought to protect are not undermined by the

changing activities of government officials.”

154

Marshall cited to

Chief Justice Marshall’s famous words in McCulloch v. Maryland,

“[W]e must never forget, that it is a constitution we are ex-

pounding.”

155

Katz had manifested this principle.

156

Marshall argued that under a Katz analysis, the Court should

look to positive law, the nature of the uses to which the space could

be put, and whether the individual claiming the privacy interest

made it clear to the public in a way that others “would understand

and respect.”

157

While privacy interests may not be coterminous

with property rights, they reflected explicit recognition of a domain

over which an individual held authority.

158

Marshall, nevertheless,

fell back upon the traditional private/public distinction: “Privately

owned woods and fields that are not exposed to public view regu-

148. Oliver, 466 U.S. at 178 (internal quotation marks omitted).

149. Id. at 179.

150. Id. at 184 (Marshall, J., dissenting).

151. Id. at 185 (Marshall, J., dissenting) (quoting id. at 178 (majority

opinion)).

152. Id. at 185–86.

153. Id. at 186.

154. Oliver, 466 U.S. at 187.

155. Id. at 187 n.4 (Marshall, J., dissenting) (quoting McCulloch v. Maryland,

17 U.S. 316, 407 (1819)).

156. Id. at 187–88.

157. Id. at 189.

158. Id. at 189–90.

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 585

larly are employed in a variety of ways that society acknowledges

deserve privacy.”

159

Oliver made it clear that Katz had not changed the basic tenets

of the open fields doctrine. For the majority, it was not that Katz did

not expand what might be included within a reasonable expecta-

tion of privacy. It simply did not incorporate open fields. For Mar-

shall, the private/public distinction similarly controlled. He merely

reached a different answer for privately owned land.

160

Questions remained about the precise limits of the curtilage.

In 1987, the Court went on to determine that the space immedi-

ately outside a barn—some half a mile from any road and only

reachable after crossing a number of fences—constituted “open

fields.”

161

In United States v. Dunn, Robert Carpenter, and his co-

defendant, Ronald Dunn, were convicted of conspiring to manufac-

ture phenylacetone and amphetamine, as well as possessing am-

phetamine with an intent to distribute it.

162

Drug Enforcement

Administration (DEA) agents discovered that Carpenter had pur-

chased significant amounts of chemicals and equipment used in the

manufacture of the controlled substances.

163

The agents obtained

warrants from a Texas state judge, allowing them to install radio

frequency-enabled transmitters in the material and equipment.

164

They tracked Carpenter’s truck until it arrived at Dunn’s ranch.

165

Aerial photographs captured images of the truck parked next to a

barn.

166

The property, some 198 acres, was encircled by a fence and

contained several interior fences, mostly constructed of posts and

barbed wire.

167

The nearest public road was a half-mile away.

168

fence surrounded the house and a nearby greenhouse, with two

barns another fifty feet away.

169

The front of one of the barns had a

wooden fence around it, along with locked, waist-high gates and

netting material stretched between the barn and the gates.

170

DEA agent and an officer from the Houston Police Department

159. Id. at 192.

160. Oliver, 466 U.S. at 192.

161. United States v. Dunn, 480 U.S. 294, 303 (1987).

162. Id. at 296.

163. Id.

164. Id.

165. Id. at 297.

166. Id.

167. Dunn, 480 U.S. at 297.

168. Id.

169. Id.

170. Id.

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586 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

crossed the outside fence and one interior fence.

171

Part way be-

tween the residence and the barns, the agent smelled phenylacetic

acid coming from the barns.

172

The officers crossed another

barbed-wire fence and a wooden fence, walked under the barn’s

overhang to the locked wooden gates, and, using a flashlight,

looked into the barn.

173

Seeing a laboratory, they did not enter the

barn, although the following day they returned twice to confirm

their initial sighting.

174

That evening, they obtained a warrant au-

thorizing them to search the ranch.

175

Two days later, they exe-

cuted the warrant, seizing chemicals, laboratory equipment, and

amphetamines.

176

The Supreme Court reiterated the special place of the home in

Fourth Amendment jurisprudence. “The curtilage concept,” the

Court wrote, “originated at common law to extend to the area im-

mediately surrounding a dwelling house the same protection under

the law of burglary as was afforded the house itself.”

177

The Court was right insofar as the curtilage had historically

been considered relevant to the penalties associated with criminal

activity. But it was not until 1928, with Taft’s decision in Olmstead,

that the term became drawn into the Supreme Court’s Fourth

Amendment jurisprudence. And prior to that time, curtilage had a

much broader meaning.

According to Cunningham’s law dictionary from 1764, for in-

stance, curtilage meant precisely what the Court rejected in Oliver:

171. Id.

172. Id.

173. Dunn, 480 U.S. at 297–98.

174. Id. at 298.

175. Id.

176. Id. at 298–99. The District Court denied the defendants’ motion to sup-

press evidence seized pursuant to the warrant—a decision later reversed by the

Fifth Circuit in United States v. Dunn, 674 F.2d 1093 (5th Cir. 1982). The Supreme

Court vacated the Fifth Circuit’s judgment and remanded it for further considera-

tion in light of Oliver v. United States, 466 U.S. 170 (1984). Dunn, 480 U.S. at 299.

The Fifth Circuit again suppressed the evidence found in the course of the agents’

first entry onto the premises—this time, not on the grounds that the barn was

within the curtilage of the house but, rather, that by peering into the structure, the

officers had violated Dunn’s “reasonable expectation of privacy in his barn and its

contents.” Id. (internal quotation marks omitted). Before the Supreme Court en-

tertained the petition for certiorari, the Fifth Circuit recalled and vacated its judg-

ment and reinstated its original opinion, stating, “[u]pon studied reflection, we

now conclude and hold that the barn was inside the protected curtilage.” Id. (in-

ternal quotation marks omitted). The Supreme Court granted certiorari, and re-

versed the Fifth Circuit. Id. at 300.

177. Dunn, 480 U.S. at 300.

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 587

“a yard, backside, or piece of ground lying near a dwelling house,

where they sow hemp, beans, and such like.”

178

In 1820, Sheppard’s

Touchstone of Common Assurances described it as “a little garden, yard,

field, or piece of void ground, lying near and belonging to the mes-

suage, and houses adjoining the dwelling house, and the close

upon which the dwelling-house is built.”

179

In 1828, Johnson &

Walker simply defined it as “a garden, yard, or field lying near to a

messuage.”

180

Oliver narrowed the meaning of the term, and the Court in

Dunn highlighted four factors to be taken into account:

[T]he proximity of the area claimed to be curtilage to the

home, whether the area is included within an enclosure sur-

rounding the home, the nature of the uses to which the area is

put, and the steps taken by the resident to protect the area

from observation by people passing by.

181

It eschewed a rigid adherence to the categories, arguing that

they were “useful analytical tools only to the degree that, in any

given case, they bear upon the centrally relevant consideration—

whether the area in question is so intimately tied to the home itself

that it should be placed under the home’s ‘umbrella’ of Fourth

Amendment protection.”

182

Applied to the barn, the Court con-

cluded that it did not.

Curtilage considerations thus dismissed, naked eye doctrine

prevailed. “Under Oliver and Hester,” the Court wrote, “there is no

constitutional difference between police observations conducted

while in a public place and while standing in the open fields.”

183

178. Curtilage

, 1 T

IMOTHY

UNNINGHAM

, A N

EW AND

OMPLETE

ICTION-

ARY

(London, Law-Printers to the King’s Most Excellent Majesty 1764), https://

archive.org/stream/newcompletelawdi01cunn#page/n613/mode/2up; see also

Curtilage, 2

ILES

ACOB

& T.E. T

OMLINS

, T

-D

ICTIONARY

: E

XPLAINING THE

ISE

, P

ROFESS

AND

RESENT

TATE

OF THE

NGLISH

171

(New York, I. Riley

1811) (“CURTILAGE, curtilagrium, from the Fr. cour, court and Sax. leagh, locus.] A

court-yard, back-side, or piece of ground lying near and belonging to a dwelling

house. And though it is said to be a yard or garden, belonging to a house, it seems

to differ from a garden, for we find cum quodam gardino et curtilagio.”) (citations

omitted).

179.

ILLIAM

HEPPARD

& E

DWARD

ILLIARD

, S

HEPPARD

’

OUCHSTONE OF

OMMON

SSURANCES

(London, 7th ed. 1820).

180. Curtilage

1 Samuel Johnson & John Walker, A Dictionary of the English

Language 176 (London, William Pickering 1827), https://books.google.com/

books/about/A_Dictionary_of_the_English_Language.html?id=WBYwAAAAYAAJ.

181. See Dunn, 480 U.S. at 301 (discussing Oliver and deriving factors from

lower courts).

182. Id.

183. Id. at 304.

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588 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

Just as the observation from a plane in California v. Ciraolo (dis-

cussed infra in Section IIIB) did not violate the Fourth Amend-

ment, neither did peering into the barn.

184

Despite Katz’s move to a

reasonable expectation of privacy as centered on persons, and not

property, the curtilage of the home continued to serve as a proxy.

In Dunn, Justice Brennan, joined by Justice Marshall, dis-

sented.

185

The reasoning paralleled their position in Oliver: the in-

trusion violated the Fourth Amendment because the barnyard “lay

within the protected curtilage of Dunn’s farmhouse,” and the

agents’ inspection violated Dunn’s reasonable expectation of pri-

vacy. Like the majority, the dissent’s logic reflected the private-

space/public domain distinction that had long marked Fourth

Amendment doctrine. Brennan did note, though, the underlying

purpose of the constitutional text: prohibiting “police activity which,

if left unrestricted, would jeopardize individuals’ sense of security

or would too heavily burden those who wished to guard their pri-

vacy.”

186

DEA agents had gone “one-half mile off a public road over

respondent’s fenced-in property, crossed over three additional

wooden and barbed wire fences, stepped under the eaves of the

barn, and then used a flashlight to peer through otherwise opaque

fishnetting.”

187

He concluded, “For the police habitually to engage

in such surveillance—without a warrant—is constitutionally

intolerable.”

188

Just a few months after Dunn, the Court beat the proverbial

horse. In California v. Greenwood,

189

local police suspected Billy

Greenwood of dealing drugs out of his home. Lacking sufficient

evidence for a warrant, they searched his garbage and found incul-

pating material. In a 6-2 vote, the Court held that the garbage left

out on the curb, “readily accessible to animals, children, scavengers,

184. In Ciraolo, the Court had observed that the Fourth Amendment “has

never been extended to require law enforcement officers to shield their eyes when

passing by a home on public thoroughfares.” California v. Ciraolo, 476 U.S. 207,

213 (1986). Also note that in 1983 the court settled that simply using a flashlight to

illuminate the interior of a car, without probable cause to search the automobile,

did not transgress any rights secured by the Fourth Amendment. Texas v. Brown,

460 U.S. 730, 739–40 (1983); see also United States v. Lee, 274 U.S. 559, 563 (1927)

(use of searchlight by Coast Guard on high seas is not a search).

185. Dunn, 480 U.S. at 305 (Brennan, J., dissenting).

186. Id. at 306.

187. Id. at 319.

188. Id.

189. California v. Greenwood, 486 U.S. 35 (1988).

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snoops, and other members of the public,” lay outside the protec-

tions of the Fourth Amendment.

190

In his dissent, Justice Brennan, joined by Justice Marshall, em-

phasized that Greenwood had placed the garbage in opaque bags,

blocking their view from casual passers-by.

191

Garbage could reveal

a considerable amount about Greenwood’s private life: “A single

bag of trash testifies eloquently to the eating, reading, and recrea-

tional habits of the person who produced it,” he wrote.

192

Search of

the material could reveal “intimate details about sexual practices,

health, and personal hygiene. Like rifling through desk drawers or

intercepting phone calls, rummaging through trash can divulge the

target’s financial and professional status, political affiliations and

inclinations, private thoughts, personal relationships, and romantic

interests.”

193

It reflected the type of “intimate knowledge associated

with the ‘sanctity of a man’s home and the privacies of life’” that

the Fourth Amendment was designed to protect.

194

The majority’s

private space/public domain distinction, premised on lesser expec-

tations outside the physical borders of the home, had failed to cap-

ture the privacy interests at stake.

B. Aerial Surveillance

With the line still drawn post-Katz at the curtilage of the home,

to the extent that new means of aerial surveillance raised privacy

concerns, the Court dismissed them under the private/public dis-

tinction. The underlying rationale, that government officials should

not be prevented from accessing what any citizen could see or hear,

persisted.

In California v. Ciraolo, the police received an anonymous tele-

phone tip that a resident of Santa Clara, California, was growing

marijuana in his backyard.

195

A six-foot outer fence and a ten-foot

inner fence blocked the view from the street, so the police hired a

private plane to fly overhead.

196

They spotted marijuana plants,

eight to ten feet tall, growing in a fifteen by twenty-five foot plot in

the back yard.

197

190. Id.

191. See, e.g., id. at 45 (Brennan, J., dissenting).

192. Id. at 50.

193. Id.

194. 486 U.S. 50–51 (Brennan, J., dissenting).

195. California v. Ciraolo, 476 U.S. 207, 209 (1986).

196. Id.

197. Id.

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Chief Justice Burger, delivering the opinion of the Court,

quickly dismissed the importance of the fence, noting that even the

ten-foot-high structure “might not shield these plants from the eyes

of a citizen or a policeman perched on the top of a truck or a two-

level bus.”

198

Burger’s statement was extraordinary, not least because it was

illegal under California law for citizens to sit atop vehicles.

199

Nor

were there, in 1982, any double-decker buses to be found in the

largely rural and residential community.

200

Nevertheless, Burger

suggested that any citizen could look over the fence from the top of

a moving vehicle. It was therefore unclear whether the respondent

had a subjective expectation of privacy or “merely a hope that no

one would observe [the respondent’s] unlawful gardening

pursuits.”

201

Turning his attention to the curtilage, the Chief Justice noted

that the common-law understanding was the area within which ac-

tivities associated with the “sanctity of a man’s home and the priva-

cies of life” occurred.

202

“The protection afforded the curtilage,” he

wrote, “is essentially a protection of families and personal privacy in

an area intimately linked to the home, both physically and psycho-

logically, where privacy expectations are most heightened.”

203

The

yard, and its crops, could be understood as inside the curtilage.

204

But the burden was on the homeowner to ensure that the view was

blocked.

205

The “naked-eye observation of the curtilage by police

from an aircraft lawfully operating at an altitude of 1,000 feet”

meant that the owner had not taken the requisite steps.

206

Any citi-

zen, flying over the home within navigable airspace, could have

seen the same thing.

207

The Fourth Amendment does not “require

law enforcement officers to shield their eyes when passing by a

198. Id. at 211.

199. See, e.g., 1981 Cal. Stat. 3, 155 (adding Subsection (b), stating that “No

person shall ride on any vehicle or upon any portion thereof not designed or in-

tended for the use of passengers,” to Cal. Veh. Code §21712); 1982 Cal. Stat. 4, 709

(passed Sept. 22, 1982 making it illegal for a minor to be in the back of a flatbed

truck, codified at Cal. Veh. Code §23116).

200. Author Note, having grown up in Santa Clara, California in the 1980s.

201. Ciraolo, 476 U.S. at 212.

202. Id. (quoting Oliver v. United States, 466 U.S. 170, 180 (1984)).

203. Id. at 212–13.

204. Id. at 213.

205. See id.

206. Id.

207. Ciraolo, 476 U.S. at 213–14.

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home on public thoroughfares.”

208

What was accessible to any per-

son, had to be accessible to law enforcement.

209

The decision was a 5-4 vote, with Justice Powell, joined by Jus-

tices Brennan, Marshall, and Blackmun, dissenting. Powell cited to

Justice Harlan’s warning in Katz, that tying the Fourth Amendment

only to physical intrusion “is, in the present day, bad physics as well

as bad law, for reasonable expectations of privacy may be defeated

by electronic as well as physical invasion.”

210

For the dissent, the

airplane was “a product of modern technology” visually intruding

into the respondent’s yard.

211

While “[c]omings and goings on

public streets are public matters,” flying a plane over a home to

conduct surveillance intrudes upon a reasonable expectation of

privacy.

212

Powell underscored the importance of the Fourth Amendment

adapting to new and emerging technologies. “Rapidly advancing

technology now permits police to conduct surveillance in the home

itself,” he explained, “an area where privacy interests are most cher-

ished in our society, without any physical trespass.”

213

Flexibility

mattered. The Court had “repeatedly refused to freeze ‘into consti-

tutional law those enforcement practices that existed at the time of

the Fourth Amendment’s passage.’”

214

Instead, it had “construed

the Amendment ‘in light of contemporary norms and conditions,’

. . . in order to prevent ‘any stealthy encroachments’ on our citi-

zens’ right to be free of arbitrary official intrusion.”

215

By the time

of Ciraolo, Powell noted, technological advances had “enabled po-

lice to see people’s activities and associations, and to hear their con-

versations, without being in physical proximity.”

216

The doctrine

had to evolve to protect the privacy interests at stake.

The same day that the Court handed down Ciraolo, it issued an

opinion in Dow Chemical v. United States, reinforcing the idea that

what was visible in public was fair game.

217

Dow Chemical denied a

208. Id. at 213.

209. Id. at 213–14.

210. Id. at 215–16 (Powell, J., dissenting) (quoting Katz v. United States, 389

U.S. 347, 362 (1967) (Harlan, J., concurring)).

211. Id. at 222.

212. Id. at 224–25.

213. Ciraolo, 476 U.S. at 226 (Powell, J., dissenting).

214. Id. at 217 (Powell, J., dissenting) (quoting Steagald v. United States, 451

U.S. 204, 217 n.10 (1981)).

215. Id. (quoting Steagald, 451 U.S. at 217; Boyd v. United States, 116 U.S.

616, 635 (1886)).

216. Id. at 218.

217. Dow Chem. Co. v. United States, 476 U.S. 227 (1986).

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request by the Environmental Protection Agency (EPA) to conduct

an on-site inspection of a 2000-acre facility.

218

The EPA responded

by hiring a commercial aerial photographer to take pictures of the

facility from the air.

219

Chief Justice Burger again wrote for the Court. He began the

Fourth Amendment analysis by drawing a line between private and

public space.

220

Activities undertaken potentially in the view of

others did not deserve the same protections as those that transpired

within the home.

221

While Dow Chemical held a “reasonable, legiti-

mate, and objective expectation of privacy within the interior of its

covered buildings” (one that society was prepared to recognize), it

did not have an equally high expectation for areas exposed to aerial

view.

222

The Court emphasized the importance of not unduly hamper-

ing law enforcement. The photographs were “essentially like those

commonly used in mapmaking. Any person with an airplane and an

aerial camera could readily duplicate them.”

223

It made no sense to

force the government agency to close its eyes, to prevent it from

seeing what anyone else could see and from memorializing the im-

age with a photograph—as any citizen could do.

224

In 1989, the Court went on to consider whether aerial surveil-

lance from a helicopter just 400 feet above the ground similarly was

exempt from Fourth Amendment protections.

225

The concept of

the naked eye—and what other citizens would be able to do in the

public realm—again figured largely in the decision.

Like the Santa Clara police in Ciraolo, a Florida county sheriff’s

office received an anonymous tip that Riley was growing marijuana

in a greenhouse behind his home.

226

Located on five acres of prop-

erty, his mobile home was surrounded by a fence, on which a sign

218. Id. at 229.

219. Id.

220. Id. at 235 (“The curtilage area immediately surrounding a private house

has long been given protection as a place where the occupants have a reasonable

and legitimate expectation of privacy that society is prepared to accept.”) (citing

Ciraolo, 476 U.S. at 207). Open fields, in contrast, “do not provide the setting for

those intimate activities that the [Fourth] Amendment is intended to shelter from

governmental interference or surveillance.” Id. (alteration in original) (quoting

Oliver v. United States, 466 U.S. 170, 179 (1984)).

221. Id. at 239.

222. Id. at 236, 239.

223. Dow Chem. Co., 476 U.S. at 231.

224. See id.

225. Florida v. Riley, 488 U.S. 445, 447–48 (1989).

226. Id. at 448.

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was posted saying, “DO NOT ENTER.”

227

Unable to see behind the

house from the street, an officer flew over the property in a helicop-

ter.

228

The greenhouse had two sides enclosed and was covered

with corrugated panels, some translucent and some opaque.

229

Two

of the panels were missing.

230

The officer looked through the open-

ings in the roof and the open sides of the greenhouse and saw the

plants growing.

231

He used this information to obtain a search war-

rant, which yielded the plants.

232

Justice White announced the judgment and wrote an opinion

in which only three other justices joined.

233

Because Riley had left

two sides of the greenhouse open, and had failed to cover the

greenhouse entirely, he “could not reasonably have expected the

contents of his greenhouse to be immune from examination by an

officer seated in a fixed-wing aircraft flying in navigable airspace at

an altitude of 1000 feet or . . . at an altitude of 500 feet, the lower

limit of the navigable airspace for such aircraft.”

234

It made no dif-

ference that the helicopter was at a height of 400 feet, as helicop-

ters were not bound by the lower limits of navigable airspace as

required for other aircraft. “Any member of the public could legally

have been flying over Riley’s property in a helicopter at the altitude

of 400 feet.”

235

Why force law enforcement to undertake a form of

willful blindness?

Justice Brennan, joined by Justices Marshall and Stevens, dis-

sented. Brennan disputed the plurality’s focus on whether any

member of the public could have conducted the activity under-

taken by law enforcement, without also considering the difficulty of

such activity and the frequency with which it was done by members

of the public. “Is the theoretical possibility that any member of the

public (with sufficient means) could also have hired a helicopter

and looked over Riley’s fence of any relevance at all in determining

whether Riley suffered a serious loss of privacy . . . ?”

236

Law en-

forcement had not been standing on a public road.

237

“The vantage

227. Id.

228. Id.

229. Id.

230. Id.

231. Riley, 488 U.S. at 448.

232. Id. at 448–49.

233. Id. at 447 (joined by Chief Justice Rehnquist, Justice Scalia, and Justice

Kennedy).

234. Id. at 450.

235. Id. at 451.

236. Id. at 457–58 (Brennan, J., dissenting).

237. Riley, 488 U.S. at 460 (Brennan, J., dissenting).

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point he enjoyed,” Brennan pointed out, “was not one any citizen

could readily share.”

238

To see over the fence, the officer had to use

“a very expensive and sophisticated piece of machinery to which few

ordinary citizens have access.”

239

It made as much sense to rely on

whether the officer was legally in the air, as it would have been to

ascertain whether the police officers in Katz were legally standing

outside the telephone booth.

240

“The question before us,” Brennan

explained, “must be not whether the police were where they had a

right to be, but whether public observation of Riley’s curtilage was

so commonplace that Riley’s expectation of privacy in his backyard

could not be considered reasonable.”

241

Brennan’s argument underscored the importance of focusing

on the privacy interests implicated by new technologies. Yet largely

because of the persistence of the private/public distinction, his ar-

guments did not win the day. Warrantless searches and seizures in-

side a home may be presumptively unreasonable absent exigent

circumstances.

242

But visual examination, even of areas inside the

curtilage of the home, when conducted from a public sphere, lies

outside the protections of the Fourth Amendment.

243

C. Radio-frequency Enabled Transmitters

As technology progressed and questions relating to the reason-

able expectation of privacy standard adopted in Katz arose, the Su-

preme Court held fast to its private/public distinction. Just as

people had a lesser expectation of privacy in garbage placed curb-

side—indeed, no expectation whatsoever—so, too, did they outside

of automobiles, as well as in their movements along public

thoroughfares.

244

238. Id.

239. Id.

240. Id.

241. Id.

242. See Welsh v. Wisconsin, 466 U.S. 740, 748–49 (1984); Steagald v. United

States, 451 U.S. 204, 211–13 (1981); Payton v. New York, 445 U.S. 573, 586 (1980).

243. Precisely what constitutes the curtilage of the home continues to be a

contentious issue in Fourth Amendment jurisprudence. See

LANCY

, supra note 79,

at § 4.4.1.1; 1

AYNE

R. L

AVE

, S

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EIZURE

: A T

REATISE ON THE

OURTH

MENDMENT

§2.3 (5th ed. 2016).

244. The seizure of a car travelling on a public highway, absent either proba-

ble cause or reasonable suspicion, did violate the Fourth Amendment. Delaware v.

Prouse, 440 U.S. 648 (1979). In Prouse, a patrol officer stopped a car and smelled

marijuana. Id. at 650. When the officer looked into the car, he saw the marijuana

inside the vehicle. Id. Justice White, writing for the Court, stated, “An individual

operating or traveling in an automobile does not lose all reasonable expectation of

privacy simply because the automobile and its use are subject to government regu-

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Thus it was in 1983, in United States v. Knotts, the Court con-

fronted a case where Minnesota law-enforcement officers suspected

Tristan Armstrong of stealing chemicals that could be used in man-

ufacturing illicit drugs.

245

Visual surveillance revealed that he pur-

chased chemicals from Hawkins Chemical Co. in Minnesota.

246

With the consent of company officials, when Armstrong next

bought a container of chloroform (one of the precursor chemicals

used to make drugs), the police placed a radio-frequency-enabled

transmitter on the container.

247

The police followed the container,

using the tracking device and visual surveillance, to a cabin in Wis-

consin.

248

They obtained a search warrant and found a fully opera-

ble drug laboratory inside the cabin, replete with formulas for

amphetamine and methamphetamine, $10,000 worth of equip-

lation.” Id. at 662. He reasoned, “Automobile travel is a basic, pervasive, and often

necessary mode of transportation to and from one’s home, workplace, and leisure

activities.” Id. Since many people spent more time driving than walking, a higher

degree of security might be felt in the car. Id. White continued, “Were the individ-

ual subject to unfettered governmental intrusion every time he entered an auto-

mobile, the security guaranteed by the Fourth Amendment would be seriously

circumscribed.” 440 U.S. 662–63.

Professor Clancy points to this case to suggest that the case served as an early

indication that, following Katz, “privacy might be a vital source of protection of

individual interests.”

LANCY

, supra note 79, at § 3.3.3. He argues, “as the composi-

tion of the Court changed,” however, “those early indications gave way to a view

that used privacy analysis not to expand protected individual interests but to limit

the scope of the Amendment’s protections.” Id. What emerged was a “hierarchy of

privacy interests.” Id. Amongst the lowest level of protection is an individual’s

voice, face, or handwriting, as well as travel and open fields. Id.

The hierarchy that Clancy identifies, though, relies on the private/public dis-

tinction as the defining feature. Lowered protections accompanied what could be

seen and observed by others in public space. Clancy treats whether something is

observable as only one of several potential methods adopted by the Court to distin-

guish between privacy interests, noting also the degree to which technological ad-

vances, empirical evidence of a subjective expectation of privacy, and degree of

government regulation. Id. at § 3.3.4. This Article takes the stronger position,

which is that the private/public distinction is a central feature of the doctrine,

which remains rooted in a terrestrial understanding of a three-dimensional world,

making it ill-suited to confront the challenges of a digital age.

245. United States v. Knotts, 460 U.S. 276, 278 (1983); cf. United States v.

Michael, 622 F.2d 744 (5th Cir. 1980) (holding that installation of a beeper, absent

probable cause and exigent circumstances, required prior judicial authorization),

reh’g granted, 628 F.2d 931 (5th Cir. 1980), rev’d, 645 F.2d 252 (5th Cir. 1981) (find-

ing the installation of the beeper permissible under the Fourth Amendment using

a reasonable suspicion standard).

246. Knotts, 460 U.S. at 278.

247. Id.

248. Id.

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ment, and enough chemicals to produce 14 pounds of pure

amphetamine.

249

The Eighth Circuit reversed the conviction on the grounds

that monitoring the radio-frequency-enabled transmitter violated

the cabin owner’s reasonable expectation of privacy.

250

The Su-

preme Court disagreed and reversed.

251

In an opinion written by

Chief Justice Rehnquist, the Court analyzed the question in terms

of the open fields/naked eye doctrine. The transmitter was merely

a battery-operated device, emitting periodic signals that could be

picked up by a receiver. It allowed law enforcement to do electroni-

cally what it could do in person “on public streets and highways.”

252

Rehnquist picked up on the 1974 language in Cardwell v. Lewis,

which stated: “A car has little capacity for escaping public scrutiny.

It travels public thoroughfares where both its occupants and its con-

tents are in plain view.”

253

In Knotts, Rehnquist argued, “A person

traveling in an automobile on public thoroughfares has no reasona-

ble expectation of privacy in his movements from one place to an-

other.”

254

The direction they took, stops they made, and their final

destination could be observed.

255

Just because the police relied on

a radio-frequency-enabled transmitter, and not their own eyes, did

not alter the situation. Rehnquist explained, “Nothing in the

Fourth Amendment prohibited the police from augmenting the

sensory faculties bestowed upon them at birth with such enhance-

ment as science and technology afforded them in this case.”

256

The respondent argued that if the Court were to adopt this

rule, then there would be no limiting condition on the eventual use

of 24-hour surveillance.

257

The Court disagreed, suggesting that

technology, in reality, was nowhere near that point. “[I]f such drag-

249. Id. at 279.

250. Id. (discussing the case below, United States v. Knotts, 662 F.2d 515 (8th

Cir. 1983)).

251. Id. at 279–80.

252. Knotts, 460 U.S. at 281.

253. Id. at 281 (quoting Cardwell v. Lewis, 417 U.S. 583, 590 (1974) (plurality

opinion) (holding the warrantless search of the outside of a car to be outside the

contours of the Fourth Amendment)) (also citing Rakas v. Illinois, 439 U.S. 128,

153–54 (1978) (Powell, J., concurring); South Dakota v. Opperman, 428 U.S. 364,

368 (1976)).

254. Knotts, 460 U.S. at 281.

255. Id. at 281–82.

256. Id. at 282; see also id. at 282–83 (discussing United States v. Lee, 274 U.S.

559, 563 (1927) (finding that the use of a searchlight is comparable to the use of a

marine glass or field glass and thus does not change the analysis of the reasonable-

ness of a search on the high seas)).

257. Id. at 283.

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net-type law enforcement practices as respondent envisions should

eventually occur, there will be time enough then to determine

whether different constitutional principles may be applicable.”

258

Radio-frequency-enabled transmitters, also known as “beepers,”

were merely “a more effective means of observing what is already

public.”

259

The following year the Court confronted a similar fact pattern

in United States v. Karo.

260

The DEA had learned that James Karo

and two others had ordered 50 gallons of ether to be used to ex-

tract cocaine from clothing that had been imported to the United

States.

261

Agents traced the container inside a number of homes,

before tracking it to a commercial storage facility.

262

Unlike Knotts, where the transmitter conveyed the location of a

car on public roads, in Karo the beeper informed the agent where a

container was located, at a particular time and, consequently, in

whose possession it was held: i.e., the person(s) whose residence

was under surveillance. “Even if visual surveillance has revealed that

the article to which the beeper is attached has entered the house,

the later monitoring not only verifies the officers’ observations but

also establishes that the article remains on the premises.”

263

The

search was less intrusive than a full-scale search, but it was still a

search of the interior of the home. It therefore fell within the pro-

tections of the Fourth Amendment.

264

The private/public distinc-

tion, and the importance of maintaining access for acquiring visual

information, held. Where law-enforcement collection techniques

crossed the curtilage, constitutional protections arose.

The ordinary operation of the senses continued to loom large

in the Court’s jurisprudence.

265

What individuals could observe in

258. Knotts, 460 U.S. at 284.

259. Id. (quoting United States v. Knotts, 662 F.2d 515, 518 (8th Cir. 1983));

see also id. at 285.

260. 468 U.S. 705, 707–10 (1984).

261. Id. at 708.

262. Id.

263. Id. at 715.

264. Id. at 716.

265. The importance of the naked eye, for instance, extends to the plain view

doctrine. In Coolidge v. New Hampshire, the Supreme Court explained that under

certain circumstances seizure of an item in plain view during a lawful search may

be reasonable under the Fourth Amendment. 403 U.S. 443, 465 (1971). Three

elements must be met: (1) the officer must be lawfully in the Fourth Amendment-

protected area; (2) the item observed must be in plain view; and (3) the officer

must immediately recognize the item as illegal materials, evidence, or contraband

without otherwise interfering with the item. Horton v. California, 496 U.S. 128,

136–37 (1990). In Arizona v. Hicks, the Court further elaborated on what consti-

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public fell outside the protections of the Fourth Amendment. Law

enforcement officers should not be forced to avert their gaze to

block out what the rest of the world could see.

The functional-senses test included not just what individuals

could see but also what they could hear without technological assis-

tance. A 1984 case from the Second Circuit, United States v.

Mankani, reflected this approach.

266

Canadian law enforcement un-

covered a drug-running operation that yielded nearly two tons of

hashish in a barn in a rural area of Vermont.

267

Having been tipped

off by Canadian authorities that two of the men involved in the

shipment were in a hotel room in Burlington, a DEA agent booked

the adjoining room and listened through a hole in the wall to the

conversation next door.

268

The Court concluded that eavesdrop-

ping did not violate the Fourth Amendment: “[D]efendants’ con-

versations were overheard by the naked human ear, unaided by any

. . . sensory enhancing devices. This distinction is significant be-

cause the Fourth Amendment protects conversations that cannot

be heard except by means of artificial enhancement.”

269

Every time

individuals spoke, they assumed the risk that someone might be

privy to what they say.

270

On the other hand, once technology en-

hanced the senses, then the risk altered. As Justice Brennan had

expressed in his dissent in Lopez v. United States, “There is no secur-

ity from that kind of eavesdropping, no way of mitigating the risk,

and so not even a residuum of true privacy.”

271

Passive observation proved central to the functional senses ap-

proach. What one could see or hear, just standing there, was not

tuted an interference under condition (c). In that case, moving and then record-

ing the serial numbers on the bottom of a stolen stereo did not amount to a

seizure, but it was a search under the Fourth Amendment. Justice Scalia, writing

for the Court, explained that “taking action, unrelated to the objectives of the

authorized intrusion, which exposed to view concealed portions of the apartment

or its contents, did produce a new invasion of respondent’s privacy unjustified by

the exigent circumstance that validated the entry.” 480 U.S. 321, 325 (1987). Be-

cause the officer lacked “probable cause to believe that the equipment was stolen,”

the action fell outside plain-view doctrine. Id. at 326.

266. 738 F.2d 538 (2d Cir. 1984).

267. Id. at 541; see also United States v. Agapito, 620 F.2d 324 (2d Cir 1980)

(listening by placing one’s ear against an adjoining door does not violate the

Fourth Amendment), cert. denied, 449 U.S. 834 (1980).

268. Mankani, 738 F.2d at 541.

269. Id. at 543; see also 1

AYNE

AVE

, S

EARCH AND

EIZURE

: A T

REATISE ON

THE

OURTH

MENDMENT

§ 2.2, at 270–72 (1st ed. 1978).

270. Hoffa v. United States, 385 U.S. 293, 303 (1966).

271. Lopez v. United States, 373 U.S. 427, 466 (1963) (Brennan, J., dissent-

ing); see also discussion infra Part III(F)(2).

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protected. But if a search involved physical manipulation, such as

opening a bag, squeezing it, or feeling its contours, then the ordi-

nary senses test did not apply.

272

D. Global Positioning System Technology

GPS technology is similar to the radio frequency beepers used

in Knotts and Karo in that it allows law enforcement to monitor the

movements of one or more persons or objects, from a remote loca-

tion, for some amount of time.

273

But it differs in terms of accuracy,

reliability, the verification required (impacting resources required

for monitoring the device, the likelihood of detection, and the de-

gree of intrusion), the level of detail obtained, and the potential

analytical yield.

274

A brief discussion of these five characteristics

provides context for the types of privacy concerns raised the 2012

case of United States v. Jones.

275

First, GPS devices are more accurate than beepers. GPS can

pinpoint where a tracked device is located to within a few centime-

ters.

276

In contrast, radio-frequency transmitters appear to provide

272. See, e.g., Bond v. United States, 529 U.S. 334, 337 (2000) (responding to

the government’s claim “that by exposing his bag to the public, petitioner lost a

reasonable expectation that his bag would not be physically manipulated,” by not-

ing that Ciraolo and Riley “involved only visual, as opposed to tactile, observation.”).

273. See Rene

e McDonald Hutchins, Tied Up in Knots? GPS Technology and the

Fourth Amendment, 55

UCLA L. R

. 409, 415 (2007).

274. See generally April A. Otterburg, Note, GPS Tracking Technology: The Case

for Revisiting Knotts and Shifting the Supreme Court’s Theory of the Public Space Under the

Fourth Amendment, 46

B.C. L. R

. 661, 681–82 (2005) (discussing State v. Jackson,

76 P.3d 217 (Wash. 2003)); Hutchins, supra note 273, at 418–19; Brief of Appel-

lants at 57, United States v. Jones, 615 F.3d 544 (D.C. Cir. 2010) (No. 08–3030),

2009 WL 3155141 [hereinafter: Appellants’ Brief]; Ian Herbert, Note, Where We Are

with Location Tracking: A Look at the Current Technology and the Implications on Fourth

Amendment Jurisprudence, 16

ERKELEY

J. C

RIM

. L.

442 (2011).

275. United States v. Jones, 132 S. Ct. 945 (2012).

276. Derek Major, Another Great Leap for GPS?, GCN (Feb. 17, 2016), https://

gcn.com/articles/2016/02/17/improved-gps.aspx?s=gcntech_180216. In 1978,

the Department of Defense launched its first GPS satellite. Darren Griffin, How

Does the Global Positioning System Work?,

OCKET

GPSW

ORLD

COM

, http://

www.pocketgpsworld.com/howgpsworks.php (last updated June 26, 2011). By

1994, the system had expanded to include 24 satellites, collectively called NAV-

STAR.

COTT

ACE ET AL

., RAND C

ORP

., T

LOBAL

OSITIONING

YSTEM

: A

SSESS-

ING

ATIONAL

OLICIES

246 (1995). The system now includes approximately 30

satellites that orbit the Earth at an altitude of 20,000 kilometers. How Does GPS

Work?,

HYSICS

ORG

, http://www.physics.org/article-questions.asp?id=55 (last vis-

ited Nov. 19, 2016). Although it initially reserved the system for the military, in

May 2000, the U.S. government opened it to civilian use. Press Release, Office of

the Press Secretary of the White House, Statement by the President Regarding the

United States’ Decision to Stop Degrading Global Positioning System Accuracy

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600 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

only a general location.

277

The distinction means that more accu-

(May 1, 2000), https://clinton4.nara.gov/WH/EOP/OSTP/html/0053_2.html.

The decision proved essential to private sector innovation. By 2003, the technology

had exploded to support a $4.7 billion market.

ATIONAL

ORKRIGHTS

NSTITUTE

OUR

RACKS

: GPS T

RACKING IN THE

ORKPLACE

(2004). Uses ranged from

employers wanting to track their workers by installing GPS chips on vehicles, in

badges, and on phones, to law enforcement using the information as part of crimi-

nal investigations. Id. at 10–15.

NAVSTAR continues to evolve. On February 5, 2016, the Air Force successfully

launched the final GPS IIF satellite. Space Segment,

GPS.

GOV

, http://www.gps.gov/

systems/gps/space/#IIF (last updated Oct. 4, 2016). The solicitation process for

GPS III space vehicles, moving NAVSTAR to its third iteration, has already begun.

Space and Missile Systems Center, SMC Releases RFP for GPS III Space Vehicles 11+

Phase 1 Production Readiness Feasibility Assessment,

ORCE

PACE

OMMAND

(Jan. 8,

2016), http://www.afspc.af.mil/News/Article-Display/Article/730920/smc-releas

es-rfp-for-gps-iii-space-vehicles-11-phase-1-production-readiness-fea.

NAVSTAR has proven important not just within the United States but world-

wide. The only current global alternative is the Russian-Operated Global Naviga-

tion Satellite System (GLONASS). Chris Bergin & William Graham, Soyuz 2-1B

Launches Latest GLONASS-M Spacecraft,

NASAS

PACEFLIGHT

COM

(Feb. 6, 2016),

http://www.nasaspaceflight.com/2016/02/soyuz-2-1b-latest-glonass-m-spacecraft/.

The European Union recently initiated a navigation satellite system for Europe,

entitled Galileo, which is interoperable with NAVSTAR and GLONASS. What Is

Galileo?,

UROPEAN

PACE

GENCY

, http://www.esa.int/Our_Activities/Navigation/

Galileo/What_is_Galileo

(

last updated Dec.18, 2015). The EU launched the first

two satellites in October 2012 to validate the concept. Two more followed nearly a

year later. Four pairs of fully operational capability satellites have since been

launched, through December 17, 2015. When fully deployed, the system will have

24 operational satellites positioned in three circular medium earth orbit planes,

approximately 23,000 kilometers above the surface. They are expected to be availa-

ble by the end of 2016, with completion slotted for 2020. Id. The People’s Repub-

lic of China, which currently operates the regional Beidou Navigation Satellite

System, plans to expand it into a global system by 2020. El Borromeo, China to

Unveil 40 Beidou Navigation Satellites in Five Years: Spokesperson,

IBADA

(Feb. 6,

2016), http://en.yibada.com/articles/102630/20160206/china-unveil-40-beidou-

navigation-satellites-five-years-spokesperson.htm. India, Japan, and France all run

or are developing regional systems. Deepu Madhavan, Say Goodbye to GPS! India’s

All Set to Switch to the Desi Navigation System, IRNSS,

NDIA

IMES

(Dec. 8, 2015),

http://www.indiatimes.com/news/india/say-goodbye-to-gps-india-s-all-set-to-switch

-to-the-desi-navigation-system-called-indian-regional-navigation-satellite-system-

irnss-248186.html; What is the Quasi-Zenith Satellite System?,

ATIONAL

PACE

OLICY

ECRETARIAT OF

APAN

, http://qzss.go.jp/en/overview/services/sv02_why.html

(last visited Nov. 19, 2016);

ONBO

HOU

NTERNET OF

HINGS IN THE

LOUD

A M

IDDLEWARE

ERSPECTIVE

130

(2013) (noting that France is developing a re-

gional system).

277. In its reply brief in Karo, the government stated that law enforcement

officers standing on a sidewalk 25-50 feet from a home could tell whether the

beeper was located in the front or back of the home, or on the right or left side.

Clifford S. Fishman, Electronic Tracking Devices and the Fourth Amendment: Knotts,

Karo, and the Questions Still Unanswered, 34

ATH

. U. L. R

277, 282 (1985) (citing

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rate data can be obtained from GPS, providing deeper insight into

the individual or object under surveillance.

Second, GPS data is more reliable: beepers cannot be used in

inclement weather, whereas GPS operates regardless of whether it is

sunny, raining, or the middle of a blizzard.

278

Thus for GPS, the

amount (and quality) of data is not limited by natural conditions.

Third, the two systems depart in what must be done to verify

the information. GPS allows for law enforcement to be located vir-

tually anywhere.

279

For a radio-frequency transmitter, the police

have to be relatively nearby.

280

This has several implications.

For one, it takes a considerable amount of manpower, equip-

ment, and resources to conduct surveillance using a beeper,

whereas the costs for using GPS are lower.

281

From a resource per-

spective, therefore, law enforcement officers could entertain a

lower level of individual suspicion before placing an individual

under surveillance using GPS than might otherwise be the case for

their decision to employ radio-frequency chips. Similarly, using

GPS, they could choose to put multiple people under surveillance

simultaneously, resulting in greater inroads into privacy because of

the lowered resource commitment entailed.

For another, since police need to be nearby, drivers are more

likely to be able to detect police tracking a beeper than police fol-

lowing GPS data.

282

The absence of any observable government

presence may have implications for the relationship of citizens to

the government, as the surreptitious nature of the surveillance

raises question about the extent of government activity.

283

To the

Reply Brief for Petitioners at 9 n.6, United States v. Karo, 468 U.S. 705 (1984) (No.

83–850)).

278. Hutchins, supra note 273, at 418; Appellants’ Brief, supra note 274, at 57.

279. Scott W. Turner, GPS Surveillance, the Right to Privacy, and the Fourth

Amendment, 40

OLO

. L

55, 57 (2011) (“Much like [radio beepers] . . . a GPS

unit can be placed on an object and observed as it is being moved. The observation

can be continuous. However, because of the technology, a person does not have to

be nearby to obtain its signal. The movement of an individual being tracked

through a GPS device can be observed by someone sitting at a computer from

essentially anywhere.”).

280. In Karo, the government stated that under ordinary conditions on the

open road, the signal could be monitored 2-4 miles away, and up to 20 miles in the

air. Once a beeper went inside premises, however, it was not always possible to

identify its location. Fishman, supra note 277, at 282 (citing Reply Brief, supra note

277, at 8 n.6).

281. Appellants’ Brief, supra note 274, at 57.

282. Id.

283. See, e.g., Herbert, supra note 274, at 458–60 (discussing a number of inci-

dents where individuals discovered FBI GPS surveillance devices on their cars).

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602 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

extent that law enforcement agencies state that any information

about GPS devices or tracking technologies is “law enforcement

sensitive” (and thus refuse to release any information publicly

about their use of the technologies), the concern increases.

284

In addition, because radio-frequency enabled transmitters re-

quire the police to be in close proximity, officers cannot easily fol-

low the person or object onto private land, within gated

communities, or across borders.

285

In contrast, a GPS device may be

carried virtually anywhere, including the most intimate spheres of

personal and family life, without the target knowing that the infor-

mation is being collected and monitored by the government. GPS

data obtained on multiple people also can be correlated, showing

others with whom the individual is sharing those spaces, generating

insight into intimate relationships.

Fourth, GPS chips provide more detailed information than can

be obtained from beepers.

286

GPS generates location data on a sec-

ond-by-second basis. And it is automated, so the government can

turn it on and then more or less ignore it. It can record informa-

tion indefinitely, until law enforcement officials (or anyone else

with access to the system) would like to look at the data, or to find

(in real time) the person or object being tracked.

287

In contrast, in

addition to being less accurate than GPS chips, beepers only send

out periodic signals, generating smaller amounts of information.

Someone has to be present to pick up the information, so less of it

is captured. And beepers are only good for as long as their battery

has power.

Fifth, because GPS data is detailed and digital, law enforce-

ment can more easily combine it with other data, and synthesize

and analyze an individual’s movement over lengthy periods,

288

even

predicting, based on pattern analytics, the individual’s future move-

ments. This is more than just ordinary sensory perception, to which

Fourth Amendment doctrine clings. It introduces a different form

of knowledge acquisition than is at stake in radio-frequency ena-

bled transmitter tracking.

289

284. Id. at 459–61.

285. Appellants’ Brief, supra note 274, at 57.

286. Id.

287. See Hutchins, supra note 273, at 458; see also Appellants’ Brief, supra note

274, at 57, 64.

288. Appellants’ Brief, supra note 274, at 57.

289. See, e.g., State v. Jackson, 76 P.3d 217, 223 (Wash. 2003) (“We perceive a

difference between the kind of uninterrupted, 24-hour a day surveillance possible

through use of a GPS device, which does not depend upon whether an officer

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In sum, compared to beepers, GPS technology is more accu-

rate and more reliable. It requires fewer resources and is harder to

detect. It provides enormous detail and can be analyzed and com-

bined with other information to generate further insight into sus-

pects’ lives. Law enforcement has therefore become increasingly

reliant on GPS data for investigations.

290

An increasing number of

cases are therefore coming before the courts, challenging the war-

rantless use of GPS technology.

Much like the Court in Olmstead, when confronted by tele-

phone communications, a number of lower courts initially treated

the placement of GPS chips on vehicles consistent with the Knotts

framework, finding that it did not constitute a search.

291

Satellite-

based tracking fell on the same side of the line as surveillance cam-

eras and satellite imaging.

292

A few courts, however, disagreed.

293

In 2003, the state of Wash-

ington determined that, unlike binoculars or a flashlight, GPS sys-

tems did not merely enhance the natural senses.

294

They provided a

substitute for visual tracking, resulting in significant intrusions into

individuals’ private affairs.

295

The text of the Washington state con-

stitution mattered: “no person shall be disturbed in his private af-

could in fact have maintained visual contact over the tracking period, and an of-

ficer’s use of binoculars or a flashlight to augment his or her senses.”).

290. See

LISON

M. S

MITH

, C

ONG

. R

ESEARCH

ERV

., R41663, L

NFORCEMENT

SE OF

LOBAL

OSITION

(GPS) D

EVICES TO

ONITOR

OTOR

EHICLES

: F

OURTH

MENDMENT

ONSIDERATIONS

1–3

(2011).

291. See, e.g., United States v. Cuevas-Perez, 640 F.3d 272, 273, 275–76 (7th

Cir. 2011) (finding 60-hour GPS surveillance outside the protections of the Fourth

Amendment), cert. granted and judgment vacated, 132 S. Ct. 1534 (2012); United

States v. Pineda-Moreno, 591 F.3d 1212, 1217 (9th Cir. 2010), cert. granted and judg-

ment vacated, 132 S. Ct. 1533 (2012); United States v. Marquez, 605 F.3d 604,

609–10 (8th Cir. 2010); United States v. Garcia, 474 F.3d 994, 997 (7th Cir. 2007)

(holding that GPS simply uses technology to substitute for trailing a car on a pub-

lic street, which does not amount to a search within the meaning of the Fourth

Amendment); United States v. McIver, 186 F.3d 1119, 1125 (9th Cir. 1999), cert.

denied, 528 U.S. 1177 (2000); United States v. Moran, 349 F. Supp. 2d 425, 467

(N.D.N.Y. 2005) (holding use of a GPS device to be within the automobile excep-

tion); Osburn v. State, 44 P.3d 523 (Nev. 2002) (applying State constitution).

292. Garcia, 474 F.3d at 997.

293. See, e.g., United States v. Maynard, 615 F.3d 544, 555–56 (D.C. Cir. 2010)

(tracking movements for twenty-four hours a day for four weeks by GPS is a

search); People v. Lacey, No. 2463N/02, 787 N.Y.S.2d 680, 2004 WL 1040676, at *8

(Nassau Cty. Ct. N.Y. May 6, 2004) (unpublished table opinion), aff’d, 787 N.Y.S.2d

680 (N.Y. App. Div. 2009); State v. Campbell, 759 P.2d 1040 (Or. 1988) (applying

State constitution and finding that use of radio transmitter to locate automobile

was a search); Jackson, 76 P.3d 217.

294. Jackson, 76 P.3d at 223.

295. Id.

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fairs, or his home invaded, without authority of law.”

296

The

Washington Supreme Court noted that the insight into individuals’

private lives that can be gleaned by GPS data is substantial:

For example, the device can provide a detailed record of travel

to doctors’ offices, banks, gambling casinos, tanning salons,

places of worship, political party meetings, bars, grocery stores,

exercise gyms, places where children are dropped off for

school, play, or day care, the upper scale restaurant and the

fast food restaurant, the strip club, the opera, the baseball

game, the “wrong” side of town, the family planning clinic, the

labor rally.

297

Such information could provide details on citizens’ preferences, as-

sociations, and predilections, drawing a “detailed picture of one’s

life.”

298

The Washington court was not alone. In People v. Lacey, a New

York court similarly determined that law enforcement use of a GPS

device required a warrant.

299

In that case, a woman returned home

to find two men at her back door.

300

She chased them and took

down the license plate of the black 1996 Mitsubishi Eclipse they

were driving.

301

Another incident in the same county occurred in-

volving a black Mitsubishi, (along with a series of other local burgla-

ries), prompting the detective in charge of the investigation to

request permission from his lieutenant to place a GPS device on the

car.

302

The police then tracked the vehicle, correlated its location

with a number of burglaries, and arrested the owner in the middle

of a heist.

303

296.

ASH

. C

ONST

art. 1, § 7, construed in Jackson, 76 P.3d at 222 (“The in-

quiry under article 1, section 7 is broader than under the Fourth Amendment to

the United States Constitution.”).

297. Jackson, 76 P.3d at 223.

298. Id.

299. People v. Lacey, No. 2463N/02, 787 N.Y.S.2d 680, 2004 WL 1040676, at

*8 (Nassau Cty. Ct. N.Y. May 6, 2004) (unpublished table opinion), aff’d, 787

N.Y.S.2d 680 (N.Y. App. Div. 2009).

300. Id. at *1.

301. Id.

302. Id. at *1–*2.

303. Id. at *3. As the question of whether the Fourth Amendment applied to

GPS devices was a case of first impression for New York, the court looked to other

state cases for guidance. Id. at *5–*6, (citing, among others, State v. Jackson, 76

P.3d 217 (Wash. 2003); State v. Campbell, 759 P.2d 1040 (Or. 1988); Johnson v.

State, 492 So. 2d 693, 694 (Fla. Dist. Ct. App. 1986) (holding that a beeper on a

plane was “tantamount to an illegal entry and beyond the scope of the warrant”)).

However, the court in Lacey mentioned, although it did not discuss in detail, a

number of cases that went the other way. 2004 WL 1040676, at *6–*7 (citing,

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The court balked at the possibility that the police could place

GPS devices on vehicles and follow them around indefinitely with-

out probable cause. “The citizens of New York,” Judge Joseph

Calabrese stated, “have the right to be free in their property, espe-

cially in light of technological advances which have and continue to

diminish this privacy.”

304

If it were a telephone communication, the

police would have to obtain a warrant: “While the telegraph has

become a relic of the past, cellular technology has become the fu-

ture.”

305

The judge was concerned about what the future might

hold:

At this time, more than ever, individuals must be given the con-

stitutional protections necessary to their continued unfettered

freedom from a “big brother” society. Other than in the most

exigent circumstances, a person must feel secure that his or

her every movement will not be tracked except upon a warrant

based on probable cause establishing that such person has

been or is about to commit a crime. Technology cannot abro-

gate our constitutional protections.

306

In Lacey, Judge Calabrese boldly addressed the key question—an

opportunity the Supreme Court failed to take, more than a decade

later.

307

In United States v. Jones, the Court considered a GPS chip that

the police placed on the car of a suspected drug dealer’s wife and

monitored for 28 days.

308

Justice Scalia, writing for the Court, stated

that the placement of the chip on the car, which occurred outside

the period allowed by the warrant, amounted to a trespass.

309

Scalia

distinguished Karo, noting that what made the placement of the

among others, State v. Clifton, 580 S.E.2d 40 (N.C. Ct. App. 2003) (upholding the

constitutionality of law enforcement use of a manufacturer-installed GPS); White-

head v. State, 574 S.E.2d 351 (Ga. Ct. App. 2002) (affirming conviction where po-

lice placed a GPS device on an informer’s car, with the informer’s consent)).

304. Lacey, 2004 WL 1040676, at *8.

305. Id.

306. Id.

307. See United States v. Jones, 132 S. Ct. 945, 954 (2012). In addition to a

number of state court decisions, a number of state legislatures have taken steps to

prohibit the warrantless use of electronic tracking devices; see also Herbert, supra

note 274, at 445 nn.12–14 (citing laws passed in Utah, Florida, South Carolina,

Oklahoma, Hawaii, Pennsylvania, and California).

308. Jones, 132 S. Ct. at 948.

309. Id. at 352; see also Johnson v. State, 492 So. 2d 693, 694 (Fla. Dist. Ct.

App. 1986) (holding that installation of a beeper inside a plane amounted to an

illegal entry and thus a violation of the Fourth Amendment); People v. Oates, 698

P.2d 811, 816 (Colo. 1985) (en banc) (applying State constitution and finding that

placement of a beeper inside a container of chemicals after the defendant had

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transmitter in the container of ether legal was that it was placed

into the device before the target of the surveillance had possession.

In contrast, the car was already in Antoine Jones’s wife’s possession

when law enforcement attached the device.

310

He reasoned that the

case was entirely consistent with Knotts; the holding in Knotts merely

recognized that the target had no reasonable expectation of pri-

vacy, per Katz, in the location of the automobile carrying the

container of chloroform.

311

Katz, however, had to be understood as

adding to, not substituting for, the common law trespassory test. As

in Karo, “The beeper had been placed in the container before it

came into Knotts’ possession, with the consent of the then-

owner.”

312

Scalia reiterated that naked eye doctrine controls public space.

“This Court has to date not deviated from the understanding that

mere visual observation does not constitute a search.”

313

What one

could ascertain from ordinary senses, in public, lay beyond the

reach of the Fourth Amendment. He went on to reject any privacy

interest in the length of the surveillance. “[E]ven assuming that the

concurrence is correct to say that ‘[t]raditional surveillance’ of

Jones for a 4-week period ‘would have required a large team of

agents, multiple vehicles, and perhaps aerial assistance,’ . . . our

cases suggest that such visual observation is constitutionally permis-

sible.”

314

At the same time, he admitted that the Court might have

to grapple with the implications of lengthy surveillance in the fu-

ture: “It may be that achieving the same result through electronic

means, without an accompanying trespass, is an unconstitutional in-

vasion of privacy, but the present case does not require us to answer

that question.”

315

While Scalia sidestepped the hard questions presented by per-

sistent monitoring, Justice Alito, joined in his concurrence by Jus-

tice Ginsburg, Justice Breyer, and Justice Kagan, did not.

316

Alito

began by drawing a parallel between the majority in Jones and the

Court in Silverman, which (consistent with Olmstead) had required

“unauthorized physical penetration” for Fourth Amendment inter-

partially purchased and taken possession of the materials amounted to a warrant-

less search).

310. Jones, 132 S. Ct. at 952.

311. Id. at 951–52.

312. Id. at 952.

313. Id. at 953.

314. Id. at 953–54 (citation omitted) (quoting id. at 963 (Alito, J.,

concurring)).

315. Id. at 954.

316. Jones, 132 S. Ct. at 958 (Alito, J., concurring).

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ests to arise.

317

The Jones majority similarly focused on physical in-

trusion, despite the fact that, post-Katz, the trespass rule no longer

applied.

318

For Alito, the key question was whether the long-term

monitoring of the car violated the respondent’s reasonable expecta-

tion of privacy.

319

He concluded that it did.

320

Technology, Alito

averred, can change expectations.

Recent years have seen the emergence of many new devices

that permit the monitoring of a person’s movements. In some

locales, closed-circuit television video monitoring is becoming

ubiquitous. On toll roads, automatic toll collection systems cre-

ate a precise record of the movements of motorists who choose

to make use of that convenience. Many motorists purchase cars

that are equipped with devices that permit a central station to

ascertain the car’s location at any time . . . . Perhaps most sig-

nificant, cell phones and other wireless devices now permit

wireless carriers to track and record the location of users.

321

Limited resources previously played a role in restricting incursions

into privacy. “In the pre-computer age,” Alito explained, “the great-

est protections of privacy were neither constitutional nor statutory,

but practical. Traditional surveillance for any extended period of

time was difficult and costly and therefore rarely undertaken.”

322

Only an important investigation would have used such means.

323

GPS devices, however, have made “long-term monitoring relatively

easy and cheap.”

324

Short-term monitoring using the chips might

be one thing, “But the use of longer term GPS monitoring in inves-

tigations of most offenses impinges on expectations of privacy.”

325

For those offenses, society did not reasonably expect that law en-

forcement would “secretly monitor and catalogue every single

movement of an individual’s car for a very long period.”

326

Four

weeks was too long.

317. Id. at 959 (citing Silverman v. United States, 365 U.S. 505, 509 (1961)).

318. Id. at 959–60 (citing Rakas v. Illinois, 439 U.S. 128, 143 (1978); Katz v.

United States, 389 U.S. 347, 353 (1967) (finding the trespass theory “no longer

controlling”)).

319. Id. at 958.

320. Id. at 964.

321. Id. at 963.

322. Jones, 132 S. Ct. at 963 (Alito, J., concurring).

323. Id. at 963–64.

324. Id. at 964.

325. Id.

326. Id.

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608 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

Justice Sotomayor, in a separate concurrence, agreed.

327

technology advances, the government will have greater access to ge-

olocational data.

328

In contrast to Scalia, Sotomayor argued that

longer-term monitoring impinges on expectations of privacy.

329

Lo-

cation tracking implicates other rights as well, chilling associational

and expressive freedoms.

330

“[T]he Government’s unrestrained

power to assemble data that reveal private aspects of identity,”

moreover, “is susceptible to abuse.”

331

The privacy interests at stake

were considerable. People did not “reasonably expect that their

movements will be recorded and aggregated in a manner that en-

ables the Government to ascertain, more or less at will, their politi-

cal and religious beliefs, sexual habits, and so on.”

332

Such a tool, in

the hands of the Executive and without any oversight, would be ripe

for abuse.

333

While the majority decided the case on grounds of trespass,

what has come to be understood as the shadow majority in Jones

(the five Justices joining the Alito and Sotomayor concurrences),

like the dissents in Olmstead and Goldman, and the Court in

Silverman, signaled a growing concern about the impact of new

technology on privacy interests protected under the Fourth

Amendment.

334

327. See id. at 955 (Sotomayor, J., concurring).

328. See Jones, 132 S. Ct. at 955 (Sotomayor, J., concurring).

329. Id. at 955.

330. Id. at 955–56.

331. Id. at 956.

332. Id.

333. Id.

334. The Court has not limited the private/public distinction to land. In 1927

United States v. Lee considered the use of a searchlight that uncovered cases of li-

quor on a boat. 274 U.S. 559, 562–63 (1927). The Supreme Court determined:

[N]o search on the high seas is shown. The testimony of the boatswain shows

that he used a searchlight. It is not shown that there was any exploration be-

low decks or under hatches. For aught that appears, the cases of liquor were

on deck and, like the defendants, were discovered before the motorboat was

boarded. Such use of a searchlight is comparable to the use of a marine glass

or field glass. It is not prohibited by the Constitution.

Id. at 563. Justice Brandeis, writing for the Court, was careful to note that the cases

of liquor were simply sitting on the deck and not located below, so no actual entry

had to occur for the officers to ascertain that the vessel was carrying contraband.

Id. Following Katz, the private/public distinction persisted for searches conducted

on the high seas. Like the location of the buildings on the Dow Chemical’s cam-

pus, the location of a vessel in the ocean did not “provide the setting for those

intimate activities that the [Fourth] Amendment is intended to shelter from gov-

ernment interference or surveillance.” Oliver v. United States, 466 U.S. 170, 179

(1984); see also Jason R. Crance & Mike Mastry, Fourth Amendment Privacy Rights at

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 609

E. Enhanced Detection

Starting in the early 1990s, new technologies and techniques

that enhanced the human senses, such as thermal imaging, or the

use of narcotics dogs, began to make their way onto the Court’s

docket. Despite the movement in Katz to determining privacy from

the perspective of the individual (rather than the specific places

being protected), the Court continued to rely upon the territorial

private/public distinction, with the line drawn at the curtilage of

the home.

In 1991, for instance, an agent from the U.S. Department of

the Interior suspected that an Oregon resident, Danny Kyllo, was

growing marijuana in his home.

335

Knowing that successfully grow-

ing the plant indoors required the use of high intensity lamps, the

Sea and Governmental Use of Vessel Monitoring Systems: There’s Something Fishy About

This, 22 J.

NVTL

. L. & L

ITIG

231, 246 (2007). Arguments regarding the navigation

of a vessel paralleled the doctrinal approach to observing a car as it traversed pub-

lic thoroughfares. See United States v. Knotts, 460 U.S. 276, 281 (1983) (quoting

Cardwell v. Lewis, 417 U.S. 583, 590 (1974) (Cars have “little capacity for escaping

public scrutiny” when traveling on “public thoroughfares where both its occupants

and its contents are in plain view.”)). Just as the public could observe a car, so, too,

could citizens see boats and ships on the open water. Combined with the nature of

commercial fishing, a lower expectation of privacy held. Why should government

regulators or law enforcement officers be subject to different standards?

Like radio-frequency-enabled transmitters, vessel monitoring systems (VMS)

do not provide information located within the vessel, or below deck—making a

Fourth Amendment search claim, under the current doctrine, somewhat question-

able. Lower courts are divided on whether, and under what circumstances, a cap-

tain of a vessel has a reasonable expectation of privacy in what occurs on different

parts of the vessel. Crance & Mastry, supra, at 247–48. The Fifth Circuit has

adopted an approach that mirrors the distinction between open fields and matters

located within the curtilage of the home. Since the Coast Guard can conduct ad-

ministrative inspections of public areas without probable cause and a warrant, the

captain of a vessel has no reasonable expectation of privacy in the public areas of

the vessel. See id. at 247. In United States v. Freeman, the Coast Guard located the

vessel by means of radar, after which it found more than 41,000 pounds of mari-

juana on board. 660 F.2d 1030, 1031–34 (5th Cir. 1981), discussed in Crance &

Mastry, supra, at 247. In contrast to the Fifth Circuit, the First Circuit considers that

the captain has a reasonable expectation of privacy to the extent that it “derives

from his custodial responsibility for the ship, his associated legal power to exclude

interlopers from unauthorized entry . . . and the doctrines of admiralty, which

grant the captain (as well as the owner) a legal identity of interest with the vessel.”

United States v. Cardona-Sandoval, 6 F.3d 15, 21 (1st Cir. 1993), quoted in Crance

& Mastry, supra, at 247–48. For non-public areas of the vessel, the circuits agree

that those on board do have a reasonable expectation of privacy. See, e.g., United

States v. DeWeese, 632 F.2d 1267 (5th Cir. 1980), cited in Crance & Mastry, supra, at

248.

335. Kyllo v. United States, 533 U.S. 27, 29 (2001).

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610 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

agent directed a thermal scanner at Kyllo’s triplex to detect the

level of infrared radiation emanating from the structure.

336

The

scan showed a hot spot along the roof over the garage.

337

Based on

the results of the test, tips from informants, and Kyllo’s utility bills,

a federal magistrate judge issued a warrant for a search that yielded

100 marijuana plants.

338

Justice Scalia, writing for the Court, relied on the walls of the

home and the degree to which the observer’s senses had been en-

hanced beyond normal human abilities, to extend Fourth Amend-

ment protections to thermal searches. “The present case,” he wrote,

“involves officers on a public street engaged in more than naked-eye

surveillance of a home.”

339

Scalia acknowledged, “It would be foolish

to contend that the degree of privacy secured to citizens by the

Fourth Amendment has been entirely unaffected by the advance of

technology.”

340

Aircraft had exposed the top of peoples’ homes to

public view—including portions of the curtilage once considered

private. Thermal imaging raised the question of whether limits ex-

isted on the “power of technology to shrink the realm of guaran-

teed privacy.”

341

Detecting activity inside the home intruded upon a

rule in operation since the founding of the country. “Where, as

here, the Government uses a device that is not in general public

use, to explore details of the home that would previously have been

unknowable without physical intrusion, the surveillance is a ‘search’

and is presumptively unreasonable without a warrant.”

342

In 2013, the Court considered another sensory enhancement:

this time, whether the use of canines outside of a home, to detect

narcotics inside the structure, amounted to a search.

343

The Court

had previously determined that the use of dogs outside of cars, to

detect narcotics inside the vehicle, was not a search.

344

In Florida v.

Jardines, the Miami-Dade Police Department received a tip that Joe-

336. Id.

337. Id. at 30.

338. Id.

339. Id. at 33 (emphasis added).

340. Id. at 33–34.

341. Kyllo, 533 U.S. at 34.

342. Id. at 40.

343. Florida v. Jardines, 133 S. Ct. 1409, 1413 (2013).

344. See Illinois v. Caballes, 543 U.S. 405, 410 (2005); see also United States v.

Place, 462 U.S. 696, 707 (1983) (police exposing luggage at airport to drug-sniffing

dog was not a search); Donald A. Dripps, Perspectives on the Fourth Amendment Forty

Years Later: Toward the Realization of an Inclusive Regulatory Model, 100

INN

. L. R

1885, 1906–07 (2016) (discussing Caballes and Jardines).

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 611

lis Jardines was growing marijuana in his home.

345

Two police of-

ficers, accompanied by a drug-sniffing dog, went up onto Jardines’s

front porch.

346

On the basis of the dog’s positive response, as well

as the tip, the police obtained a warrant to search the home and

found cannabis.

347

Justice Scalia, writing for the Court, repeatedly emphasized the

territorial nature of the Fourth Amendment. “The officers were

gathering information in an area belonging to Jardines and imme-

diately surrounding his house—in the curtilage of the house,” he

wrote.

348

“[T]hey gathered that information by physically entering

and occupying the area.”

349

For Scalia, the physical property proved

central: “the home is first among equals.”

350

Once establishing the home as “a constitutionally protected

area,” Scalia turned to whether an “unlicensed physical intrusion”

had occurred.

351

The naked eye, again, figured largely: “While law

enforcement officers need not ‘shield their eyes’ when passing by

the home ‘on public thoroughfares,’ an officer’s leave to gather in-

formation is sharply circumscribed when he steps off those thor-

oughfares.”

352

In Ciraolo, there had been no physical intrusion of

the property.

353

The fact that the police in Jardines had used a

trained animal appears to have mattered little, as the effect was the

same: it altered law enforcement’s ability to detect information

about a protected area that was not evident from the use of ordi-

nary senses.

In her concurring opinion, Justice Kagan, joined by Justice

Ginsburg and Justice Sotomayor, emphasized the extent to which

the canine unit had augmented natural human abilities. “Here,”

she wrote, “police officers came to Joelis Jardines’ door with a

super-sensitive instrument, which they deployed to detect things in-

side that they could not perceive unassisted.”

354

Not only was the

use of a highly-trained dog without a warrant a violation of the

Fourth Amendment, but if the officer had used “super-high-pow-

ered binoculars” to look through a window, that, too, could fall

345. 133 S. Ct. at 1413.

346. Id.

347. Id.

348. Id at 1414.

349. Id.

350. Id.

351. Jardines, 133 S. Ct. at 1415.

352. Id. (quoting California v. Ciraolo, 476 U.S. 207, 213 (1986)) (citation

omitted).

353. Id.

354. Id. at 1418 (Kagan, J., concurring).

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612 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

outside constitutional requirements.

355

Kagan noted the “firm” and

“bright line” that marked “the entrance to the house,” emphasizing

the private/public distinction.

356

Even the dissent turned to some extent upon whether the of-

ficer’s ordinary senses, outside the curtilage of the home, would

suffice. Justice Alito, joined by Chief Justice Roberts, Justice Ken-

nedy, and Justice Breyer, criticized the Court for “fail[ing] to men-

tion that, while [one detective] apparently did not personally smell

the odor of marijuana coming from the house, another officer who

subsequently stood on the front porch . . . did notice that smell and

was able to identify it.”

357

F. Technological Challenges to the Private/Public Distinction

Fourth Amendment doctrine has long struggled with how to

integrate new technologies into the private/public distinction. Per-

haps nowhere are its failings clearer than in the realm of location

tracking.

358

Two elements are now coming together that undermine the

traditional divide. First, the proliferation of tracking technologies

means that enormous amounts of locational data are being gener-

ated, providing detailed pictures of citizens’ lives. Second, the pri-

vate/public distinction in Fourth Amendment doctrine ignores the

possibility that the length of observation, the recording of the information,

or the analysis of data obtained from the public domain could trig-

ger a new privacy interests.

The basic argument is that if privacy is not implicated at the

front end—i.e., the moment an individual sees or hears what a per-

son says or does in public, or reads an individual’s documents or

papers that are in the public domain—then the length of time that

the person is placed under observation, whether the government

records the information that is being generated, and whether the

government later analyzes the data (potentially in combination with

other information) does not give rise to any new privacy right. Zero

355. Id. (distinguishing the scenario from delivering the mail or distributing

campaign flyers).

356. Id. at 1419.

357. Jardines, 133 S. Ct. at 1421 (Alito, J., dissenting).

358. Various commentators directly challenge the private/public distinction.

See, e.g., Sean K. Driscoll, “The Lady of the House” vs. a Man with a Gun: Applying

Kyllo to Gun-Scanning Technology, 62

ATH

. U. L. R

601, 604–05 (2013) (discuss-

ing the Fourth Amendment implications of firearms scanners using Terahertz

Imaging Detection).

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 613

plus zero is still zero. Actions in public simply are unprotected by

the Fourth Amendment.

This approach is deeply problematic. Locational data, col-

lected in bulk, yields deep insight into individuals’ lives. Continued

reliance on the private/public distinction fails to capture the inter-

ests at stake in public monitoring, and in the collection and analysis

of locational data.

1. Digital Tracking

The number of ways that new technologies give others the abil-

ity to follow individuals is staggering. WiFi and Bluetooth signals;

GPS chips; vessel monitoring systems; RFID tags; automated license

plate readers; network connection data; international mobile sub-

scriber identity catchers; Internet protocol databases; financial

transactions; consumer purchases; closed circuit televisions; remote

biometric identification; and unmanned aerial systems provide just

some examples.

359

Tracking has become such an intrinsic feature of

modern life that many people do not even realize who is tracing

their footsteps. Even a brief discussion illustrates the depth of pri-

vate information that is available.

Special sensors detect WiFi and Bluetooth-enabled devices,

such as mobile telephones, electronic tablets, and computers, as in-

dividuals move through public space. Industry is capitalizing on this

rich source of data. Companies such as LocationGenius, for in-

stance, guarantee “crowd-sourced scoring and analytics for any loca-

tion”—including retail analytics, audience profiles and impressions,

on-demand real estate data, and data related to entire cities or

counties for use in urban planning, migration, security, and local

law enforcement.

360

LocationGenius generates customer profiles based on data col-

lected by mobile carriers. The company guarantees that the retailer

will instantly know where the customer just was, as well as where

their next stop is likely to be.

361

It uses cellular network and device

data, sensors, beacons, as well as social media data, to populate a

359. Mobile devices, Internet-connected products, and online activity con-

stantly create data, which can be collected not just by the government, but by pri-

vate companies that can then trace where people go, how long they spend in each

location, and who they are with when they do so. See Armina Ligaya, You’re Being

Followed: New Digital Tracking Technologies Keep Tabs on Your Every Move,

INANCIAL

OST

AGAZINE

, May 7, 2014, http://business.financialpost.com/financial-post-

magazine/digital-tracking-privacy?__lsa=0f20-ef2c.

360.

OCATION

ENIUS

, http://locationgenius.com (last visited Nov. 19, 2016).

361. Id.

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614 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

profiling engine that “plugs into postal code data, behavioural

streams, census data, and . . . other in-house and third party

sources,” providing retailers with customers’ household income,

ethnicity, gender, educational level, employment, consumer spend-

ing, and brand preferences.

362

LocationGenius is just one example of a burgeoning industry.

The 2016 global market in consumer location information is esti-

mated to be worth more than $16 billion.

363

Mobile marketing (the

provision of personalized, time- and location-sensitive information

to individuals’ mobile devices to promote goods and services) has

become standard business practice.

364

The number of applications

on a smart phone that collect—and sell—data about the user’s

movements is extraordinary.

365

Facebook, Google, Foursquare, and

Twitter are well known for this. But even seemingly innocuous ap-

plications, like Android’s popular Brightest Flashlight Free, have

tracked and sold users’ location information without their

knowledge.

366

362. Id.; see also Ivor Tossell, Using ‘Remarkable’ Source of Data, Startup Builds

Rich Customer Profiles,

LOBE AND

AIL

, Jan. 6, 2014, http://www.theglobeand

mail.com/report-on-business/small-business/sb-growth/how-a-startup-is-using-lo-

cation-data-to-build-rich-customer-profiles-for-retailers/article16187925/.

363. See Ligaya, supra note 359.

364. See, e.g., Lisa Lacy, Mobile Marketing Trends 2016: 50 Experts on the Future of

Apps, Ads & Search,

INKDEX

(

Jan. 4, 2016), http://www.momentology.com/9031-

mobile-marketing-trends-2016/; William Comcowich, Geolocation: The Newest Move-

ment in Mobile Marketing and Measurement,

YBER

LERT

(Mar. 15, 2014), http://

www.cyberalert.com/blog/index.php/geolocation-the-newest-movement-in-mo-

bile-marketing-and-measurement/; Alan Meyer, Mobile Marketing and Geolocation:

Up Your Effectiveness with Location Targeting,

ARNIVAL

, http://insights.carni

val.io/mobile-marketing-and-geolocation-up-your-effectiveness-with-location-

targeting/ (last visited Nov. 19, 2016); Scott Gerber, 14 Mobile Marketing Trends

That Will Dominate in 2016,

ASHABLE

(Dec. 23, 2015), http://mashable.com/

2015/12/23/mobile-marketing-2016/#boz70c3lZiqp.

365. See, e.g., About Privacy and Location Services for iOS 8 and iOS 9,

PPLE

https://support.apple.com/en-gb/HT203033 (last visited Nov. 19, 2016) (noting

that iOS devices allow maps, camera, weather, traffic, and other apps to use infor-

mation from cellular, WiFi, GPS networks, and Bluetooth, to determine users’ loca-

tion; also explaining that Location Services triggers location-based system services

such as Location-Based Apple Ads, Location Based Alerts, and Share My Location);

see also Sig Ueland, 10 Geolocation Apps for Business,

RACTICAL

COMMERCE

(May 13,

2011), http://www.practicalecommerce.com/articles/2780-10-Geolocation-Apps-

for-Business (describing Google Latitude; Google Maps; Google Buzz; Double

Dutch; Neer; Plancast; Glympse; Foursquare; GroupMe; Hashable; Geoloqi;

LiquidSpace).

366. Kristin Burnham, Location Tracking: 6 Social App Settings to Check,

NFORMA-

TION

EEK

(Aug. 26, 2014, 11:30 AM), http://www.informationweek.com/

software/social/location-tracking-6-social-app-settings-to-check/d/d-id/1306643.

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 615

GPS chips that record locational data also have become inte-

grated into our daily lives. In 1996, the FCC adopted rules (imple-

mented by 2001) that required all mobile telephones to be GPS-

enabled to facilitate emergency services.

367

By 2004, even small car-

riers had to comply.

368

In 2015, the FCC expanded the rule to re-

quire mobile telephone providers to build in the capability to

locate cell phones indoors, including the height above ground, ena-

bling law enforcement to pinpoint the precise location of a mobile

phone inside a home, office building, or other structure.

369

Wire-

less carriers do not inform users of any way to disable this func-

tion.

370

As long as the phone is turned on, service providers can

locate the telephone either through hardware built into the device,

or through examining where it connects to the cell site network.

When NAVSTAR opened to commercial interests in 2000, the

use of GPS expanded beyond mobile telephones to enable such va-

ried services as access to local resources, time synchronization, and

air and ground navigation.

371

The technology is now used by air-

lines, farming, mining, prisons, security companies, hobbyists, and

others to program and track people and objects, and to create vir-

tual borders to monitor people, animals, or objects that enter or

leave pre-set boundaries.

372

367. Revision of the Comm’n’s Rules to Ensure Compatibility with Enhanced

911 Emergency Calling Sys., 11 FCC Rcd. 18676, 18683–84 (1996).

368. 911 Service, 47 C.F.R. § 20.18 (1999); Revision of the Comm’n’s Rules to

Ensure Compatibility with Enhanced 911 Emergency Calling Systems, CC No.

94–102, FCC 02–210, at ¶ 32 (July 26, 2002) (order to stay).

369. Wireless E911 Location Accuracy Requirements, PS No. 07–114, FCC

15–9, at ¶¶ 3, 6 (Jan. 29, 2015) (fourth report and order).

370.

See E911 Compliance FAQs

ERIZON

IRELESS

, http://

www.verizonwireless.com/support/e911-compliance-faqs.

371. See Bradford W. Parkinson, GPS Eyewitness: The Early Years, GPS World 5,

Sept. 9, 1994, pp. 32–45;

ICHAEL

USSELL

& J

AMES

M. H

ASIK

, T

RECISION

EVOLUTION

: GPS

AND THE

UTURE OF

ERIAL

ARFARE

429–41 (2002);

ATIONAL

ESEARCH

OUNCIL

, T

LOBAL

OSITIONING

YSTEM

—A S

HARED

ATIONAL

SSET

ECOMMENDATIONS FOR

ECHNICAL

MPROVEMENTS AND

NHANCEMENTS

(1995); Eva

Marie Dowdell, Note, You Are Here! – Mapping the Boundaries of the Fourth Amendment

with GPS Technology, 32

UTGERS

OMPUTER

& T

ECH

. L. J.

109, 109–10 (2005–2006)

(noting the use of GPS for cellular telephony, access to local resources, time syn-

chronization, emergency services, and navigation); KPMG, Self-driving Cars: The

Next Revolution 34, https://www.kpmg.com/US/en/IssuesAndInsights/Articles-

Publications/Documents/self-driving-cars-next-revolution.pdf.

372. HTG Explains: What Geofencing Is (and Why You Should be Using It),

-G

EEK

, http://www.howtogeek.com/221077/htg-explains-what-geofencing-is-

and-why-you-should-be-using-it/ (last visited Oct. 17, 2016); Lauren Brousell, 5

Things You Need to Know About Geofencing, CIO (Aug. 28, 2013), http://

www.cio.com/article/2383123/mobile/5-things-you-need-to-know-about-geofenc-

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616 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

Vessel Monitoring Systems (VMS) consist of electronic devices

that transmit the location of vessels via satellite link to a land-based

receiver.

373

The Magnuson-Stevens Fishery Conservation and Man-

agement Reauthorization Act of 2006 required that the government

increase VMS data sharing among state and federal agencies.

374

August 9, 2006, the National Marine Fisheries Service published a

regulation requiring that all vessel owners operating in the Gulf of

Mexico outfit their vessels with a VMS unit.

375

The devices must

remain on and able to transmit twenty-four hours a day, regardless

of where the vessel is located and irrespective of whether the vessel

is engaged in commercial fishing. Although supported by environ-

mentalists, the constitutional implications of increased use of VMS

mostly have gone unnoticed.

376

Radio frequency identification (RFID) tags have become more

ubiquitous and sophisticated than the beepers used in the investiga-

ing.html; Creating and Monitoring Geofences,

NDROID

EVELOPERS

http://devel-

oper.android.com/training/location/geofencing.html (last visited Oct. 17, 2016);

Geo-fencing,

HAT

COM

, http://whatis.techtarget.com/definition/geofencing

(last visited Oct. 17, 2016); Geofencing,

ECHOPEDIA

https://www.techopedia.com/

definition/14937/geofencing (last visited Oct. 17, 2016). Because of the detail that

GPS provides, from its inception, it has been accompanied by significant privacy

concerns. See, e.g., David Uris, Big Brother and a Little Black Box: The Effect of Scientific

Evidence on Privacy Rights, 42

ANTA

LARA

L. R

. 995, 1006 (2002) (“[S]keptics

can only hope that these devices do not turn out to be Pandora’s boxes, for ‘the

loss of personal civil liberties always begins with the best intentions of the govern-

ment.’”) (citing Bob Van Voris, Black Box Car Idea Opens Can of Worms,

’

L. J.

June 14, 1999, at A1); Simon Romero, Location Devices’ Use Rises, Prompting Privacy

Concerns,

N.Y. T

IMES

, Mar. 4, 2001, http://www.nytimes.com/2001/03/04/busi-

ness/location-devices-use-rises-prompting-privacy-concerns.html; Petition of the

Cellular Telecommunications Industry Association for a Rulemaking to Establish

Fair Location Information Practices at 4–5, In re Petition for Rulemaking, Nov. 22,

2000; Aaron Reneger, Note, Satellite Tracking and the Right to Privacy, 53

ASTINGS

549 (2002). See also Megha Rjagopalan, Cellphone Companies Will Share Your Loca-

tion Data – Just Not with You,

UBLICA

(June 26, 2012), https://

www.propublica.org/article/cellphone-companies-will-share-your-location-data-

just-not-with-you.

373. Vessel Monitoring System Program—Gulf of Mexico Commercial Reef Fish Fre-

quently Asked Questions,

ATIONAL

ARINE

ISHERIES

ERV

, (Apr. 2007), http://

sero.nmfs.noaa.gov/sustainable_fisheries/faqs/documents/pdfs/gulf_of_mexico/

reef_fish/2012/vms_faqs_041707.pdf; see also Crance & Mastry, supra note 334, at

233.

374. Magnuson-Stevens Fishery Conservation and Management Reauthoriza-

tion Act of 2006, Pub. L. No. 109-479, 120 Stat. 3575 (codified as amended at 16

U.S.C. §§ 1801-1883).

375. Fisheries Amendment 18A, 71 Fed. Reg. 45,428 (Aug. 9, 2006) (codified

at 50 C.F.R. §§ 622, 635).

376. But see Crance & Mastry, supra note 334, at 233–34.

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 617

tions in Knotts and Karo.

377

As small as a grain of rice, they can be

used to track goods,

378

persons,

379

or animals;

380

to collect tolls;

381

to read travel documents;

382

to verify the authenticity of items;

383

time sporting events;

384

or to regulate entry into buildings.

385

Enti-

377. A two-way radio with a microprocessor, the device sends out data that is

picked up by electronic readers or antennas, to identify the location of people,

cars, or objects. Battery-powered RFID chips can typically be read from a range of

300 feet (100 meters) away. RFID Frequently Asked Questions,

RFID J

OURNAL

, https://

www.rfidjournal.com/faq/show?139.

378. See, e.g., Jill Gambon, How to Select the Right RFID Tag,

RFID J

OURNAL

(Oct. 15, 2007), https://www.rfidjournal.com/purchase-access?type=Article

&id=3622&r=%2Farticles%2Fview%3F3622; Claire Swedberg, Meggitt Polymers &

Composites Uses RFID to Track Airline Components, Materials,

RFID J

OURNAL

(Sept. 16,

2016), http://www.rfidjournal.com/articles/view?14984 (reporting that MPC’s

manufacturing plant is using RFID to track its materials during manufacturing).

379. See, e.g., Sam Witt, Is Human Chip Implant Wave of the Future?, CNN, Jan.

14, 1999, available at http://www.cnn.com/TECH/computing/9901/14/chip-

man.idg/; Rory Cellan-Jones, Office Puts Chips Under Staff’s Skin,

BBC N

EWS

(Jan. 29,

2015), http://www.bbc.com/news/technology-31042477; John Brandon, Is There a

Microchip Implant in Your Future?,

EWS

(Aug. 30, 2014), http://www.fox

news.com/tech/2014/08/30/is-there-microchip-implant-in-your-future.html. The

FDA has issued guidance for the implantation of RFID chips in humans. Guidance

for Industry and FDA Staff—Class II Special Controls Guidance Document: Implantable

Radiofrequency Transponder System for Patient Identification and Health Information, U.S.

OOD AND

RUG

DMIN

. C

ENTER FOR

EVICES AND

ADIOLOGICAL

EALTH

(Dec. 10,

2014), http://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/

GuidanceDocuments/ucm072141.htm. Companies sell RFID chips to be embed-

ded in human beings for a range of purposes. See Dangerous things, RFID & NFC

Transponder Implants, available at https://dangerousthings.com/transponders/.

When placed under the skin, they can be used to hack phones or to spread com-

puter viruses. See, e.g., Rose Eveleth, The Man Who Hacks Phones with an Implant

Under his Skin, BBC, May 15, 2017, available at http://www.bbc.com/future/story/

20150515-i-hack-phones-with-touch-alone; Mark Gasson, Human Enhancement:

Could you become infected with a computer virus?, 2010 IEEE International Symposium

on Technology and Society, available at http://ieeexplore.ieee.org/document/

5514651/.

380. Claire Swedberg, RFID Goes to the Dogs,

RFID J

OURNAL

(Aug. 6, 2009)

http://www.rfidjournal.com/articles/view?5108.

381. Laurie Wiegler, Taking a Toll: How RFID is Directing Traffic,

RFID I

NSIDER

(Mar. 6, 2014), http://blog.atlasrfidstore.com/taking-toll-rfid; Claire Swedberg,

RFID Drives Highway Traffic Reports,

RFID J

OURNAL

(Nov. 16, 2004), http://

www.rfidjournal.com/articles/view?1243.

382. Paul Prince, United States Sets Date for E-Passports,

RFID J

OURNAL

(Oct. 25,

2006), http://www.rfidjournal.com/articles/view?1951.

383. Claire Swedberg, RFID Gives Sports Memorabilia Stamp of Authenticity, RFID

OURNAL

(Dec. 21, 2007), http://www.rfidjournal.com/articles/view?3828.

384. Fred O’Connor, RFID Helps the Boston Marathon Run,

ASH

. P

OST

Apr. 9,

2007, http://www.washingtonpost.com/wp-dyn/content/article/2007/04/09/

AR2007040901011.html; Claire Swedberg, New York City Marathon Offers Enhanced

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618 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

ties as disparate as Wal-Mart

386

and the Department of Defense

387

require that vendors use RFID tags to ensure more efficient supply

chain management. In 2015, the global RFID market was worth just

over $10 billion.

388

By 2020, the market is expected to exceed $13

billion.

389

Automated license plate readers (ALPRs) pair fixed, portable,

and mobile cameras with searchable databases.

390

The small, high-

speed cameras, which can capture thousands of car license plates

per minute, can be mounted on police cars or city vehicles, as well

as stationary objects, such as signs, tollbooths, or bridges. They re-

cord the license plate, as well as the date, time, and location of each

car. The information is then fed into a local, state, or regional

database, with differing levels of retention, depending upon the

state.

391

Network-based data also yields locational data. Service provid-

ers record where users’ mobile devices connect to local towers—

and not just when a telephone call is made or a text message is

RFID-enabled Apps, RFID J., July 25, 2011, http://www.rfidjournal.com/articles/

view?8626.

385. Smart Card Technology FAQ,

MART

ARD

LLIANCE

, http://www.smart-

cardalliance.org/smart-cards-faq/.

386. University Alliance, RFID Technology Boosts Walmart’s Supply Chain Manage-

ment,

NIV

S.F.

, http://www.usanfranonline.com/resources/supply-chain-man

agement/rfid-technology-boosts-walmarts-supply-chain-management/#.Vs3L-VKqd

fQ (last visited Oct. 17, 2016).

387. See Samuel Greengard, Re-Evaluating Supply Chain Relationships (Sept. 15,

2014), https://www.rfidjournal.com/purchase-access?type=Article&id=12175&r=

%2Farticles%2Fview%3F12175.

388. Raghu Das and Peter Harrop, RFID Forecasts, Players and Opportunities

2016-2026,

IDT

ECH

(Oct. 2015), http://www.idtechex.com/research/reports/

rfid-forecasts-players-and-opportunities-2016-2026-000451.asp.

389. Id.

390.

IETH

IERLACK

ET AL

., L

ICENSE

LATE

EADERS FOR

NFORCEMENT

(2014), http://www.rand.org/pubs/research_reports/RR467.html.

391. Automated License Plate Recognition,

’

N OF

HIEFS OF

OLICE

http://www.iacp.org/ALPR-FAQs;

. C

IVIL

IBERTIES

NION

, Y

EING

RACKED

: H

ICENSE

LATE

EADERS

EING

SED TO

ECORD

MERICANS

’

OVEMENTS

18 (July 2013), https://www.aclu.org/feature/you-are-being-tracked.

For differing lengths of retention compare Ark. Code (2013) §12-12-1801 to 12-12-

1805 (prohibiting data retention beyond 150 days), Cal. Veh. Code (2011) §2413

(prohibiting the California Highway Patrol from retaining data from a license

plate reader more than 60 days, unless the information is to be used as evidence in

a felony case), Maine (2009), 29-AMRSA §2117-A(2) (setting a 21-day limit on the

retention of data obtained via ALPRs), and Tenn. Code (2014) §55-10-302 (put-

ting a 90 day limit on data retention unless the information is part of an ongoing

investigation).

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 619

received, but constantly, as the user moves through space.

392

The

information provides a picture of where individuals go.

393

The

courts that have confronted the question of historical cell site loca-

tion information (CSLI) have struggled with—and split over—

whether or not such information is protected.

394

In 2015, the

Fourth Circuit held that “the government conducts a search . . .

when it obtains and inspects a cell phone user’s historical CSLI for

an extended period of time.”

395

When the case went en banc, how-

ever, the court reversed its decision.

396

Smith controlled. The Elev-

enth Circuit similarly argued that by using a telephone, mobile

users voluntarily provide “location information to telephone com-

392. Patrick DiJusto, What the N.S.A. Wants to Know About Your Phone Calls,

ORKER

, June 7, 2013, http://www.newyorker.com/tech/elements/what-the-

n-s-a-wants-to-know-about-your-phone-calls.

393. See Stephanie K. Pell & Christopher Soghoian, Can You See Me Now?: To-

ward Reasonable Standards for Law Enforcement Access to Location Data That Congress

Could Enact, 27

ERKELEY

ECH

. L. J.

117, 126-27, 168 (2012).

394. Law enforcement has tried to use the Stored Communications Act, as

well as the Electronic Communications Privacy Act, to obtain this information. Ap-

pellants’ Brief, supra note 274, at 65. A number of courts, looking to the private

nature of the information, the ex parte nature of the proceedings, and the re-

duced resources required, have required that law enforcement first demonstrate

probable cause of a particular crime. See Appellants’ Brief, supra note 274, at 66

(citing In re United States for an Order Directing Provider of Elec. Commun. Serv.

To Disclose Records to the Gov’t, 534 F. Supp. 2d 585, 586–87 (W.D. Pa. 2008)); In

re Application of the United States of America for an Order Authorizing the Instal-

lation and Use of a Pen Register Device, a Trap and Trace Device, and for Geo-

graphic Location Information, 497 F. Supp. 2d 301, 302 (D.P.R. 2007); In re the

Application of the United States of America for an Order Authorizing the Disclo-

sure of Prospective Cell Site Information, 2006 U.S. Dist. LEXIS 73324, at 18, 22

(E.D. Wis. Oct. 6, 2006); In re Application of the United States for an Order Au-

thorizing (1) Installation and Use of a Pen Register and Trap and Trace Device or

Process, (2) Access to Customer Records, and (3) Cell Phone Tracking, 441 F.

Supp. 2d 816, 818–19 (S.D. Tex. 2006); In re United States for an Order for Pro-

spective Cell Site Location Info. on a Certain Cellular Tel., No. 06 CRIM. MISC.01,

2006 WL 468300 (S.D.N.Y. Feb. 28, 2006); In re United States for Orders Authoriz-

ing Installation & Use of Pen Registers & Caller Identification Devices on Tel.

Nos., 416 F. Supp. 2d 390, 392 (D. Md. 2006); In re the Applications of the United

States of America for Order Authorizing the Disclosure of Cell Site Information,

2005 U.S. Dist. LEXIS 43736 (D.D.C. Oct. 26, 2005); In re the Application of the

United States for an Order Authorizing the Release of Prospective Cell Site Infor-

mation, 407 F. Supp. 2d 132 (D.D.C. 2005).

395. United States v. Graham, 796 F.3d 332, 344–45 (4th Cir. 2015), reh’g en

banc granted, 624 F. App’x 75 (4th Cir. 2015).

396. United States v. Graham, No. 12-4659 at *5, (4th Cir. May 31, 2016)

(Hein Online).

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620 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

panies,” removing collection of that data by law enforcement from

Fourth Amendment protections.

397

Myriad other ways of obtaining locational data exist. Cell-site

simulators, known as “IMSI catchers,” can be used to locate mobile

telephones within a particular area.

398

The devices essentially pre-

tend to be local cell towers used by mobile service providers, forc-

ing all telephones in a given area that subscribe to the service to

issue signals that can be used to locate all phones in the area.

399

The location of an aircard—i.e., a cellular modem that attaches to a

computer through the USB port to provide Internet access via a

cellular network—can be obtained through similar means.

400

Law

enforcement is increasingly turning to IMSI catchers to search for

individuals both inside buildings (including homes), as well as in

public.

401

Individuals also can be tracked through databases that map IP

addresses to geographic locations.

402

Financial transactions and

credit card information can be used to place individuals at a partic-

ular location at a particular time.

403

Video cameras, enabled with

remote biometric identification, can track individuals as they move

through public space.

404

Not only are there more of them, but the

397. United States v. Davis, 785 F.3d 498, 512 n. 12 (11th Cir. 2015).

398. See Maryland v. Andrews, 134 A.3d 324, 345 (2016) (holding that the

police violated defendant’s reasonable expectation of privacy under the 4th

Amendment by using real-time cell phone information to find the precise location

of an individual within a home); see also Dan Goodhin, Low-cost IMSI Catcher for 4G/

LTE Networks Tracks Phones’ Precise Locations,

ECHNICA

(Oct. 28, 2015), http://

arstechnica.com/security/2015/10/low-cost-imsi-catcher-for-4glte-networks-track-

phones-precise-locations/; Stingray Tracking Devices: Who’s Got Them?,

ACLU

https://www.aclu.org/map/stingray-tracking-devices-whos-got-them (last visited

Oct. 16, 2016). Note that “Stingray,” made by Harris Corporation, is one of the

most well-known IMSI catchers, but there are various other models on the market.

399. Brief for Electronic Frontier Foundation, et al. as Amici Curiae Support-

ing Defendant-Appellant at 19, United States v. Patrick, No. 15-2443 (7th Cir. Jan.

22, 2016).

400. See, e.g., 844 F. Supp. 2d 982, 987 (D. Ariz. 2013).

401. See, e.g., United States v. Patrick, No. 13-CR-234, 2015 WL 106158, at

*2–*3 (data from carrier used to identify general location of a telephone, with an

IMSI catcher, then employed to pinpoint the precise location of the telephone

within an apartment), argued, No. 15-02443 (7th Cir. May 24, 2016).

402. See, e.g., What Is Geolocation of an IP Address?,

IP L

OCATION

INDER

www.iplocation.net.

403. See, e.g., Privacy & Credit Card Records: What Does Your Online & Credit

History Reveal?,

YBER

REND

(Apr. 8, 2015), http://www.cybertrend.com/article/

17089/privacy-and-credit-card-records.

404. See, e.g., ISACA,

EOLOCATION

ISK

, I

SSUES AND

TRATEGIES

5, 8

(2011),

http://www.isaca.org/groups/professional-english/wireless/groupdocuments/ge-

olocation_wp.pdf; Andrew E. Taslitz, The Fourth Amendment in the Twenty-First Cen-

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 621

technologies involved in storing, analyzing, and combining the data

with other sources is steadily “growing exponentially more power-

ful.”

405

Even kinetic photos taken by a smart phone include loca-

tion data and time and date stamps (when these functions are not

disabled). Images can be read using facial recognition technology,

placing particular individuals in particular places at particular

times.

When cameras are mounted on unmanned aerial systems

(UAS), mobile monitoring may be enabled.

406

Drones open new

ways to conduct surveillance.

407

They can fly virtually undetected at

higher altitudes, remain stationary outside buildings at lower alti-

tudes, and follow individuals in real time.

408

They can be program-

med to track GPS chips and can be fitted with video and audio

surveillance equipment, with the information continuously re-

corded either on the device or at a remote location.

409

Drones can

incorporate technologies ranging from remote biometric identifica-

tion and heat sensors, to radar, infrared cameras, and “sniffers,”

enabling them to detect particles suspended in the air.

410

Although

tury: Technology, Privacy, and Human Emotions, 65

& C

ONTEMP

. P

ROBLEMS

125,

127 (2002) (discussing Tampa, Florida law enforcement pairing of CCTV and fa-

cial recognition technology to find criminals in crowds).

405. David Alan Sklansky, Too Much Information: How Not to Think About Privacy

and the Fourth Amendment, 102

. L. R

1069, 1085–86 (2014).

406. Andrew Conte, Drones with Facial Recognition Technology Will End Anonym-

ity, Everywhere,

USINESS

NSIDER

(May 27, 2013), http://www.businessinsider.com/

facial-recognition-technology-and-drones-2013-5.

407. Over the past five years, there has been an upsurge in the number of law

review notes, comments, and articles looking at the impact of drones on Fourth

Amendment doctrine. See, e.g., M. Ryan Calo, The Drone as Privacy Catalyst, 64

TAN

L. R

. O

NLINE

29, 32 (2011); Matthew R. Koerner, Note, Drones and the Fourth

Amendment: Redefining Expectations of Privacy, 64

UKE

L. J.

1129 (2015); Timothy T.

Takehashi, Drones and Privacy, 14

OLUM

. S

. & T

ECH

. L. R

72, 72 (2013); An-

drew B. Talai, Comment, Drones and Jones: The Fourth Amendment and Police Discre-

tion in the Digital Age, 102

. L. R

729, 731–32 (2014); John Villasenor,

Observations from Above: Unmanned Aircraft Systems and Privacy, 36

ARV

. J. L. & P

’

457, 459 (2013); Philip J. Hiltner, Comment, The Drones Are Coming: Use of

Unmanned Aerial Vehicles for Police Surveillance and Its Fourth Amendment Implications, 3

AKE

OREST

J. L. & P

’

397, 397 (2013).

408. See also Koerner, supra note 407, at 1133, 1150–53 (noting the unique

qualities of drones and the range of technologies that they carry).

409. See also

NUJ

URI

, A S

URVEY OF

NMANNED

ERIAL

EHICLES

(UAV)

FOR

RAFFIC

URVEILLANCE

1, 2 (2005) (unpublished manuscript), http://

www.ugpti.org/smartse/research/citations/downloads/Puri-A_Survey_of_Un

manned_Aerial_Vehicles_for_Traffic_Surveillance-2005.pdf.

410. Andrew Conte, supra note 406; Surveillance Drones,

LECTRONIC

RONTIER

OUNDATION

, https://www.eff.org/issues/surveillance-drones. See also Surveillance

and Monitoring with UAVs,

ICRODRONES

COM

, https://www.microdrones.com/en/

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622 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

the battery time for most commercial drones is limited (up to 90

minutes in the air),

411

custom builds can be designed to stay aloft

longer, with replacements sequenced to provide for continuous sur-

veillance.

412

Not only are drones more maneuverable and in many

ways more technologically sophisticated than helicopters, but they

also require fewer resources to operate. While a police helicopter

may cost upwards of one million dollars just for the aircraft (not to

mention fuel, pilots, and other equipment), drones run in the tens

to hundreds of dollars.

413

Together, these and other technologies enable industry and

government to collect massive amounts of information about indi-

viduals as they move through public space.

414

Four points here de-

serve notice.

First, it appears that law enforcement is making increasing use

of locational information. For example, according to RAND, by

2014, 71% of state police departments were using license plate

readers, while 85% of police departments stated that they planned

to obtain or to expand their use of the technology.

415

Vermont’s

statewide ALPR system yielded nearly nine million records between

July 2013 and December 2014.

416

The Northern California Re-

gional Intelligence Center, which covers the area from Monterey

County up to Humboldt County, collected more than forty-six mil-

applications/areas-of-application/monitoring/ (noting use of “a thermal camera

payload so that living beings . . . can be more easily detected in darkness or in

dense vegetation,” and listing the range of surveillance activities that the drone can

undertake).

411. See Korey Smith, General Drone Specs and Price Chart,

IRST

RONE

COM

(Oct. 1, 2016), http://myfirstdrone.com/tutorials/buying-guides/best-drones-for-

sale/; Microdrones MD4-1000: Robus and Powerful UAV/Drone Model,

ICRODRONES

https://www.microdrones.com/en/products/md4-1000/at-a-glance/ (last visited

Oct. 17, 2016).

412. Military drones can stay aloft for hours or days at a time, with coverage of

entire cities, as well as the ability to read a milk carton from 60,000 feet in the air.

Surveillance Drones,

LECTRONIC

RONTIER

OUNDATION

, https://www.eff.org/issues

/surveillance-drones (last visited Oct. 17, 2016).

413. Koerner, supra note 407, at 1148–49.

414. Transit passes, access cards, and automated toll booth systems provide

just a few of many more examples of location tracking.

415. Keith Gierlack, et al., License Plate Readers for Law Enforcement: Opportuni-

ties and Obstacles,

RAND C

ORPORATION

(2014), at 8, http://www.rand.org/pubs/

research_reports/RR467.html.

416.

VT D

’

. S

AFETY

NNUAL

EPORT TO THE

ERMONT

ENATE AND

OUSE

OMMITTEES ON

UDICIARY AND

RANSPORTATION AS

EQUIRED BY

23 V.S.A.

§1607

UTOMATED

ICENSE

LATE

ECOGNITION

YSTEMS

(2015), http://mediad

.publicbroadcasting.net/p/vpr/files/201503/VT-2014-ALPR-Annual-Report-

VPR.pdf.

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 623

lion images between May 2014 and April 2015.

417

The impact of

even a single officer using a license reader is significant: one police-

man in Maryland was able to scan more than 48,000 vehicles over a

27-day period, in the process issuing 255 traffic citations and find-

ing 26 drivers with suspended licenses, 16 vehicle-emission viola-

tions, 4 stolen cars, and 1 expired license plate.

418

Private industry has moved into the ALPR field. Digital Recog-

nition Network, for instance, claims to scan 40% of all U.S. vehicles

each year.

419

They operate in conjunction with approximately 400

car repossession companies across the country, scanning up to 1800

plates per minute.

420

The involvement of private industry has, in

turn, generated more government use of the technology. Vigilant

states that its ALPR database includes more than 2.8 billion plate

scans, which it expands by more than seventy million scans per

month.

421

It provides the system for free to Texas law enforce-

ment.

422

In return, the government gives Vigilant access to out-

standing court fees, which the company links to the license plates of

those owing the fees.

423

It then alerts law enforcement when the

cars are found, giving officers the opportunity to pull over the cars

to obtain the fees, along with a 25% processing fee, which is then

given directly back to Vigilant.

424

Vigilant’s privacy policy notes,

“The images stored in the system are collected from areas visible to

417. Samantha Weigel, Who’s Watching Who?: License Plate Readers Used Through-

out San Mateo County,

AILY

OURNAL

(Apr. 8, 2015), http://www.sm

dailyjournal.com/articles/lnews/2015-04-08/whos-watching-who-license-plate-

readers-used-throughout-san-mateo-county/1776425141346.html; see also NCRIC

ALPR FAQs,

ORTHERN

ALIFORNIA

EGIONAL

NTELLIGENCE

ENTER

(Feb. 2015),

https://ncric.org/html/ALPR-FAQ-Feb-2015.pdf.

418. Jeremy Hsu, 70 Percent of U.S. Police Departments Use License Plate Readers,

IEEE S

PECTRUM

(Jul. 8, 2014), http://spectrum.ieee.org/cars-that-think/transpor

tation/sensors/privacy-concerns-grow-as-us-police-departments-turn-to-license-

plate-readers; Weigel, supra note 417 (noting that one patrol car, with four

mounted ALPRs, can obtain some 10,000 images during a 12-hour shift).

419. Seth Wenig, Private License Plate Scanners Amassing Vast Databases Open to

Highest Bidders, RT (Mar. 6, 2014), https://www.rt.com/usa/license-scanners-pri

vate-database-046/.

420. Id.

421. Dave Maass, “No Cost” License Plate Readers Are Turning Texas Police into

Mobile Debt Collectors and Data Miners,

LECTRONIC

RONTIER

OUNDATION

(Jan. 26,

2016), https://www.eff.org/deeplinks/2016/01/no-cost-license-plate-readers-are-

turning-texas-police-mobile-debt-collectors-and; see also, Vigilant Products,

IGILANT

OLUTIONS

, https://vigilantsolutions.com/products (last visited Oct. 17, 2016).

422. Maass, supra note 421.

423. Id.

424. Id.

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624 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

the public where there is no reasonable expectation of privacy.”

425

The company further claims a First Amendment right to collect and

disseminate the information.

426

Vigilant retains the right to sell the

data to anyone for commercial purposes, as well as for market re-

search purposes.

427

And it retains the information “as long as it has

commercial value.”

428

Like companies, individuals also can make use of the technol-

ogy. Whether in public, commercial, or private hands, the price of

the scanners is steadily falling,

429

even as they are subject to few, if

any, legal limits.

As for cell site simulators, the ACLU, has documented sixty-six

agencies in two dozen states, as well as Washington, D.C., that own

and use them.

430

At the federal level, the FBI; DEA; U.S. Secret Ser-

vice; Immigration and Customs Enforcement; U.S. Marshals Ser-

vice; Bureau of Alcohol, Tobacco, Firearms, and Explosives;

Internal Revenue Service; U.S. Army; U.S. Navy; U.S. Marine Corps;

U.S. National Guard; U.S. Special Operations Command; and Na-

tional Security Agency all own IMSI catchers.

431

Network data collected by companies similarly appears to be a

growing source of government data. Seven years ago, a Sprint/

Nextel executive claimed that over the previous thirteen months,

the company had received some eight million requests from law

enforcement for location data.

432

In 2012, a Congressional inquiry

found that cell phone carriers had provided subscriber information

relating to texts, locational data, and calling records, to law enforce-

ment some 1.3 million times.

433

425. LPR Usage and Privacy Policy,

IGILANT

OLUTIONS

https://vigilantsolu-

tions.com/lpr-usage-privacy-policy (last visited Oct. 17, 2016).

426. Id.

427. Id.

428. Id.

429. Julia Angwin & Jennifer Valentino-Devries, New Tracking Frontier: Your Li-

cense Plates,

ALL

. J.

(Sept. 29. 2012), http://online.wsj.com/article/

SB10000872396390443995604578004723603576296.html.

430. Stingray Tracking Devices: Who’s Got Them?,

ACLU

, https://www.aclu.org/

map/stingray-tracking-devices-whos-got-them (last visited Oct. 17, 2016).

431. Id.

432. Herbert, supra note 274, at 462 (citing Kevin Bankston, Surveillance

Shocker: Sprint Received 8 Million Law Enforcement Requests for GPS Location Data in the

Past Year,

LECTRONIC

RONTIER

OUNDATION

(Dec. 1, 2009, 1:45 PM), http://

www.eff.org/deeplinks/2009/12/surveillance-shocker-spring-received-8-million-

law).

433. David Kravets, 1.3M Cellphone Snooping Requests Yearly? It’s Time for Privacy

and Transparency Laws,

IRED

(Jul. 11, 2012), https://www.wired.com/2012/07/

mobile-data-transparency/.

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 625

As for drones, in 2014, when a rancher refused to turn over six

cows that had wandered onto his property, North Dakota law en-

forcement enlisted the aid of a DHS Predator drone to locate and

arrest him.

434

Although the state prosecutor stated that it was the

first time unmanned surveillance aircraft had been used by North

Dakota, between 2010 and 2012 Customs and Border Patrol had

already flown nearly 700 surveillance missions for federal, state, and

local law enforcement agencies.

435

Quite apart from the federal arsenal, Grand Forks County,

North Dakota operates its own drones.

436

In 2011, the Sheriff’s De-

partment began training a Small Unmanned Aircraft Unit in collab-

oration with the University of North Dakota’s John D. Odegard

School of Aerospace Sciences.

437

In March 2013, the FAA explicitly

authorized the Sheriff’s Department to use drones for law enforce-

ment purposes.

438

The first use of a drone during a police mission

was in May 2013.

439

Two years later, North Dakota became the first

434. Joe Wolverton, II, First Man Arrested by Aid of Drone Convicted in North Da-

kota,

MERICAN

(Feb. 1, 2014), http://www.thenewamerican.com/usnews/

constitution/item/17534-first-man-arrested-by-aid-of-drone-convicted-in-north-da-

kota. See also Jason Koebler, North Dakota Man Sentenced to Jail in Controversial Drone-

Arrest Case,

U.S. N

EWS

& W

ORLD

EPORT

(Jan. 15, 2014), http://www.usnews.com/

news/articles/2014/01/15/north-dakota-man-sentenced-to-jail-in-controversial-

drone-arrest-case; Michael Peck, Predator Drone Sends North Dakota Man to Jail,

ORBES

(Jan. 27, 2014), http://www.forbes.com/sites/michaelpeck/2014/01/27/

predator-drone-sends-north-dakota-man-to-jail/#37c69afd5853.

435. Peck, supra note 434; see also Jennifer Lynch, Customs & Border Protection

Loaned Predator Drones to Other Agencies 700 Times in Three Years According to “Newly

Discovered” Records,

LECTRONIC

RONTIER

OUNDATION

(Jan. 4, 2014), https://

www.eff.org/deeplinks/2014/01/newly-discovered-drone-records-show-customs-

border-protection-flew-its-predator.

436. Kelsey D. Atherton, Inside One of the FAA’s New Drone Test Sites,

OPULAR

CIENCE

(Jan. 2, 2014), http://www.popsci.com/article/technology/inside-one-

faas-new-drone-test-sites. In November 2012, the FAA issued Grand Forks county

(North Dakota) Sheriff’s Department a Certificate of Authorization, permitting

the operation of a Draganflyer X6 small unmanned aircraft system (sUAS) in 16

counties in northeastern North Dakota. Press Release, Grand Forks County Sher-

iff’s Department, Small Unmanned Aircraft System (Dec. 6, 2012), http://www.

draganfly.com/pdf/Grand%20Forks%20County%20-%20Press%20Release.pdf

(explaining that the drone has six rotors, weighs less than three pounds, and

streams real-time video to ground station and takes high-definition digital still

images).

437. See Press Release, supra note 436.

438. See Atherton, supra note 436.

439. Id.

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626 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

state to legalize the use of armed drones, pairing surveillance con-

cerns with non-lethal force.

440

The number of police departments using drones continues to

expand.

441

By 2015, some two dozen had been fully equipped in

their use, with sixty more requesting FAA certification.

442

Only

fourteen states require a warrant prior to law enforcement using

drones for surveillance.

443

The second observation to be made is that the insight provided

by such data into individuals’ private lives is profound. Locational

tracking shows where you go, what you do, and who you are with

when you do so.

444

It can reveal an individual’s identity,

445

race,

446

440. H.R. 1328, 64th Leg. (N.D. 2015) at § 5(1) (only prohibiting the use of

unmanned aerial vehicles “armed with any lethal weapons”); see also Henry Austin,

North Dakota Becomes First U.S. State to Legalize Use of Armed Drones by Police,

NDEPEN-

DENT

(Sept. 8, 2015), http://www.independent.co.uk/news/world/americas/

north-dakota-becomes-first-us-state-to-legalise-use-of-armed-drones-by-police-1049

2397.html; Justin Glawe, First State Legalizes Taser Drones for Cops, Thanks to a Lobbyist,

AILY

EAST

(Aug. 26, 2016), http://www.thedailybeast.com/articles/2015/

08/26/first-state-legalizes-armed-drones-for-cops-thanks-to-a-lobbyist.html.

441. Not only do police departments operate their own devices, but private

drone footage has also been used in arrests. See, e.g., Jordan Pearson, Meet the ‘Drone

Vigilante’ Who Spies on Sex Workers,

OTHERBOARD

(Apr. 4, 2016), http://mother

board.vice.com/read/drone-vigilante-brian-bates-johntv-oklahoma-spies-on-sex-

workers?trk_source=popular.

442. Veronique Dupont, Drone Policing in U.S. Seen as “Wild West,”

AHOO

EWS

(Sept. 12, 2015), https://www.yahoo.com/news/drone-policing-us-seen-wild-

west-215907770.html; Anthea Mitchell, Should America Be Worried About Police

Drones?,

HEAT

HEET

(May 15, 2015), http://www.cheatsheet.com/politics/

are-police-drones-a-privacy-nightmare-or-a-safety-advantage.html/?a=viewall;

see

also 2011-2012 FAA List of Drone License Applicants, obtained via FOIA request,

available at https://www.eff.org/document/2012-faa-list-drone-applicants.

443. Kaveh Waddell, Few Privacy Limitations Exist on How Police Use Drones,

TLANTIC

(Feb. 5, 2015), http://www.theatlantic.com/politics/archive/2015/02/

few-privacy-limitations-exist-on-how-police-use-drones/458583/.

444. See generally Andrew J. Blumberg & Peter Eckersley, On Locational Privacy,

and How to Avoid Losing it Forever,

LECTRONIC

RONTIER

OUNDATION

, 1–2 (Aug.

2009), https://www.eff.org/files/eff-locational-privacy.pdf (discussing how systems

have “strip[ped] away” locational privacy by allowing other people to find out per-

sonal information by “consulting location databases”).

445. A. Cecaj, M. Mamei & N. Bicocchi, The Third IEEE International Work-

shop on the Impact of Human Mobility in Pervasive Systems and Applications, Re-

Identification of Anonymized CDR Datasets Using Social Network Data,

237–42

(2014); S.

Ji, W. Li, M. Srivatsa, J. S. He, & R. Beyah, Structure Based Data De-Anonymization of

Social Networks and Mobility Traces,

NFORMATION

ECURITY

237, 237–54 (2014); A.

Cecaj, M. Mamei & F. Zambonelli, Re-Identification and Information Fusion Between

Anonymized CDR and Social Network Data,

J. A

MBIENT

NTELLIGENCE

& H

UMANIZED

OMPUTING

83, 83 (Jul. 14, 2015); Yves-Alexandre de Montjoye, et al., Unique in the

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 627

gender,

447

age,

448

marital status,

449

religious beliefs, medical condi-

tions, occupation,

450

and intimate relationships.

451

It records hob-

bies and predilections. And it can be used to predict where an

individual is likely to be and what an individual is likely to do—and

with whom—in the future.

452

In 2011, the Information Systems Au-

dit and Control Association (ISACA), a non-profit, multi-national

trade organization, noted “a growing consensus that geolocation

data should be classified as sensitive.”

453

The organization evinced

concern that “current law does not articulate a stance on the pri-

vacy and security aspect of geolocation.”

454

More recently, a team of

researchers from Louvain University in Belgium, and Harvard and

MIT in the United States, warned that “Given the amount of infor-

mation that can be inferred from mobility data, as well as the poten-

tially large number of . . . mobility datasets available,” significant

implications for privacy are on the line.

455

Crowd: The Privacy Bounds of Human Mobility,

ATURE

(Mar. 25, 2013), http://

www.nature.com/articles/srep01376.

446. Christopher J. Riederer, Sebastian Zimmeck, Coralie Phanord, Augustin

Chaintreau & Steven M. Bellovin, “I Don’t Have a Photograph, But You Can Have My

Footprints.”—Revealing the Demographics of Location Data,

COSN’ 15: P

ROC

. 2015

ACM C

ONF

NLINE

. N

ETWORKS

185, 192 (Nov. 2, 2015).

447. N. J. Yuan, W. Zhong, F. Zhang, & X. Xie, You Are Where You Go: Inferring

Demographic Attributes from Local Check-ins,

WSDM ‘15: P

ROC

. 8

NNUAL

ACM

’

ONF

EARCH AND

ATA

INING

295, 297 (2015); Sanja Brdar,

Dubravko Culibrk & Vladimir Crnojevic Demographic Attributes Prediction on the Real-

World Mobile Data,

OBILE

ATA

HALLENGE

ORKSHOP

(2012), https://re-

search.nokia.com/files/public/mdc-final202-brdar.pdf, cited in Steven M. Bellovin,

Renee M. Hutchins, Tony Jebara & Sebastian Zimmeck, When Enough Is Enough:

Location Tracking, Mosaic Theory, and Machine Learning, 8

N.Y.U. J. L. & L

IBERTY

556,

559 & n.8 (2013–2014).

448. See Brdar et al., supra note 447.

449. See Yuan et. al, supra note 447, at 297; see also Brdar et al., supra note 447.

450. See Brdar et al., supra note 447.

451. See generally E. Cho, S. A. Myers & J. Leskovec, Friendship and Mobility: User

Movement in Location-Based Social Networks,

KDD ‘11: P

ROC

. 17

ACM SIGKDD

’

ONF

NOWLEDGE

ISCOVERY

& D

ATA

INING

1082 (2011) (using cell

phone data as evidence to advance understanding of the “basic laws governing

human movement and dynamics.”); David J. Crandall, et al., Inferring Social Ties

from Geographic Coincidences, 107

ROC

. O

F THE

’

CAD

22436 (2010).

452. See Riederer, et al., supra note 446, at 192; Bellovin, et al., supra note 447,

at 558 n.9.

453. ISACA,

EOLOCATION

: R

ISK

, I

SSUES AND

TRATEGIES

5, 9

(2011), http://

www.isaca.org/groups/professional-english/wireless/groupdocuments/

geolocation_wp.pdf.

454. Id.

455. See Montjoye, et al., supra note 445, at 4.

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628 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

Third, the fact that industry itself is collecting this data has im-

plications for government access to the information. As a matter of

law, the Supreme Court in Kyllo cited the ubiquitous nature of tech-

nology as a consideration in whether individuals held a privacy in-

terest in it. Underlying the legal argument is the same approach

that marks the private/public distinction: if private corporations

have access to the information, then why should the government be

forced to close its eyes or cover its ears? And legal doctrine goes

further: since the 1970s, the decision by consumers to entrust this

data to third parties means that individuals no longer hold a privacy

right in the information (see discussion, infra Part IV).

456

Fourth, to the extent that the Fourth Amendment analysis

hinges on an initial determination at the moment of collection, it

does not provide for a later interest to arise as the volume of infor-

mation expands. The basic argument, which Foreign Intelligence

Surveillance Court (FISC) Judge Claire Eagan expressed with re-

gard to the NSA collection of telephony metadata under Section

215 of the USA PATRIOT Act, is that zero plus zero still equals

zero.

457

If there is no privacy interest at the front end, then increas-

ing the amount of time, or the volume of information, does not

bring a privacy interest into being ex nihilo.

458

The problem with applying this approach to the collection of

locational data is that the private/public distinction on which it is

based fails to acknowledge the additional privacy interests entailed

in repeated observation. The value of aggregated information

changes when there is more of it.

459

As the lower courts have confronted the questions raised by

these new technologies, a number have eschewed privacy considera-

tions. In 2012, for instance, the Sixth Circuit considered law en-

forcement’s use of subscriber information, cell site information,

456. See Paul Ohm, The Fourth Amendment in a World Without Privacy, 81

ISS

L. J.

1309, 1331 (2012) (exploring the relationship between public and private

surveillance).

457. In re Application of the Federal Bureau of Investigation for an Order

Requiring the Production of Tangible Things from [Redacted Text], BR 13-109, at

9 (FISA Ct. Aug. 29, 2013), https://www.aclu.org/files/assets/br13-09-primary-or-

der.pdf; see also Donohue, Bulk Metadata, supra note 6, at 867 (discussing Judge

Eagan’s approach);

ONOHUE

, F

UTURE

, supra note 6

at 120–21

458. See Donohue, Bulk Metadata, supra note 6, at 867 (discussing Judge

Eagan’s approach).

459. Bellovin et al., supra note 447, at 558–59. This approach also ignores the

important role of limited resources in protecting privacy. Law enforcement only

has access to a certain amount of police time. Thus, the placement of a tail on a

suspect has to rise to a level of importance that would justify using the resources.

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 629

GPS real-time location, and “ping” data to find the location of a

drug dealer.

460

The Court considered Knotts as controlling.

461

Judge Rogers began United States v. Skinner by stating, “When

criminals use modern technological devices to carry out criminal

acts and to reduce the possibility of detection, they can hardly com-

plain when the police take advantage of the inherent characteristics

of those very devices to catch them.”

462

The drug runners had used

“pay as you go (and thus presumably more difficult to trace) cell

phones to communicate.”

463

For the court, Skinner had no “reason-

able expectation of privacy in the data given off” by his phone.

464

Collecting the data was akin to “trailing a defendant.”

465

That it was

more efficient, or effective, did not make it unconstitutional.

466

few other courts have come to a similar conclusion for historic cell

site data.

467

Not all courts agree. Some state courts have come out on the

other side of the question, finding constitutional protections. The

Massachusetts Supreme Judicial Court considers mobile phone lo-

cation data to be even more concerning than the use of GPS for

cars, because of the greater privacy interests at stake.

468

The New

Jersey Supreme Court similarly has held that cell phone location

data, in particular, blurs the distinction between public and private

space.

469

The Florida Supreme Court similarly considers the use of

cell site location information to constitute a search within the

meaning of the Fourth Amendment—thus triggering the need for

a prior warrant.

470

The court warned, “the ease with which the gov-

ernment, armed with current and ever-expanding technology, can

now monitor and track our cellphones, and thus ourselves, with

minimal expenditure of funds and manpower, is just the type of

‘gradual and silent encroachment[ ]’ into the very details of our

460. United States v. Skinner, 690 F.3d 772, 774 (2012).

461. Id. at 777.

462. Id. at 774.

463. Id.

464. Id. at 777.

465. Id. at 778.

466. See United States v. Forest, 355 F.3d 942, 951 (6th Cir. 2004) (pinging a

cell phone to make up for having lost visual contact with a suspect considered

outside Fourth Amendment protections because “the DEA agents could have ob-

tained the same information by following the car”).

467. See, e.g., United States v. Davis, 785 F.3d 498, 518 (11th Cir. 2015) (en

banc), cert. denied, 135 S. Ct. 479 (2015) (mem.); In re Application for Cell Site

Data, 724 F. 3d 600, 600 (5th Cir. 2013).

468. Commonwealth v. Augustine, 4 N.E. 3d 846, 861–62 (Mass. 2014).

469. State v. Earls, 70 A.3d 630, 642 (N.J. 2013).

470. Tracey v. State, 152 So. 3d 504, 526 (Fla. 2014).

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630 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

lives that we as a society must be vigilant to prevent.”

471

Other

courts have taken a similar approach for historic cell site data

472

well as live tracking.

473

In sum, despite Katz’s recognition that the Fourth Amendment

protects people, not places, the doctrine has doggedly held on to

the property assumptions that marked Olmstead. The Supreme

Court continues to rely on the curtilage of the home, and the oper-

ation of the senses as the litmus test for whether new technologies

trigger Fourth Amendment interests at the outset—placing further

privacy claims beyond constitutional reach. The Court’s logic is that

when an individual leaves the protections of the home, anything

one says or does can be seen and heard by others. Law enforcement

officers, in turn, should not be forced to close their eyes or to cover

their ears. They have a right to be in public, and to observe what

others witness.

That may be true as far as walking down the street on a particu-

lar occasion. But for all such movements to be observed, recorded,

and analyzed, another individual would have to follow us around

twenty-four hours a day, for days, even months or years on end.

There are two problems with this claim.

First, what one person could observe at a particular moment

can be considered qualitatively different from what one person

could observe at all times. There is a distinction to be drawn here

between single observation and multiple incident observations.

When driving down the street, for instance, it is not just unlikely,

but virtually impossible for a bystander to track all of our move-

ments in a car.

474

Another person also could be in a car, tailing us,

but as most people who have had to follow a friend just to get to

one destination could attest, even on a limited basis, when both

drivers know that that is the pre-arranged plan and are trying to do it,

471. Id. at 522 (quoting James Madison, Speech in the Virginia Ratifying Con-

vention on Control of the Military (June 16, 1788)); see also Brief for Electronic

Frontier Foundation, et al. as Amici Curiae Supporting Defendant-Appellant at

19–20, United States v. Patrick, No. 15-2443 (7th Cir. Jan. 22, 2016).

472. See, e.g., United States v. Graham, 796 F.3d 332, 344–45 (4th Cir. 2015),

reh’g en banc granted, 624 F. App’x 75 (4th Cir. 2015); In re Application for Tel. Info.

Needed for a Criminal Investigation, 2015 WL 4594558 at *12 (N.D. Cal. 2015),

appeal dismissed, No. 15-16760 (9th Cir. 2016).

473. See, e.g., United States v. White, 62 F. Supp. 3d 614, 622–23 (E.D. Mich.

2014); United States v. Powell, 943 F. Supp. 2d 759, 793 (E.D. Mich. 2013).

474. See Stephen E. Henderson, Nothing New Under the Sun? A Technologically

Rational Doctrine of Fourth Amendment Search, 56

ERCER

L. R

507, 548 (2005)

(“[M]ost drivers would not think they were conveying their entire driving route to

bystanders.”).

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 631

tailing can be difficult to put into execution. Lights change. The

second car may miss the light. If the first car does not pull over to

wait, it can be difficult for the second car to catch them. One car

may need to stop at a train junction, or when a school bus stops to

let off children. An emergency vehicle may block the road, or a

pedestrian may enter a crosswalk. Other cars may cut between the

two vehicles, making it difficult to see the lead car. This may cause

the second car to miss a turn. One car may have car trouble and

have to pull over. Myriad hindrances may arise—even while follow-

ing one car, for a limited time, to get to one destination. Multiply

these factors for every destination over an indefinite period, and

the sheer unlikelihood of successfully observing every moment be-

comes clear. No bystander could collect this kind of information.

Second, no one reasonably expects that another person would

engage in such behavior. To the contrary, if someone did attempt

to monitor one’s every move, many people would regard it as not

just unacceptable but downright creepy. This is why we have tempo-

rary restraining orders.

475

They are used to prevent others from in-

vading our private lives—even if their actions are limited to

tracking our every move in the public domain.

2. Recording and Analysis: Informants and the First Amendment

New technologies allow not just for public tracking, but also

for the recording and analysis of the data. These are two separate

steps. Yet neither operation triggers protections under the Fourth

Amendment—even though the act of recording allows for more in-

formation to be obtained, which, when analyzed, yields yet deeper

insight into an individual’s life.

a. Recording of Data

In United States v. Caceres, another case from the 1970s, the Su-

preme Court considered whether the secret recording of a private

conversation by someone privy to the communication qualified as a

search within the meaning of the Fourth Amendment.

476

It con-

475. 18 U.S.C. § 2261A (2006) (to obtain a temporary restraining order

under federal law, an individual must, inter alia, demonstrate the other person’s

intent to “harass, or place under surveillance with intent to kill, injure, harass, or

intimidate another person”); Domestic Violence Civil Protection Orders (CPOs),

Bar

’

OMM

’

N ON

OMESTIC

& S

EXUAL

IOLENCE

(Mar. 2014) (listing all state TRO

laws, also known as civil protection orders, civil harassment restraining orders, or

stalking protective orders), http://www.americanbar.org/content/dam/aba/ad

ministrative/domestic_violence1/Resources/statutorysummarycharts/2014%20

CPO%20Availability%20Chart.authcheckdam.pdf.

476. 440 U.S. 741 (1979).

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632 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

cluded that it did not: “Neither the Constitution nor any Act of

Congress requires that official approval be secured before conversa-

tions are overheard or recorded by Government agents with the

consent of one of the conversants.”

477

The information merely re-

produced what the agent could have written down, so no further

privacy interest was implicated.

In its ruling, the Court relied on a series of cases, in which the

Court had considered whether the recording of the information

altered the quality of the privacy intrusion and concluded that it

had not.

The first case in the series was the 1952 case of On Lee v. United

States, in which an undercover agent, wired with a microphone, was

sent into the suspect’s laundromat to obtain incriminating evi-

dence.

478

An agent from the Bureau of Narcotics, who listened to

the conversations inside the laundromat from a remote location,

later testified at trial.

479

Writing on behalf of the Court, Justice Jack-

son suggested that by allowing the agent onto his premises, and

divulging incriminating information, On Lee had consented to law

enforcement access to the information.

480

Just over a decade later, the Court considered a similar fact

pattern in Lopez v. United States.

481

This time, an agent from the

Internal Revenue Service wore a recording device.

482

The Court re-

jected the argument that the defendant had a “constitutional right

to rely on possible flaws in the agent’s memory, or to challenge the

agent’s credibility without being beset by corroborating evidence

that is not susceptible of impeachment.”

483

To the contrary, “the

risk that petitioner took in offering a bribe . . . fairly included the

risk that the offer would be accurately reproduced in court,

whether by faultless memory or mechanical recording.”

484

The de-

vice had not intercepted new information.

485

It had just allowed for

the information that was conveyed to the informer to be relayed

more accurately in court.

The pattern continued. In Hoffa v. United States, the Supreme

Court determined that a government informant relaying conversa-

477. Id. at 744.

478. 343 U.S. 967, 969 (1952).

479. Id. at 970.

480. Id. at 971.

481. 373 U.S. 427 (1963).

482. Id. at 430.

483. Id. at 439.

484. Id.

485. Id.

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tions to federal law enforcement agents did not violate the Fourth

Amendment, on the grounds that Jimmy Hoffa invited the inform-

ant into the room.

486

In Lewis v. United States, the Court again ruled

the evidence admissible on the grounds that the defendant had in-

vited the undercover agent into his home on numerous occa-

sions.

487

These cases emphasized the voluntariness of the person

confiding information in another person.

The informant cases also came down on the side of encourag-

ing, rather than discouraging, the collection of more accurate infor-

mation. That it was done with the aid of technology, and not via

ordinary recall using human capacities, mattered little. In the

Court’s view, it was not different information that was being ob-

tained, but simply information that more closely reflected what ac-

tually occurred. If it could be heard in the first place, then whether

or not the brain had the ability to recall such detailed information

was of little or no consequence.

Katz did little to alter the Court’s view of the recording of in-

formation. Justice White cited the informant cases in his concur-

rence, stating (in dicta) that they had been “undisturbed” by the

Court’s ruling.

488

Subsequent cases substantiated Justice White’s claim. In 1971,

in United States v. White, law enforcement officers recorded conver-

sations between an informer and a suspect.

489

When the informer

could not be located for the trial, the prosecution substituted the

electronic recording.

490

The Court found no Fourth Amendment

issue: “[A] police agent who conceals his police connections may

write down for official use his conversations with a defendant and

testify concerning them, without a warrant authorizing his en-

counters with the defendant and without otherwise violating the lat-

ter’s Fourth Amendment rights.”

491

For the Supreme Court, there was no difference among an in-

former (a) writing down his recollections of the conversation, (b)

recording the conversation with equipment secreted on his person,

or (c) carrying equipment that transmitted the conversation to law

enforcement officers or to recording devices.

492

The Court ex-

486. 385 U.S. 293, 302 (1966).

487. Lewis v. United States, 385 U.S. 206, 212 (1966).

488. Katz v. United States, 389 U.S. 347, 363 n.** (1967) (White, J.,

concurring).

489. 401 U.S. 745, 746–47 (1971) (plurality opinion).

490. Id.

491. Id. at 751 (citing Hoffa v. United States, 385 U.S. 293, 300–03 (1966)).

492. Id.

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634 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

plained, “If the conduct and revelations of an agent operating with-

out electronic equipment do not invade the defendant’s

constitutionally justifiable expectations of privacy, neither does a si-

multaneous recording of the same conversations made by the agent

or by others from transmissions.”

493

In undertaking criminal enter-

prises, one of the risks is that those with whom one deals are un-

trustworthy. While the informer’s unavailability at trial might raise

evidentiary problems or introduce potential questions of

prosecutorial misconduct, it was immaterial as to whether the re-

cording itself invaded the target’s Fourth Amendment rights.

494

There was no appreciable difference between someone witnessing

something happen and later recording it, and documenting what

was said real-time, by, or with the consent of, individuals privy to the

conversation.

Translated into private/public space doctrine, the potential for

the government to record activity would fall outside the confines of

the Fourth Amendment. What a police officer—or, indeed, any citi-

zen—could witness in public would incur no further intrusion into

an individual’s privacy if the officer—or citizen—recorded it as it

was happening.

In 1972, the Court confronted a similar private/public scena-

rio and, in the context of the First Amendment, adopted a parallel

approach. It was an era of civil unrest. The Department of the Army

was called upon to assist local authorities in Detroit. Protesters

brought a class action suit in District Court, seeking relief for their

claim that the military’s surveillance of lawful political activity un-

dermined their First Amendment rights.

495

The data-gathering sys-

tem used by the military placed the Army in a law enforcement role.

Just as the Court in the Fourth Amendment cases looked to the

ability of ordinary citizens to access the same data as a metric for

the scope of government power, so, too, did the Appellate Court

and, later, the Supreme Court, look to ordinary police powers to

assess what access to information should be provided to the mili-

tary. The Court of Appeals explained, “To quell disturbances or to

prevent further disturbances, the Army needs the same tools and,

most importantly, the same information to which local police have

493. Id.

494. White, 401 U.S. at 754.

495. Laird v. Tatum, 408 U.S. 1 (1972).

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access.” Indeed, it may have even greater need than the local po-

lice, since they may be unfamiliar with the local population.

496

The Army discharged its mission by collecting information

about public meetings. It came from various sources:

[T]he principal sources of information were the news media

and publications in general circulation. Some of the informa-

tion came from Army Intelligence agents who attended meet-

ings that were open to the public and who wrote field reports

describing the meetings, giving such data as the name of the

sponsoring organization, the identity of speakers, the approxi-

mate number of persons in attendance, and an indication of

whether any disorder occurred.

497

Other information was derived from local police and other ci-

vilian law enforcement agencies.

498

The Supreme Court considered—and rejected—the proposi-

tion that recording public meetings had any First Amendment chil-

ling effect. To the contrary, the burden lay on those who attended

the meetings to demonstrate the danger of direct injury.

499

White dealt with taking notes from a recorded conversation.

500

The Supreme Court has not yet addressed video recordings or pho-

tographs. But two lower decisions have.

The first was the 1975 case of Philadelphia Yearly Meeting of Relig-

ious Society of Friends v. Tate.

501

The Philadelphia Police Department

had amassed files on about 18,000 people and organizations, in-

cluding information about their political views, personal associa-

tions, personal lives, and habits. In June 1970, officers publicly

announced the names of some of the individuals who had been

placed under surveillance. People involved brought suit, asserting

that the practice of collecting information on citizens lacked any

nexus to legitimate police purposes and deprived them of their

right to anonymity with regard to their political activities and as-

sociations. The plaintiffs argued that the collection chilled their

free exercise of speech and assembly and interfered with their abil-

496. Id. at 5 (“Since the Army is sent into territory almost invariably unfamil-

iar to most soldiers and their commanders, their need for information is likely to

be greater than that of the hometown policeman.”).

497. Id. at 6.

498. Id.

499. Id. at 14–15.

500. 401 U.S. 745, 746–47 (1971) (plurality opinion).

501. Phila. Yearly Meeting of Religious Soc’y of Friends v. Tate, 519 F.2d 1335,

1336–37 (1974).

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636 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

ity to form lawful political associations that represented unpopular

views.

502

The District Court disagreed. Consistent with Laird v. Tatum,

the fact that the police were engaged in an investigation did not

chill the citizens’ right to free speech.

503

The Court of Appeals re-

versed in part and affirmed in part, finding no additional Fourth

Amendment interest.

504

“[M]ere police photographing and data

gathering at public meetings” did not create any constitutional

questions—nor did sharing it with other agencies with law enforce-

ment interests.

505

Where the department went outside acceptable

bounds was by going on national television and informing the pub-

lic who they had under surveillance.

506

This decision reflected the private/public distinction, and it ac-

cepted that the recording of the information itself did not change

the quality of its collection as a matter of constitutional law. What is

odd about the case is that the distinction it drew—namely with

whom the information was shared—was determined after collection.

It sidestepped whether the recording of the data in the first place

qualified as a search within the meaning of the Fourth

Amendment.

In the 1970s, the Fourth Circuit considered the potential First

Amendment violation by law enforcement taking pictures at public

meetings and demonstrations.

507

It was common practice at the

time for police to photograph vigils, demonstrations, protests, and

political meetings, regardless of whether they were peaceful or

threatened violent behavior.

508

Judge Donald Russell, writing for

the Court, determined that there had not been any constitutional

intrusion.

509

He discounted any feeling of intimidation, citing to

Laird v. Tatum, to claim that simply knowing one was under surveil-

502. Id. at 1337.

503. Phila. Yearly Meeting of Religious Soc’y of Friends v. Tate, 382 F.Supp.

547, 549 (1974); 408 U.S. 14 (Burger, J.), (noting that a broad-scale investigation

was underway).

504. Tate, 519 F.2d at 1339.

505. Id. at 1337–38.

506. Id. at 1339 (“It cannot be doubted that disclosure on nationwide televi-

sion that certain named persons or organizations are subjects of police intelligence

files has a potential for a substantial adverse impact on such persons and organiza-

tions even though tangible evidence of the impact may be difficult, if not impossi-

ble, to obtain.”).

507. Donohoe v. Duling, 465 F.2d 196, 197 (4th Cir. 1972).

508. Id. at 197–98.

509. Id. at 199.

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lance was not sufficient to find a chilling effect.

510

The court was

skeptical that those attending the rally really did feel intimidated by

the presence of the cameras: “They did not object to being photo-

graphed; to the contrary, they solicited publicity both for their

meetings and for themselves by inviting representatives of the news

media, including photographers, to be present.”

511

By holding a

public meeting, in a public space, where ordinary citizens and news

outlets would see and hear what was being said, the targets of the

surveillance relinquished their right to prevent the government

from recording what whey said and did.

In his dissent, Judge Winter distinguished the case from Tatum,

noting that a number of individuals were photographed “without

their permission and inferably against their will, while they were

engaged in the peaceful exercise of their First Amendment right to

assemble and [in some cases] to petition their government for a

redress of their grievances.”

512

In Tatum there was only knowledge

of the surveillance program; in contrast, “here there was actual ex-

posure to the challenged police methods.”

513

That, in itself, pro-

vided “proof that actual harm and an actual violation of rights had

occurred.”

514

The Chief of Police in Richmond, Virginia, and those who re-

ported to him, decided which meetings to attend to identify lead-

ers, to track people who may be travelling between meetings to stir

up trouble, to deter violence and vandalism, and to protect peace-

ful demonstrators from counterdemonstrations.

515

Judge Winter

was not persuaded that these objectives were furthered by the prac-

tice of photographing all attendees, or that the same objective

could not be accomplished by means that did not interfere with

otherwise protected First Amendment activities.

516

Law enforce-

ment already knew who the leaders were, which made the efforts to

intimidate the entire crowd concerning. He rejected the possibility

that the police would use the photographs to identify unknown

people.

517

510. Id. at 201.

511. Id. at 200.

512. Id. at 204 (Winter, J., dissenting).

513. Donohoe, 465 F.2d at 205.

514. Id.

515. Id. at 206.

516. Id. at 207.

517. Id. at 206 (“I cannot suppose that every time a picture is taken of an

unknown person it is sent to the FBI in order to determine whether that person is

dangerous.”).

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638 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

Judge Winter’s words appear almost quaint in an age of

drones, big data, and biometric identification. In June 2015, the

Associated Press reported that the Federal Bureau of Investigation

(FBI) was using low-flying planes carrying video and cellphone de-

vices.

518

Over a thirty-day period, the FBI flew the planes over more

than thirty cities in eleven states across the country.

519

Using a

quadcopter fitted with cameras, facial recognition technologies,

and social media, it is conceivable that most people in a crowd

could be instantaneously identified. Yet, under the current doc-

trine, even if a chilling effect might result, it might well be insuffi-

cient to prevent law enforcement from collecting the information.

In the words of Justice Black in 1971:

Where a statute [or police practice] does not directly abridge

free speech, but – while regulating a subject within the State’s

power—tends to have the incidental effect of inhibiting First

Amendment rights, it is well settled that the statute [or police

practice] can be upheld if the effect on speech is minor in rela-

tion to the need for control of the conduct and the lack of

alternative means for doing so.

520

The recording of the information enhances the information be-

yond normal senses, or even the human brain. The data, moreover,

can be combined with other input to construct detailed pictures of

individuals’ lives.

Far from appreciating the privacy interests entailed, the courts

are refusing to acknowledge the considerable interests at stake.

521

In February 2016, the Sixth Circuit Court of Appeals considered a

case in which law enforcement placed a suspect’s home under sur-

veillance for two and a half months.

522

In 2012, the Bureau of Alco-

hol, Tobacco, Firearms and Explosives (ATF) had received a tip

from the local sheriff in Tennessee that Rocky Houston, a convicted

felon, had firearms at his residence. ATF, claiming that they were

unable to observe the farm for any length of time because their cars

“[stuck] out like a sore thumb,” installed a camera at the top of a

public utility pole overlooking his farm.

523

For ten weeks, the cam-

518. Associated Press, FBI Using Low-Flying Spy Planes Over U.S.,

CBS N

EWS

(June 2, 2015), http://www.cbsnews.com/news/ap-fbi-using-low-flying-spy-planes-

over-us/.

519. Id.

520. Younger v. Harris, 401 U.S. 37, 51 (1971).

521. But see United States v. Anderson-Bagshaw, 509 F. App’x 396 (6th Cir.

2012) (expressing “some misgivings” about the constitutionality of long-term war-

rantless surveillance of a backyard via a camera mounted on a pole).

522. United States v. Houston, 813 F.3d 282 (6th Cir. 2016).

523. Id. at 286.

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era broadcast its recordings via an encrypted signal to an IP address

accessed with a login and password.

524

At trial, ATF showed footage

of Houston holding firearms seven times during the ten week

period.

525

The Court dismissed the possibility that any constitutional in-

terest was at stake:

There is no Fourth Amendment violation, because Houston

had no reasonable expectation of privacy in video footage re-

corded by a camera that was located on top of a public utility

pole that captured the same views enjoyed by passersby on pub-

lic roads. The ATF agents only observed what Houston made

public to any person traveling on the roads surrounding the

farm.

526

The length of the surveillance had no effect, “because the Fourth

Amendment does not punish law enforcement for using technology

to more efficiently conduct their investigations.”

527

That technology

made it easier and cheaper to track people for a longer time was of

no consequence. “While the ATF agents could have stationed

agents round-the-clock to observe Houston’s farm in person, the

fact that they instead used a camera to conduct the surveillance

does not make the surveillance unconstitutional.”

528

If a member of the public could observe, with his/her naked

eye, what was happening on the farm, the fact that the same person

could observe it for weeks on end was unremarkable—as was the

fact that the information happened to be recorded. So why could

law enforcement not do the same? And if there was no privacy inter-

est at the outset, then the fact that the observation went on for ten

weeks at a time had little import. Zero plus zero equals zero.

This approach is disturbing in a digital age, in which the pri-

vacy interests implicated by new and emerging tracking technolo-

gies are considerable. It also sidesteps the important role that

resource limitations have previously played in protecting citizens’

privacy. Regardless of who is watching, ten weeks of surveillance im-

plicates a range of privacy interests. As more information can be

obtained from public space about the actions of individuals, incur-

sions into the privacy sphere become deeper. The failure of Fourth

Amendment doctrine lies in its inability to stem the steady constric-

tion of the right to privacy based on the private/public distinction.

524. Id.

525. Id.

526. Id. at 286–88.

527. Id. at 288.

528. Houston, 813 F.3d at 288.

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640 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

IV.

PERSONAL INFORMATION VERSUS THIRD-PARTY

DATA

A second distinction in Fourth Amendment doctrine centers

on the difference between private information and data entrusted

to others. So-called “third-party doctrine” finds its origins in the in-

former cases, where the Court consistently held that information

entrusted to others became divested of any privacy interest.

As aforementioned, in his concurrence in Katz, Justice White

cited to On Lee, Hoffa, and Lopez in support of the proposition that

what is exposed to other people implies an assumption of risk that

the individual in whom one confides will make public what he has

been told. As the Fourth Amendment does not protect against un-

reliable associates, “[i]t is but a logical and reasonable extension of

this principle that a man take the risk that his hearer, free to memo-

rize what he hears for later verbatim repetitions, is instead record-

ing it or transmitting it to another.”

529

White distinguished the

informer cases from Katz, noting that in the case of the gambler, he

had “‘sought to exclude . . . the uninvited ear,’ and spoke under

circumstances in which a reasonable person would assume that un-

invited ears were not listening.”

530

While White’s concurrence sought to preserve the informer

doctrine, it also laid the groundwork for third-party doctrine, which

came to fruition in cases from the 1970s. Miller v. United States

531

and Smith v. Maryland,

532

and their progeny, stand for the proposi-

tion that while an individual may have an interest in information in

her possession, as soon as it is conveyed to a third party, it no longer

enjoys the same protections under the Fourth Amendment.

The concept of secrecy lies at the heart of the doctrine: what

one keeps secret is private, while what one voluntarily exposes to

others is no longer so. Relatedly, the most trenchant criticism of the

private information/third-party data distinction revolves around

the claim of voluntariness. In the contemporary world, it is impossi-

ble to live one’s daily life without entrusting a significant amount of

information to third parties.

533

To say that we therefore voluntarily

529. Katz v. United States, 389 U.S. 347, 363 n.** (1967) (White, J.,

concurring).

530. Id. (quoting id. at 351 (majority opinion)).

531. United States v. Miller, 425 U.S. 435, 443–44 (1976).

532. Smith v. Maryland, 442 U.S. 735, 744 (1979).

533. See Andrew William Bagley, Don’t Be Evil: The Fourth Amendment in the Age

of Google, National Security, and Digital Papers and Effects, 21

. L. J. S

. & T

ECH

153, 154 (2011) (arguing that citizens are increasingly dependent on third party

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 641

assume the risk that such information will be made public denies

the role that technology plays. This phenomenon can be thought of

as “digital dependence.”

A. Information Entrusted to Others

In 1976, the Court took up a critical question raised by Katz,

which was whether the terrestrial distinction drawn at the border of

the home would break down with regard to information held by a

bank. In Miller v. United States, ATF suspected that Mitch Miller had

failed to pay a liquor tax on whiskey and distilling equipment in his

possession.

534

ATF agents served subpoenas on the Citizens and

Southern National Bank of Warner Robins and the Bank of Byron

to obtain Miller’s financial records.

535

The banks subsequently pro-

vided all checks, deposit slips, financial statements, and monthly

statements for grand jury deliberations.

536

Justice Powell, delivering the opinion of the Court, cited back

to Hoffa in support of the idea that an actual intrusion into a private

sphere had to occur for a Fourth Amendment interest to be impli-

cated.

537

He rejected any privacy interest in the records on the

grounds that “checks are not confidential communications but ne-

gotiable instruments to be used in commercial transactions.”

538

Powell underscored the voluntary nature of the relationship be-

tween Miller and the bank: “All of the documents obtained, includ-

ing financial statements and deposit slips, contain only information

voluntarily conveyed to the banks and exposed to their employees

in the ordinary course of business.”

539

Referencing the informer

cases, Powell asserted, “The depositor takes the risk, in revealing his

affairs to another, that the information will be conveyed by that per-

son to the Government.”

540

He concluded, “Since no Fourth

Amendment interests of the depositor are implicated here, this case

is governed by the general rule that the issuance of a subpoena to a

third party to obtain the records of that party does not violate the

service providers for their daily lives and suggesting that companies, in turn, are

becoming increasingly intermingled with government agencies); Brenner, supra

note 78, at 52–59 (underscoring the danger of failing to recognize any privacy

interest in the rapidly expanding amount of information entrusted to third

parties).

534. Miller, 425 U.S. at 436.

535. Id. at 437.

536. Id.

537. Id. at 440.

538. Id. at 442.

539. Id.

540. Miller, 425 U.S. at 443 (citing White, Lopez, and Hoffa).

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642 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

rights of a defendant, even if a criminal prosecution is contem-

plated at the time the subpoena is issued.”

541

Justice Brennan strenuously objected to the Court’s decision.

He noted that the Supreme Court of California, which had a clause

virtually in haec verba as the Fourth Amendment, had come to pre-

cisely the opposite conclusion. In Burrows v. Superior Court, a bank

had voluntarily turned over an accused’s financial records to the

government.

542

The California Supreme Court had determined

that individuals do have a reasonable expectation of privacy in their

bank records, and Brennan agreed: “That the bank alters the form

in which it records the information transmitted to it by the deposi-

tor to show the receipt and disbursement of money on a bank state-

ment does not diminish the depositor’s anticipation of privacy in

matters which he confides to the bank.”

543

The reasonable expecta-

tion was that, absent compulsion via legal process, whatever a cus-

tomer reveals to a bank would only be used for internal banking

purposes.

544

For the Supreme Court of California, whether or not a

bank voluntarily turned its customer’s records over to the police was

irrelevant. Brennan agreed.

Justice Marshall also dissented in Miller, arguing, like Brennan,

that the Bank Secrecy Act, which required banks to maintain cus-

tomers’ records, was unconstitutional on its face.

545

He also pointed

out an apparent irony: while the majority in California Bankers Asso-

ciation v. Shultz had deemed the Fourth Amendment claims to be

too premature to challenge the mandatory recordkeeping provi-

sions in the statute, the Court now concluded that once the banks

had been forced to keep customer records, any effort by the cus-

tomer to assert a Fourth Amendment interest was too late.

546

Three years later, the Court again considered third-party infor-

mation in Smith v. Maryland.

547

In that case, Patricia McDonough

had been robbed.

548

She provided a description of a 1975 Monte

541. Id. at 444.

542. Id. at 447–48 (Brennan, J., dissenting) (citing Burrows v. Superior Court,

529 P.2d 590, 593 (Cal. 1974)).

543. Id. at 448–49.

544. Id. at 449.

545. Id. at 455–56 (Marshall, J., dissenting).

546. Miller, 425 U.S. at 455 (Marshall, J., dissenting) (quoting California

Bankers Ass’n. v. Shultz, 416 U.S. 21, 97 (1974) (Marshall, J., dissenting)).

547. Smith v. Maryland, 442 U.S. 735, 743–44 (1979); see also

ONOHUE

, F

U-

TURE

, supra note 6

at 119–21

;

Donohue, Bulk Metadata, supra note 6, at 868–69

(summarizing Smith).

548. Smith, 442 U.S. at 737.

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Carlo parked at the scene of the crime to the police.

549

When she

returned home, a man telephoned her repeatedly, identifying him-

self as the person who had robbed her, and threatening her.

550

one point, he directed that she come out onto her porch, where

she saw the Monte Carlo drive slowly past her home.

551

McDon-

ough telephoned the police, who saw the vehicle and ran the plates,

determining that it belonged to Michael Lee Smith.

552

They ap-

proached the telephone company and asked if it would be possible

to put a pen register and trap and trace device on Smith’s tele-

phone line to see whether he was the person calling McDon-

ough.

553

The telephone company agreed.

554

Within hours, Smith

again telephoned McDonough. The police used the information to

obtain a search warrant of Smith’s home which, when executed,

yielded a phone book, with a page turned down to McDonough’s

name.

555

Citing New York Telephone Company,

556

the Court noted that the

collection of the numbers dialed from the landline had not inter-

cepted any content.

557

“Given a pen register’s limited capabilities,

therefore,” Justice Blackmun wrote, the argument that the installa-

tion and use of a pen register constituted a search rested upon

whether petitioner had a legitimate expectation of privacy in the

numbers dialed from his phone.

558

The Court determined that he

did not.

559

For the Court, telephone subscribers knew, when dialing, that

they were conveying the numbers to the company, since the infor-

mation was required to connect the call.

560

They further realized

that the company would make records of the numbers dialed.

561

This is what allowed customers to be billed for long-distance

calls.

562

Similarly, even if most people were oblivious as to how tele-

phone companies operated, they would nevertheless have some

549. Id.

550. Id.

551. Id.

552. Id.

553. Id.

554. Smith, 442 U.S. at 737.

555. Id.

556. See discussion, infra.

557. Smith, 442 U.S. at 741.

558. Id. at 742.

559. Id.

560. Id.

561. Id.

562. Id.

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644 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

awareness that a pen register might be employed to identify individ-

uals “making annoying or obscene calls.”

563

The site of the call—in

this case, inside the home—was immaterial:

Although petitioner’s conduct may have been calculated to

keep the contents of his conversation private, his conduct was

not and could not have been calculated to preserve the privacy

of the number he dialed. Regardless of his location, petitioner

had to convey that number to the telephone company in pre-

cisely the same way if he wished to complete his call.

564

Even if the petitioner did have an expectation of privacy, the

Court determined that he did not have one that society was willing

to recognize as reasonable. Citing to Miller, as well as a string of

informer cases (Lopez, Hoffa, and White), Justice Blackmun noted

that the Court had consistently “held that a person has no legiti-

mate expectation of privacy in information he voluntarily turns over

to third parties.”

565

Justice Stewart, joined by Justice Brennan, dissented, as did Jus-

tice Marshall, joined by Justice Brennan.

566

Stewart began by noting

that in the years that had elapsed since Katz, telephones had be-

come even more embedded in contemporary culture.

567

The fact

that the telephone company used the numbers dialed for billing

purposes said nothing about the underlying privacy interests. To

place a call, individuals had to contract with the company. Yet the

Court had recognized a privacy interest in the conversation con-

ducted over the wires—even though the telephone company had

the capacity to record it. Just because individuals also confided the

number dialed to the telephone company, it did not follow that

they necessarily had no interest in the information.

568

“I think,”

Stewart wrote, “that the numbers dialed from a private telephone—

like the conversations that occur during a call—are within the con-

stitutional protection recognized in Katz.”

569

The numbers might

be more prosaic than the actual conversation, but they were “not

without ‘content.’”

570

They could reveal the identities of those with

563. Smith, 442 U.S. at 742.

564. Id. at 743.

565. Id. at 743–44.

566. Id. at 746 (Stewart, J., dissenting); Id. at 748 (Marshall, J., dissenting).

567. Id., 442 U.S. at 746 (Stewart, J., dissenting).

568. Id. at 746–47.

569. Smith, 442 U.S. at 747 (Stewart, J., dissenting).

570. Id. at 748.

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 645

whom an individual was in contact, divulging “the most intimate

details of a person’s life.”

571

Justice Marshall, in turn, attacked the Court’s surmise that sub-

scribers have no subjective expectation of privacy in the numbers

dialed. Even assuming that they know that the company may moni-

tor communications for internal reasons, it did not follow that they

expected the company to turn the numbers dialed over to the pub-

lic or to the government. “Privacy,” he wrote, “is not a discrete com-

modity, possessed absolutely or not at all. Those who disclose

certain facts to a bank or phone company for a limited business

purpose need not assume that this information will be released to

other persons for other purposes.”

572

Marshall raised further concerns that the Court’s holding

meant that those who contract with third parties assume the risk

that the third party might disclose the information to the govern-

ment. He laid forth two objections. First, “[i]mplicit in the concept

of assumption of risk is some notion of choice.”

573

In the informant

cases, this was how the Court had considered the information later

related during court proceedings. But in the case of a pen register,

“unless a person is prepared to forego use of what for many has

become a personal or professional necessity, he cannot help but

accept the risk of surveillance.”

574

It made no sense to talk about

“assuming the risk,” as if it were a choice, when, in order to live in

the contemporary world, one in effect had no choice but to use a

telephone.

Marshall’s second objection was that risk analysis was an inap-

propriate tool. It allowed the government to set the contours of the

Fourth Amendment. Under the Court’s logic, “law enforcement of-

ficials, simply by announcing their intent to monitor the content of

random samples of first-class mail or private phone conversations,

could put the public on notice of the risks they would thereafter

assume in such communications.”

575

The question ought not to be

what risks an individual presumably accepts by providing informa-

tion to third parties, but what risks an individual “should be forced

to assume in a free and open society.”

576

571. Id.

572. Id. at 749 (Marshall, J., dissenting) (citing his own dissent in California

Bankers Assn. v. Shultz, 416 U.S. 21, 95–96 (1974)).

573. Id.

574. Id. at 750.

575. Smith, 442 U.S. at 750 (Marshall, J., dissenting).

576. Id.

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646 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

Marshall’s words proved prescient. He noted that the use of

pen registers constituted “an extensive intrusion. To hold otherwise

ignores the vital role telephonic communication plays in our per-

sonal and professional relationships.”

577

Marshall’s words hear-

kened back to the majority in Katz, which had acknowledged the

“vital role that the public telephone has come to play in private

communication[s].”

578

Increasing dependence on the telephone

meant that Fourth Amendment protections needed to come into

play. For Marshall, the privacy rights of all citizens were at stake:

“The prospect of unregulated governmental monitoring will un-

doubtedly prove disturbing even to those with nothing illicit to

hide. Many individuals, including members of unpopular political

organizations or journalists with confidential sources, may legiti-

mately wish to avoid disclosure of their personal contacts.”

579

The

costs of allowing the government access to such data are borne in

freedom of association and freedom of the press—both hallmarks

“of a truly free society.”

580

The government, moreover, was prone to

abuse such powers: “Particularly given the Government’s previous

reliance on warrantless telephonic surveillance to trace reporters’

sources and monitor protected political activity, I am unwilling to

insulate use of pen registers from independent judicial review.”

581

B. Digital Dependence

In an era of increasing digital dependence, the arguments that

Justices Stewart and Marshall put forth in Smith v. Maryland have

become even more poignant.

582

To say that every time individuals

577. Id. at 751.

578. Katz v. United States, 389 U.S. 347, 352 (1967).

579. Smith, 442 U.S. at 751 (Marshall, J., dissenting).

580. Id.

581. Id. (footnote omitted). Following Miller and Smith, Congress passed two

pieces of legislation that sought to create greater protections of privacy. See gener-

ally 12 U.S.C. §3401 (2013); Electronic Communications Privacy Act of 1986

(ECPA), Pub L. No. 99-508, 100 Stat. 1848 (codified as amended at 18 U.S.C.

§ 2510 (1986)). Further legislation has focused on cable subscriber and video store

customer privacy. See, e.g., Cable Communications Privacy Act of 1984, 47 U.S.C.

§ 551 (2006); Video Privacy Protection Act of 1988, 18 USC § 2710. But these mea-

sures only provide limited protections—and they have quickly become obsolete.

ECPA, for instance, does not apply to the transmission of video. And stored con-

tent is only protected for six months.

582. Some scholars have argued, for similar reasons, for limits on subpoena

powers. See, e.g., Orin S. Kerr, Digital Evidence and the New Criminal Procedure, 105

OLUM

. L. R

279, 309–10 (2005) (suggesting that “[t]he increase in the amount

and importance of information stored with third parties in a network environment

creates the need for new limits on the subpoena power,” and arguing that “new

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 647

use their mobile phone they assume the risk that their data will be

turned over to the government implies that people have no privacy

interest in their communications, regardless of their substance and

any effort to keep the information confidential.

583

But unlike the

informer cases, where one has the capacity to mediate one’s inti-

mate relations, there is no meaningful choice in today’s world as to

whether or not a digital footprint is created as we go about our daily

lives. Every time we make a call, drive our car, send an email, con-

duct an online search, or even walk down the street carrying a mo-

bile device, we leave a trail.

For more than a decade, scholars have written about the

changing world in which we live, raising the alarm that our increas-

ing digital dependence is leading to a loss of privacy.

584

Neverthe-

less, the judiciary has failed to provide a backstop on the steadily

diminishing zone of privacy that results from third party doc-

trine.

585

The Court’s view, however, may be evolving.

In United States v. Jones, Justice Sotomayor suggested in her con-

currence that in light of the deep privacy interests implicated by

data entrusted to third parties, she might jettison third party doc-

rules should respond to the new privacy threats raised by third-party possession of

private information made commonplace by computer networks and the

Internet”).

583. See Brenner, supra note 78, at 68 (“[T]he ‘assumption of risk’ calculus is

an unreasonable methodology for a non-spatial world. It assumes . . . that I have a

choice: to reveal information by leaving it unprotected or to shield it from ‘public’

view. In the real, physical world, these options make sense . . . . But how can I do

this in a world of pervasive technology, a world in which I am necessarily sur-

rounded by devices that collect data and share it with external entities?”).

584. See e.g., Patricia L. Belia & Susan Freiwald, Fourth Amendment Protection for

Stored E-Email, 2008

U. C

. L

EGAL

121, 123–24 (2008); Daniel J. Solove, Digital

Dossiers and the Dissipation of Fourth Amendment Privacy, 75

S. C

. L. R

1083, 1084

(2002); see also Ilana R. Kattan, Note, Cloudy Privacy Protections: Why the Stored Com-

munications Act Fails to Protect the Privacy of Communications Stored in the Cloud, 13

AND

. J. E

. & T

ECH

L. 617, 619 (2011); Christopher R. Orr, Note, Your Digital

Leash: The Interaction Between Cell Phone-Based GPS Technology and Privacy Rights in

United States v. Skinner, 45

U. T

. L. R

377, 377–78 (2014); see generally Bag-

ley, supra note 534; Bellovin et al., supra note 447 at 559, n.8; Marc Jonathan Blitz,

The Fourth Amendment Future of Public Surveillance: Remote Recording and Other Searches

in Public Space, 63

. U. L. R

21, 26 (2013); Marc Jonathan Blitz, Video Surveil-

lance and the Constitution of Public Space: Fitting the Fourth Amendment to a World that

Tracks Image and Identity, 82

. L. R

1349, 1353 (2004); Brenner, supra note

78; Jonathan Zittrain, Searches and Seizures in a Networked World, 119

ARV

. L. R

. F.

83, 83 (2006).

585. Lower courts continue to hold the doctrinal line. See, e.g., United States

v. Graham, 846 F. Supp. 2d 384, 400 (D. Md. 2012).

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648 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

trine altogether.

586

As aforementioned, in Jones, law enforcement

had placed a GPS chip on a car without a warrant and tracked it for

twenty-eight days.

587

Although the Court ruled on grounds of tres-

pass, Sotomayor raised concern about the extent to which surveil-

lance techniques that did not require physical intrusion impacted

significant privacy interests. In light of the ubiquitous nature of dig-

ital technologies, she wrote, “it may be necessary to reconsider the

premise that an individual has no reasonable expectation of privacy

in information voluntarily disclosed to third parties.”

588

Citing to

Smith and Miller, she recognized, “[t]his approach is ill suited to the

digital age, in which people reveal a great deal of information

about themselves to third parties in the course of carrying out mun-

dane tasks.”

589

Sotomayor explained:

People disclose the phone numbers that they dial or text to

their cellular providers; the URLs that they visit and the e-mail

addresses with which they correspond to their Internet service

providers; and the books, groceries, and medications they

purchase to online retailers.

590

Warrantless disclosures of, for instance, every web site visited

over the past year surely held an implication for individual privacy.

“[W]hatever the societal expectations,” Sotomayor contemplated,

“they can attain constitutionally protected status only if our Fourth

Amendment jurisprudence ceases to treat secrecy as a prerequisite

for privacy.”

591

Not to put the point too bluntly, “I would not as-

sume that all information voluntarily disclosed to some member of

the public for a limited purpose is, for that reason alone, disentitled

to Fourth Amendment protection.”

592

586. This view has been supported by a number of scholars. See, e.g., Dono-

hue, supra note 6, at 12; Susan W. Brenner & Leo L. Clarke, Fourth Amendment

Protection for Shared Privacy Rights in Stored Transactional Data, 14

J. L. & P

’

211,

265 (2006). Others favor setting limits to keep it within the confines of the prevail-

ing conditions in Miller and Smith. See, e.g., Patricia L. Bellia, Surveillance Law

Through Cyberlaw’s Lens, 72

. W

ASH

. L. R

. 1375, 1407 (2004); Susan Freiwald,

First Principles of Communications Privacy, 2007

TAN

. T

ECH

. L. R

. 3 ¶ 41 (2007);

Deirdre K. Mulligan, Reasonable Expectations in Electronic Communications: A Critical

Perspective on the Electronic Communications Privacy Act, 72

. W

ASH

. L. R

. 1557,

1578 (2004). Other scholars note that even if we jettison third party doctrine, sig-

nificant difficulties remain. See generally Ohm, supra note 456, at 1330–32.

587. 132 S.Ct. at 948 (Scalia, J.).

588. Id. at 957 (Sotomayor, J., concurring).

589. Id.

590. Id.

591. Id.

592. Id.

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 649

The Supreme Court’s continued emphasis on voluntary disclo-

sure, and not on the government’s requirement that the third party

turn over the information in question, departs from the facts of

Smith with lasting implications for individual rights. In that case,

recall that the telephone company voluntarily relinquished the in-

formation to the government. Had the subscriber contracted with

the company specifically to prevent the information from being for-

warded to others, the individual would have had at least a contrac-

tually-protected right to prevent the information from being made

available. The mere evidence rule, until 1967, would have pre-

vented the forced disclosure of similar information by a warrant.

The Court has, at times, been at pains to distinguish the war-

rant process from the subpoena process. In the 1911 case of Wilson

v. United States, the Court distinguished Boyd v. United States, in

which the production “‘of the private books and papers’ of the

owner of the goods sought to be forfeited” compelled him to be a

witness against himself in violation of the Fifth Amendment and

also amounted to an unreasonable search and seizure under the

Fourth Amendment.

593

By contrast, the use of a “suitably specific

and properly limited” writ, calling “for the production of docu-

ments which, as against their lawful owner to whom the writ is di-

rected, the party procuring its issuance is entitled to have

produced.”

594

It is important to recall here that the context for the subpoena

power was the actual workings of either the grand jury or the

court.

595

The difference between this context, and an investigation

conducted by any law enforcement officer who obtains a warrant to

obtain private information about individuals, is significant, indeed.

By emphasizing the voluntariness of to whom the information is

given, instead of the compulsion then exercised by the government

on the entity providing the information, the Court misses an impor-

tant way in which individual rights would otherwise have been

guarded.

593. Wilson v. United States, 221 U.S. 361, 375 (1911) (quoting Boyd v.

United States, 116 U.S. 616, 634–35 (1886)).

594. Id. at 376.

595. See, e.g., Hale v. Henkel, 201 U.S. 43, 59–60 (1906) (allowing a grand jury

to proceed to issue a subpoena absent a formal charge having been entered and

relying on the oath given to the grand jury—that “you shall diligently inquire and

true presentments make of all such matters, articles, and things as shall be given to

you in charge, as of all other matters, and things as shall come to your own knowl-

edge touching this present service,” etc.—as demonstrating that “the grand jury

was competent to act solely on its own volition”).

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650 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

At the same time, Sotomayor has it right, at least insofar as

modern technology impacts the rights of individual actors.

596

Indi-

viduals do have a clear privacy interest in a range of data entrusted

to corporate entities. But even where information may not appear

to entail a privacy interest at the outset, when accumulated, much

less when analyzed, possibly even in conjunction with other infor-

mation, staggering insight into individuals’ private lives may result.

CONTENT VERSUS NON-CONTENT

As was discussed in Part II(B), prior to Katz, the Court deter-

mined that the contents of a letter deserved higher protection than

the address on the outside of the envelope. This general framing

(content versus non-content) gained ground after Katz. Technol-

ogy, however, is now blurring the doctrinal distinction.

On the one hand, new forms of electronic communication

(such as email, IMs, and text messages), which for all intents and

purposes ought to be considered content, do not fall within the

protections of the Fourth Amendment to the same degree that let-

ters traditionally would—despite the fact that much of the same infor-

mation is at stake.

On the other hand, data traditionally considered to be non-

content, such as pen register and trap and trace data, or envelope

information, in light of digital dependence and the growth of social

network analytics, generates a tremendous amount of information

about individuals’ relationships, beliefs, and predilections—pre-

cisely the interests that the distinction was meant to protect. The

continued reliance on the content/noncontent distinction thus

fails to capture the privacy interests at stake.

A. Electronic Communications

In Katz, the Court confronted whether an individual had a pri-

vacy interest in the contents of an individual’s communications over

596. An argument could be mounted that “secrecy” is to an organization what

“privacy” is to a natural person: namely, the right and the ability to keep individu-

als not part of the entity or privy to the relationship from knowing things. In some

sense, “secrecy” and “privacy” thus represent the same interest expressed by differ-

ent actors. Justice Sotomayor’s formulation, however, considers third party doc-

trine to stand for the proposition that “secrecy” serves “as a prerequisite for

privacy.” The author understands her point as not being to confuse the two, but

rather to suggest that the Constitutional right to individual privacy should not be

premised upon the complete bar of anyone having access to the information in

question.

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 651

a telephone line. In extending protections to the phone booth, the

Court acknowledged the central role that telephones had come to

play in the modern era.

597

Congress followed Katz with introduc-

tion of the 1968 Omnibus Crime Control and Safe Streets Act.

598

Title III laid out the rules that would henceforward govern the elec-

tronic intercepts. The law focused on the content of aural or wire

communications.

While the Court has taken steps to protect the content of tele-

phone communications, it has been slow to recognize a Fourth

Amendment interest in digital communications.

599

The Supreme

Court has not held, for instance, that individuals have a reasonable

expectation of privacy in their e-mail. Instead, this realm is largely

governed by statute.

600

Where the e-mail is located in the chain of

communication alters how much statutory protection it receives. If

an e-mail is sitting on a server and has not yet been read, for in-

stance, it is subject to a different set of procedures than one that

has been read. Similarly, if the e-mail is actually in transit, as op-

posed to just waiting to be read (or having been read), then it re-

ceives different protections. The complex statutes further take into

account considerations such as the type of communications pro-

vider in possession of the information, and the length of time the

communication has been stored.

601

What makes the Court’s failure to recognize a privacy interest

in e-mail remarkable is not only the fact that e-mail conveys a signif-

icant amount of content, but that it lies at the very heart of early

597. Katz v. United States, 389 U.S. 347, 352 (1967); see also Smith v. Mary-

land, 442 U.S. 735, 751 (1973) (Marshall, J., dissenting).

598. See Berger v. New York, 388 U.S. 41, 63–64 (1967) (holding the New

York wiretap law to be unconstitutional, precipitating federal legislation on the

acceptable limits of wiretap authorities).

599. But see City of Ontario v. Quon, 560 U.S. 746, 762–63 (2010) (suggesting

that “a search of [someone’s] personal email account” would be as intrusive as “a

wiretap on his home phone line”).

600. Within the Electronic Communications Privacy Act (ECPA), the Wiretap

Act, 18 U.S.C. §§ 2510-22 governs the interception of e-mail communications en

route while the Stored Communications Act, 18 U.S.C. §§ 2701–12 (2012) regu-

lates e-mails stored by certain entities.

601. For a good discussion of the different aspects of ECPA as applied to elec-

tronic communications, see generally

LANCY

, supra note 79, at § 1.5. These nuances

run counter to the Court’s approach in Ex parte Jackson, discussed infra, in which

the mere fact that a letter had left the home did little to alter the privacy interests

entailed. An effort to amend the SCA failed in December 2012, when the Senate

removed from proposed legislation a measure that would have stopped federal law

enforcement from warrantless acquisition of e-mail. Adrian Fontecilla, The Ascen-

dance of Social Media as Evidence, 28

RIM

. J

USTICE

1, 2

(2013).

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652 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

21st century communications. By 2011, ninety percent of those us-

ing the Internet had sent or received e-mail, with half of the U.S.

population using it daily.

602

E-mail has essentially replaced the pa-

per correspondence at issue in Ex parte Jackson.

In the meantime, the lower courts remain divided. Some have

come out in support of the proposition that e-mail falls within the

remit of the Fourth Amendment. In 2008, the Ninth Circuit in

United States v. Forrester recognized that “[t]he privacy interests in

[letters sent through the post and email] are identical.”

603

Two

years later, the Sixth Circuit Court of Appeals catapulted the con-

versation forward in United States v. Warshak, finding that individuals

do, indeed, have a reasonable expectation of privacy in their e-

mail.

604

Steven Warshak owned a company that sold an enormously

popular product.

605

Its auto-ship program, however, failed to warn

consumers that by requesting a free sample, they were being en-

rolled in a delivery schedule from which they would have to opt out

to avoid being charged.

606

As complaints mounted, a grand jury re-

turned a 112-count indictment against Warshak, ranging from mail,

wire, and bank fraud, to money laundering.

607

In the course of its

investigation, the government obtained 27,000 e-mails from War-

shak’s Internet Service Providers.

608

On appeal, Warshak argued

that the warrantless seizure violated the Fourth Amendment.

609

The Court ultimately agreed, although it determined that, in this

case, the government had relied in good faith on the Stored Com-

munications Act, leaving the judgment undisturbed.

610

In finding a Fourth Amendment interest, the Court observed,

“[E]-mail was a critical form of communication among Berkeley

602.

RISTEN

URCELL

ESEARCH

ENTER

EARCH AND

MAIL

TILL

THE

IST OF

OST

OPULAR

NLINE

CTIVITIES

(Aug. 9, 2011), http://pewinternet

.org/Reports/2011/Search-and-email.aspx; Matthew A. Piekarski, E-mail Content’s

Brush with the Reasonable Expectation of Privacy: The Warshak Decision, 47

U. L

OUIS-

VILLE

L. R

771, 795 (2009).

603. United States v. Forrester, 512 F.3d 500, 511 (9th Cir. 2008).

604. United States v. Warshak, 631 F.3d 266, 274 (6th Cir. 2010).

605. Id. at 276. The product, Enzyte was “purported to increase the size of a

man’s erection.” As the court noted, “[t]he product proved tremendously popular,

and business rose sharply.” By 2004, the company was making around $250 million

per year.

606. Id. at 278.

607. Id. at 278, 281.

608. Id. at 282.

609. Id.

610. Warshak, 631 F.3d 266, at 282.

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 653

personnel.”

611

Warshak, in particular, expected “that his emails

would be shielded from outside scrutiny.”

612

The Court continued,

“given the often sensitive and sometimes damning substance of his

e-mails, we think it highly unlikely that Warshak expected them to

be made public, for people seldom unfurl their dirty laundry in

plain view.”

613

The court underscored the relationship between written

materials, telephone calls, and Internet communications. The

growth of society’s dependence on e-mail had shrunk the role of

telephone calls and letters:

People are now able to send sensitive and intimate informa-

tion, instantaneously, to friends, family, and colleagues half a

world away. Lovers exchange sweet nothings, and businessmen

swap ambitious plans, all with the click of a mouse button.

Commerce has also taken hold in email. Online purchases are

often documented in email accounts, and email is frequently

used to remind patients and clients of imminent appoint-

ments. . . . By obtaining access to someone’s email, govern-

ment agents gain the ability to peer deeply into his activities.

614

The Fourth Amendment had to “keep pace with the inexorable

march of technological progress, or its guarantees” would “wither

and perish.”

615

“Over the last decade,” the Sixth Circuit explained, “email has

become ‘so pervasive that some persons may consider [it] to be

[an] essential means or necessary instrument[ ] for self-expression,

even self-identification.’”

616

It required strong protections, without

which the Fourth Amendment would not prove an effective guard-

ian of private communication. It was not so much that e-mail had

become an additional type of communication, as that it appeared to

be replacing the traditional modes of communication, which in-

creased the need for it to be protected.

The fact that the e-mail passed through an ISP was irrelevant.

“If we accept that an e-mail is analogous to a letter or phone call, it

is manifest that agents of the government cannot compel a com-

mercial ISP to turn over the contents of an e-mail without trigger-

611. Id. at 283.

612. Id. at 284.

613. Id.

614. Id.

615. Id. at 285.

616. Warshak, 631 F.3d at 286 (quoting City of Ontario v. Quon, 560 U.S. 746,

760 (2010)).

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654 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

ing the Fourth Amendment.”

617

The ISP was an intermediary—the

functional equivalent of a post office or telephone company. Just as

law enforcement could not walk into a post office or a telephone

company to demand the contents of letters or phone calls, neither

could it demand that an ISP turn over e-mails absent a warrant.

Even as Sixth Circuit extended its protections to e-mail, it re-

lied on the traditional content/non-content distinction. The court

hastened to distinguish Miller, which involved “simple business

records” used “in the ordinary course of business.”

618

In contrast,

the e-mails sent and received by Warshak were not directed to the

ISP as an “intended recipient.”

619

The U.S. Court of Appeals for the Armed Forces (USCAAF)

reached a similar conclusion with regard to the content of e-mails.

In United States v. Long, it held that Lance Corporal Long had both

an objective and a subjective expectation of privacy in e-mails re-

trieved from a government server.

620

The e-mails indicated that she

had been afraid that “her drug use would be detected by urinalysis

testing,” and documented the steps she had taken to try to avoid

discovery.

621

USCAAF looked to O’Connor v. Ortega, in which the Supreme

Court had recognized that government employees may have a rea-

sonable expectation of privacy.

622

In Long, USCAAF acknowledged

that the military workplace was not exactly the type of environment

pictured in O’Connor (which had involved a physician at a state hos-

pital).

623

Nevertheless, military personnel could, under some cir-

cumstances, have a reasonable expectation of privacy in their e-

mail.

624

Long had used a password (one that the network adminis-

617. Id.

618. Id. at 288 (quoting United States v. Miller, 425 U.S. 435, 442 (1976)).

619. Id.

620. United States v. Long, 64 M.J. 57, 59 (C.A.A.F. 2006).

621. Id.

622. Id. at 61 (citing O’Connor v. Ortega, 480 U.S. 709, 716 (1987) (plurality

opinion)). In O’Connor, the Court acknowledged that the reasonable expectation

could be reduced with regard to the employee’s office, desk, or filing cabinet in

accordance with the “efficient and proper operation of the agency.” It also recog-

nized a lesser expectation where the search by the employer was related to work-

place misconduct. O’Connor 480 U.S. at 720–22 (plurality opinion).

623. Long, 64 M.J. at 62; O’Connor, 480 U.S. at 712.

624. Long, 64 M.J. at 64. See, e.g., United States v. Maxwell, 45 M.J. 406, 417

(C.A.A.F. 1996) (holding that Maxwell possessed a reasonable expectation of pri-

vacy in an America Online e-mail account). But see United States v. Monroe, 52

M.J. 326, 330 (C.A.A.F. 2000) (finding that because the e-mail system in question

was owned by the government, Monroe had no contractual agreement guarantee-

ing privacy from those maintaining the e-mail system).

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 655

trator did not know) to access her account, establishing an expecta-

tion of privacy in her communications.

625

The fact that the e-mails

were originally prepared in an office in Marine Corps’ headquar-

ters (HQMC), on a computer owned by the Marine Corps, and that

the e-mails had been transmitted over the HQMC network, stored

on the HQMC server, and retrieved by the HQMC network admin-

istrator, did not erode Long’s Fourth Amendment rights.

626

Although the Ninth and Sixth Circuits, and USCAAF, have ex-

tended an expectation of privacy to e-mail, others, looking at the

“totality of the circumstances” have come to a different conclusion.

In United States v. Simons, the Fourth Circuit relied upon the CIA’s

Foreign Bureau of Information Services’s Internet policy, which re-

stricted employees’ use of the system to official government busi-

ness and informed them of ongoing audits, to find that the Fourth

Amendment did not apply.

627

The policy provided fair warning to

employees and contractors that their use of the system might be

monitored, even as it established the limits of how the system could

be used. As a result, a government contractor who used the network

to access and download photos from pornographic web sites could

not claim the protection of the Fourth Amendment.

628

The Fourth Circuit again determined in United States v. Richard-

son that AOL e-mail scans to detect child pornography, and the pro-

vision of that information to law enforcement, did not raise the

specter of the Fourth Amendment.

629

AOL initiated its own pro-

cess, outside of any government direction or control. As federal law

enforcement neither required AOL to place e-mails under surveil-

lance, nor directed how such searches should be conducted, no

constitutional right came into being. The Fourth Amendment did

not restrain private industry.

Similarly, in United States v. Angevine, the Tenth Circuit consid-

ered Oklahoma State University’s log-on banner, which expressly

disclaimed any right of privacy or confidentiality.

630

Together with

“a computer policy that explains the appropriate computer use,

warns employees about the consequences of misuse, and describes

how officials monitor the University network,” the banner provided

625. Long, 64 M.J. at 64–65.

626. Id. at 64.

627. United States v. Simons, 206 F.3d 392, 396 (2000).

628. Id.

629. U.S. v. Richardson, 607 F.3d 357, 364, 367 (4th Cir. 2010).

630. 281 F.3d at 1130, 1133 (2002).

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656 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

sufficient notice to users that Fourth Amendment protections did

not apply.

631

As for text messages, as a doctrinal matter, it is far from clear

whether they fall within Fourth Amendment protections. In 2010,

the Supreme Court heard City of Ontario v. Quon, a case that cen-

tered on whether a government employer could read text messages

sent and received on a pager owned by the government and issued

to an employee.

632

In considering the reasonableness of the search

Justice Kennedy, writing for the Court, recognized, “[C]ell phone

and text message communications are so pervasive that some per-

sons may consider them to be essential means or necessary instru-

ments for self-expression, even self-identification.”

633

acknowledged, “[T]hat might strengthen the case for an expecta-

tion of privacy.” But the very fact that the technology was so com-

mon and inexpensive meant that “employees who might need cell

phones or similar devices for personal matters can purchase and

pay for their own.”

634

Employer policies, in turn, would shape the

reasonableness of any expectations of privacy. The SWAT officer,

whose messages had been read, had been told that he did not have

any privacy rights in the pager system provided by the City of Onta-

rio, California.

635

The Court did not address whether the content of

text messages was protected.

At least one state supreme court has come to the conclusion

that text messages do not trigger Fourth Amendment protections.

In 2012, a lower Rhode Island state court held in State v. Patino that

the defendant did have a reasonable expectation of privacy in the

text messages sent and received.

636

In June 2014, the Rhode Island

Supreme Court reversed the lower court’s opinion.

637

In Patino, police responded to a 911 call for a child who had

stopped breathing.

638

Once the child was in the ambulance on the

way to the hospital, the police looked through the mother’s cell

phone, which was laying on a kitchen countertop, and found texts

631. Id.

632. 560 U.S. 746 (2010).

633. Id. at 760.

634. Id.

635. Id. at 762 (“Even if he could assume some level of privacy would inhere

in his messages, it would not have been reasonable for Quon to conclude that his

messages were in all circumstances immune from scrutiny. Quon was told that his

messages were subject to auditing.”).

636. State v. Patino, No. P1-10-1155A, 2012 WL 3886269 (R.I. Super. Sept. 4,

2012), aff’d in part, vacated in part, 93 A.3d 40 (R.I. 2014).

637. State v. Patino, 93 A.3d 40 (R.I. 2014).

638. Id. at 43.

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 657

that incriminated the mother’s boyfriend, Michael Patino.

639

The

question before the court was whether individuals have a reasona-

ble expectation of privacy in texts stored on others’ cell phones.

640

The court found that the reasonableness prong turned on

whose phone was accessed.

641

Control mattered. “[W]hen the recip-

ient receives the message,” the court explained, “the sender relin-

quishes control over what becomes of that message on the

recipient’s phone.”

642

Once the content of the message was re-

vealed to another person, the sender lost any reasonable expecta-

tion of privacy. In this case, the police had accessed the owner’s

phone without her consent, although she had later signed a form

allowing the police to search the device.

643

But for the Court, the

sender had already relinquished any privacy interest and thus lacked

standing to challenge the search and seizure of his messages.

644

The Supreme Court has not affirmatively identified a Fourth

Amendment interest in e-mail or text messages—to say nothing of

instant messaging, or the myriad other ways that messages may be

conveyed through apps, games, and other digital means.

In the 2014 case of Riley v. California, the Supreme Court was

willing to acknowledge that a generalized privacy interest attached

to a mobile phone in a search incident to arrest.

645

The case did

not distinguish between the text messages on a phone and other

functions, such as emails, address books, social media, or gaming

applications.

646

Instead, it made a general argument that an im-

mense amount of private information could be carried on a mobile

device.

647

Several consequences for individual privacy followed:

First, a cell phone collects in one place many distinct types of

information that reveal much more in combination than any

isolated record. Second, the phone’s capacity allows even just

one type of information to convey far more than previously

possible. Third, data on the phone can date back for years. In

639. Id. at 45.

640. Id. at 55.

641. Id.

642. Id.

643. Patino, 93 A.3d at 56.

644. Id. at 57.

645. Riley v. California, 134 S. Ct. 2473, 2478 (2014).

646. Id.

647. Id. (“[M]odern cell phones have an immense storage capacity . . . .

[They] can store millions of pages of text, thousands of pictures, or hundreds of

videos.”)

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658 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

addition, an element of pervasiveness characterizes cell phones

but not physical records.

648

A generalized interest in cell phones, however, does not clearly

establish the privacy interests that reside in the communication of

digital content as transferred through e-mail, text messaging, and

other means.

B. Pen Register/Trap and Trace Devices

Even as Supreme Court jurisprudence has, to date, failed to

protect digital communications that look like traditional content,

the growth of new technologies challenges the definition of certain

types of non-content, because of the amount of content that they

now convey. Perhaps the most ready example of this are pen regis-

ter and trap and trace devices which the Court, in the aftermath of

Katz, placed on the non-content side of the dichotomy. With the

advance of technology and new algorithmic analyses, this type of

information increasingly reveals intimate details about individuals’

lives.

The first case directly on point arose in 1977, when the Court

looked at whether a district court could direct a telephone com-

pany to assist in placing a pen register on a telephone line.

649

The

Southern District of New York had issued an order authorizing the

FBI to direct the telephone company to monitor two telephone

lines, compensating the company for any assistance it was thereby

forced to provide.

650

In United States v. New York Telephone Co., the

Court noted that the language of Title III did not cover the use of

pen registers.

651

To the contrary, it was concerned only with orders

“authorizing or approving the interception of a wire or oral commu-

nication.”

652

Pen registers, the Court reasoned, “do not ‘intercept,’

because they do not acquire the ‘contents’ of communications.”

653

The Court borrowed its understanding of “contents” from the stat-

ute itself, which understood it to include “any information concern-

ing the identity of the parties to [the] communication or the

existence, substance, purport, or meaning of [the] communica-

tion.”

654

The Court cited the Senate Report, which explicitly dis-

648. Id. at 2478–79.

649. United States v. N.Y. Tel. Co., 434 U.S. 159, 161 (1977).

650. Id.

651. Id. at 166.

652. Id. (citing 18 U.S.C. § 2518(1)(1998) (emphasis added)).

653. Id. at 167.

654. Id. (citing 18 U.S.C. § 2518(1)(1998)).

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 659

cussed that the law was meant to exclude pen registers.

655

The

action in question was consistent with the All Writs Act.

656

Justice White, writing for the Court, outlined a number of con-

siderations that made the use of the All Writs Act acceptable under

the circumstances. First, the telephone company was not “a third

party so far removed from the underlying controversy that its assis-

tance could not be permissibly compelled.”

657

Second, the Court

had found probable cause that the facilities were being used to fa-

cilitate criminal activity on an ongoing basis.

658

Third, the assis-

tance requested was “meager.”

659

Fourth, the company was already

“a highly regulated public utility with a duty to serve the public.”

660

Fifth, “the use of pen registers” was “by no means offensive” to the

telephone company.

661

Sixth, the company itself regularly used pen

registers to check its billing operations, detect fraud, and prevent

illegal activities.

662

Seventh, the order was not in any way burden-

some, as it “provided that the Company be fully reimbursed at pre-

vailing rates, and compliance with it required minimal effort on the

part of the company and no disruption to its operations.”

663

Eighth,

without the company’s assistance, the FBI could not have carried

out its wishes.

664

Justices Stevens, Brennan, Marshall, and Stewart all dissented

in part from the Court’s opinion.

665

Justice Stevens raised particular

concern about jumping from the omission of pen registers and trap

and trace devices in Title III to the conclusion that they were consti-

655. N.Y. Tel. Co., 434 U.S. at 167–68 (quoting S. Rep. No. 90-1097, 90th

Cong., 2d Sess. (1968) (“Paragraph 4 defines ‘intercept’ to include the aural acqui-

sition of the contents of any wire or oral communication by any electronic,

mechanical, or other device. Other forms of surveillance are not within the pro-

posed legislation. . . . The proposed legislation is not designed to prevent the trac-

ing of phone calls. The use of a ‘pen register,’ for example, would be permissible.

But see United States v. Dote, 371 F.3d 176 (7th 1966). The proposed legislation is

intended to protect the privacy of the communication itself, and not the means of

communication.”)).

656. Id. at 172 (“The Supreme Court and all courts established by Act of Con-

gress may issue all writs necessary or appropriate in aid of their respective jurisdic-

tions and agreeable to the usages and principles of law.”) (quoting the All Writs

Act, 28 U.S.C. § 1651(a) (2012)).

657. Id. at 174.

658. Id.

659. Id.

660. Id.

661. N.Y. Tel. Co., 434 U.S. at 174.

662. Id. at 174–75.

663. Id. at 175.

664. Id. at 174–75.

665. Id. at 178.

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660 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

tutionally authorized.

666

He pointed to dicta in Katz, which under-

scored that Rule 41 was not tied to tangible property.

667

The content/non-content distinction highlighted in New York

Telephone Co. persisted. The following year, in Smith v. Maryland, the

Court returned to the function of pen registers as representing

non-content, quoting New York Telephone Co. in support:

[A] law enforcement official could not even determine from

the use of a pen register whether a communication existed.

These devices do not hear sound. They disclose only the tele-

phone numbers that have been dialed—a means of establish-

ing communication. Neither the purport of any

communication between the caller and the recipient of the

call, their identities, nor whether the call was even completed

is disclosed by pen registers.

668

Pen registers, and by inference trap and trace devices, represented

non-content.

In an age of metadata and social network analytics, however, it

simply is not true that data obtained via pen registers or trap and

trace devices do not represent content.

669

A tremendous amount of

information can be gleaned just from the numbers dialed and re-

ceived by one’s telephone. At the most obvious level, the numbers

one dials reveal hobbies, interests, relationships, and beliefs. Con-

tacting a drone manufacturer, or a 3D printer sales line shows an

interest in drones and 3D printing. Calling a local political repre-

sentative and members of the planning commission may show con-

cern about development plans in the works. Repeated calls to a

priest, rabbi, or imam—or to a church, synagogue, or mosque—

may suggest religious conviction.

Communication patterns also reveal degrees of intimacy. Fre-

quent contact with an individual denotes a closer relationship than

those with whom one rarely interacts. Mapping the strength of

these relationships, in turn, help to elucidate broader social net-

666. Id. at 179.

667. N.Y. Tel. Co., 434 U.S. at 182–86.

668. 442 U.S. 735, 741 (1979) (quoting N.Y. Tel. Co., 434 U.S. at 167).

669. Professor Orin Kerr has argued that while “the contents of online com-

munications . . . should receive Fourth Amendment protection . . . non-content

information should not be protected.” Orin S. Kerr, Applying the Fourth Amendment

to the Internet: A General Approach, 62

TAN

. L. R

1005, 1007–08 (2010). The au-

thor disagrees with this argument on the grounds that the line between content

and non-content, in a digital age, is often indiscernible. See, e.g., Laura K. Dono-

hue, The Dawn of Social Intelligence (SOCINT), 63

RAKE

L. R

1061, 1065 (2015).

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 661

works and an individual’s relationship to others in the network.

670

From this, leaders can be identified. By mapping social networks,

critical connections between different groups also can be

identified.

671

In June 2013, an associate professor of sociology at Duke Uni-

versity posted a provocative article, Using Metadata to Find Paul Re-

vere, to illustrate the power of social network analytics.

672

Basing his

analysis on the organizations to which the American Revolutionists

belonged, Professor Kieran Healy identified shared membership of

key organizations, in this manner uncovering the strength of rela-

tionships between key revolutionary groups. Breaking down his

analysis further into the strength of individuals within and among

organizations, Paul Revere emerges as the linchpin.

673

And Healy

went further, calculating the eigenvector centrality number to eval-

uate the power of the various revolutionists, composing a short list

of individuals who would be “persons of interest” to the Crown.

674

neatly captured the most important members of the Revolution.

Numerous studies similarly highlight that metadata reveals a tre-

mendous amount of content, making Fourth Amendment doctrine

appear almost quaint in a digital age.

675

C. Envelope Information

Envelope information historically has not been considered

within the gamut of the Fourth Amendment. Following Katz, the

Court reiterated its protection of letters and packages.

676

Like com-

munications placed inside envelopes, sealed packages provided to

private carriers constitute “effects” within the meaning of the

670. See generally Greg Statell, How the NSA Uses Social Network Analysis to Map

Terrorist Networks,

IGITAL

ONTO

(June 12, 2013), http://www.digitaltonto.com/

2013/how-the-nsa-uses-social-network-analysis-to-map-terrorist-networks/.

671. Ronald L. Breiger, The Duality of Persons and Groups, 53

OCIAL

ORCES

181, 181–82 (1974).

672. Kieran Healy, Using Metadata to Find Paul Revere,

IERAN

EALY

LOG

(June 9, 2013), https://kieranhealy.org/blog/archives/2013/06/09/using-

metadata-to-find-paul-revere/.

673. Id.

674. Id.

675. See, e.g., Declaration of Professor Edward W. Felten, ACLU v. Clapper,

959 F. Supp. 2d 724 (2013) (no. 13-cv-03994); Jonathan Mayer & Patrick Mutchler,

MetaPhone: The Sensitivity of Telephone Metadata,

OLICY

(Mar. 12, 2014), http:/

/webpolicy.org/2014/03/12/metaphone-the-sensitivity-of-telephone-metadata/;

see also Clifton B. Parker, Stanford Students Show that Phone Record Surveillance Can

Yield Vast Amounts of Information,

TANFORD

EPORT

(Mar. 12, 2014), http://

news.stanford.edu/news/2014/march/nsa-phone-surveillance-031214.html.

676. Walter v. United States, 447 U.S. 649, 654 (1980).

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662 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

Fourth Amendment.

677

What is written on the outside of the envel-

ope or the package, though, does not enjoy a reasonable expecta-

tion of privacy. Underlying this approach is the basic concept that

what one exposes to others who can simply observe the object, per-

son, or behavior in question, does not fall within the Fourth

Amendment. It is bolstered by the assumption that the address

merely conveys to/from data—not content itself.

In an age of Internet communications, however, the argument

that envelope information does not involve content breaks down. E-

mail subject lines may carry significant details about the content of

the messages themselves. Uniform Resource Locators (URLs) re-

veal the content of the pages for which one searches—and, there-

fore, what one reads. URLs reflect both the specific page being

read and the website in general. Website IP addresses similarly re-

veal content. Yet the courts have yet to recognize the content con-

veyed through these digital resources, leaving electronic data

unprotected from private or government intrusion.

678

In the in-

terim, the government is seeking access to Internet browser history

without a warrant.

679

In United States v. Hambrick, the Fourth Circuit concluded that,

under Smith, subscriber information conveyed to an ISP to set up

an e-mail account was not protected.

680

The Ninth Circuit similarly

held that the “to” or “from” addresses on e-mail, IP addresses of

websites, or the total volume of file transfers linked to an Internet

account, did not fall within the Fourth Amendment.

681

In United

States v. Forrester, the Ninth Circuit focused on the distinction in

Smith between content and non-content, concluding that the re-

cording of IP addresses functioned as the constitutional equivalent

of the pen registers in Smith.

682

The Court did acknowledge that

the collection of not just website IP addresses but also URLs of

677. United States v. Jacobsen, 466 U.S. 109, 114 (1984).

678. Matthew J. Tokson, The Content/Envelope Distinction in Internet Law, 50

. & M

ARY

L. R

2015, 2110–11 (2009).

679. See, e.g., Ellen Nakashima, FBI Wants Access to Internet Browser History With-

out a Warrant in Terrorism and Spy Cases,

ASH

. P

OST

(June 6, 2016), https://

www.washingtonpost.com/world/national-security/fbi-wants-access-to-internet-

browser-history-without-a-warrant-in-terrorism-and-spy-cases/2016/06/06/2d2573

28-2c0d-11e6-9de3-6e6e7a14000c_story.html.

680. United States v. Hambrick, No. 99-4793, 2000 WL 1062039, at *4 (4th

Cir. Aug. 3, 2000).

681. United States v. Forrester, 495 F.3d 1041, 1048–49 (9th Cir. 2007).

682. Id.

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pages visited “might be more constitutionally problematic,” but it

did not directly address the question.

683

The Seventh Circuit came to a similar conclusion in United

States v. Caira, finding that the government was not required to first

get a search warrant before obtaining a suspect’s IP address and

684

Caira’s efforts to draw a

parallel to the GPS chip in Jones fell short: “The government re-

ceived no information about how he got from home to work, how

long he stayed at either place, or where he was when he was not at

home or work. On days when he did not log in, the government

had no idea where he was.”

685

The cCourt acknowledged Justice

Sotomayor’s Jones concurrence, and her willingness to dispense

with Third Party Doctrine altogether, but it also noted that the Su-

preme Court had yet to embrace her position.

686

Nevertheless, just

as the GPS chip in Jones conveyed a significant amount of private

information, so, too, do IP addresses and login histories.

One response to the privacy implications of collecting all of

this data may be to simply assume that all digital information is con-

tent—driving the discussion to whether the information is public or

private. Another response might be to say that no digital informa-

tion is content. But this, too, ignores the deep privacy interests con-

veyed through bits and bytes. The current approach seeks to sort

out the massive gray area between these two extremes. But simply

re-entrenching the content/non-content distinction will not ad-

dress the longer-term concern: how to protect the privacy interests

at stake.

VI.

DOMESTIC VERSUS INTERNATIONAL

A final distinction that is breaking down in light of new and

emerging technologies centers on the line between domestic and

international. Until the mid-20th century, it was generally assumed

that the Bill of Rights did not apply outside the United States, even

when law enforcement sought to prosecute citizens for criminal ac-

tivity overseas.

687

As the country expanded, only the territories that

683. Id. at 1049.

684. United States v. Caira, 833 F.3d 803, 809 (7th Cir. 2016).

685. Id. at 808.

686. Id. at 809

687. See, e.g., In re Ross, 140 U.S. 453, 464 (1891) (holding that the Fourth

Amendment was limited to domestic bounds); see also Jennifer Daskal, The Un-Terri-

toriality of Data, 125

ALE

L. J. 326, 336

(2015); Caitlin T. Street, Note, Streaming the

International Silver Platter Doctrine: Coordinating Transnational Law Enforcement in the

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664 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

were destined for statehood enjoyed the full protection of the Bill

of Rights. Those that would remain unincorporated territories only

enjoyed the protection of fundamental rights—understood in 1901

as including those “inherent, although unexpressed, principles

which are the basis of all free government.”

688

In 1957, the Su-

preme Court shifted its position, suggesting that the Bill of Rights

applied to U.S. citizens abroad.

689

In the decades after Katz, scholars began debating the univer-

sal application of the Bill of Rights.

690

Some lower courts began

moving in this direction as well.

691

But the optimism proved short-

lived. In 1990, the Supreme Court issued an opinion limiting the

application of the Fourth Amendment overseas.

692

There were good reasons for drawing a line. The uncertainties

of investigations overseas, the delicacy involved in diplomatic ex-

changes, the risk of tipping off criminals with political and other

ties to foreign governments, questions of jurisdiction, and other

concerns suggested that the same standards that marked the do-

mestic realm should not apply outside U.S. bounds. Resultantly, the

Court eschewed a warrant requirement, falling back upon the rea-

sonableness standard for U.S. persons abroad. For non-U.S. persons

abroad lacking a significant connection to the United States, the

Age of Global Terrorism and Technology, 49

OLUM

. J. T

RANSNAT

’

411, 429

(2010–2011). Thus, while the Fourth Amendment applied within the United

States—regardless of whether the individual targeted was a U.S. citizen or not—it

did not apply outside U.S. borders. See, e.g., Sardino v. Fed. Reserve Bank of N.Y.,

361 F.2d 106, 111 (2d Cir. 1966) (“The Government’s [argument] that ‘The Con-

stitution of the United States confers no rights on non-resident aliens’ is so pa-

tently erroneous in a case involving property in the United States that we are

surprised it was made.”), cited in Daskal, supra at 336 n.22.

688. Downes v. Bidwell, 182 U.S. 244, 291 (1901) (White, J., concurring).

689. Reid v. Covert, 354 U.S. 1, 5–6 (1957) (“The United States is entirely a

creature of the Constitution. Its power and authority have no other source. It can

only act in accordance with all the limitations imposed by the Constitution. When

the Government reaches out to punish a citizen who is abroad, the shield which

the Bill of Rights and other parts of the Constitution provided to protect his life

and liberty should not be stripped away just because he happens to be in another

land.”).

690. See, e.g., Daskal, supra note 690, at 337–38; Louis Henkin, The Constitution

as Compact and as Conscience: Individual Rights Abroad and at Our Gates, 27

. &

ARY

L. R

11, 34 (1985); Jules Lobel, Here and There: The Constitution Abroad, 83

. J. I

’

871, 879 (1989); Paul B. Stephan III, Constitutional Limits on the

Struggle Against International Terrorism: Revisiting the Rights of Overseas Aliens, 19

ONN

. L. R

. 831 (1987).

691. See, e.g., United States v. Conroy, 589 F.2d 1258, 1264 (5th Cir. 1979);

United States v. Rose, 570 F.2d 1358, 1361–62 (9th Cir. 1978).

692. United States v. Verdugo-Urquidez, 494 U.S. 259, 261 (1990).

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Fourth Amendment did not apply at all.

693

This, too, made sense,

not just because of practical considerations, but also because a plau-

sible reading of the Fourth Amendment understands “the people”

to refer to citizens of the United States (see discussion, infra).

In the realm of national security, looser Fourth Amendment

standards framed the collection of foreign intelligence within U.S.

bounds.

694

Nevertheless, as in criminal law, the courts drew a line at

the border, with no Fourth Amendment protections extended to

U.S. persons located overseas.

695

In 2008, Congress took the first

steps to acknowledge citizens’ privacy interests outside the country.

However, weaker standards apply than those that mark domestic

collection.

696

The problem is that persistent reliance on the borders of the

country to protect citizens’ constitutional rights fails to recognize

that global communications systems run rampant over the domes-

tic/international distinction. Where, previously, individuals would

have to physically travel internationally, or deliberately put in tele-

phone calls to other countries, thus entailing some level of knowl-

edge that what one said or did was leaving the United States, today

bits and bytes simply follow the most efficient route—without any

deliberate action on the part of the individual generating the infor-

mation. Much of the information generated internationally, moreo-

ver, is ultimately held in the United States or by U.S. entities—

rather undermining the arguments that it is unpractical to obtain

the same information, or that it would somehow alert foreign gov-

ernments or criminals, by first requiring a warrant. Similarly, the

implications for the jurisdictional argument fall away.

Nevertheless, because of the nature of global communications,

and where the information is generated, the same types of commu-

nications that previously would have been protected are now more

vulnerable to monitoring, interception, and collection by the gov-

ernment—simply because we live in a digital age.

693. Id. at 271.

694. Compare Title III of the Omnibus Crime Control and Safe Streets Act of

1968, Pub. L. 90-351, 82 Stat. 197, codified at 18 U.S.C. §§ 2510-22 (standards for

surveillance in the United States), with Foreign Intelligence Surveillance Act of

1978, Pub. L. 95-511, 92 Stat. 1783, codified at 50 U.S.C. § 1801 (standards for

surveillance outside of the United States). See also discussion, infra pp. 86–88.

695. The 1978 Foreign Intelligence Surveillance Act purely addressed the col-

lection of information on U.S. soil. Collection overseas fell within the broader

framing of Executive Order 12,333.

696. Foreign Intelligence Surveillance Act of 1978 Amendments Act of 2008,

Pub. L. 110-261, 122 Stat. 2436, July 10, 2008.

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666 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

A. Law Enforcement

In 1990, the Supreme Court decided in United States v. Verdugo-

Urquidez that non-U.S. citizens, who lack a substantial connection to

the United States, do not enjoy the protections of the Fourth

Amendment.

697

The DEA had conducted a warrantless search of

Mexicali and San Felipe residences of a Mexican citizen.

698

Chief

Justice Rehnquist, writing for the Court, suggested that the right of

“the people” meant those who made up the political community of

the United States—not non-citizens abroad, lacking a “substantial

connection” to the country.

699

Justice Kennedy, in his concurrence, pointed to the 1901 Insu-

lar Cases, a series of opinions addressing the status of Puerto Rico,

the Philippines, and other overseas possessions, in which the Court

had held that the Constitution does not apply in all its force to

every territory under U.S. control.

700

While searches within the

United States fell subject to the Fourth Amendment, practical barri-

ers could prevent the same overseas.

701

Kennedy pointed to “[t]he

absence of local judges or magistrates available to issue warrants,

the differing and perhaps unascertainable conceptions of reasona-

bleness and privacy that prevail abroad, and the need to cooperate

with foreign officials” as reasons why “the warrant requirement

should not apply in Mexico as it does in this country.”

702

Justice Brennan, joined by Justice Marshall, dissented.

703

How

could the United States expand its extraterritorial criminal provi-

sions without correspondingly allowing the Fourth Amendment to

travel abroad? The fact that a foreign national was being investi-

gated for a violation of U.S. law, for which he could conceivably

“spend the rest of his life in a United States prison,” was sufficient

697. Verdugo-Urquidez, 494 U.S. at 271, 274–75. See also Reid v. Covert, 354 U.S.

1, 5–6 (1957) (plurality opinion) (stating that the “shield” that the Bill of Rights

provides “should not be stripped away just because [a U.S. citizen] happens to be

in another land”).

698. Verdugo-Urquidez, 494 U.S. at 262.

699. Id. at 271, 274–75.

700. Id. at 277 (Kennedy, J., concurring) (citing Downes v. Bidwell, 182 U.S.

244 (1901); Hawaii v. Mankichi, 190 U.S. 197 (1903); Dorr v. United States, 195

U.S. 138 (1904); Balzac v. Porto Rico, 258 U.S. 298 (1922)) (stating that the cases

“stand for the proposition that we must interpret constitutional protections in light

of the undoubted power of the United States to take actions to assert its legitimate

power and authority abroad”).

701. Verdugo-Urquidez, 494 U.S. at 278.

702. Id.

703. Id. at 279 (Brennan, J., dissenting).

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 667

to bring the Fourth Amendment to bear.

704

As soon as U.S. law

applied, the foreign national became, “quite literally, one of the

governed.”

705

Fundamental fairness required that if individuals

were obliged to comply with U.S. law, then the government, in turn,

was “obliged to respect certain correlative rights, among them the

Fourth Amendment.”

706

Under Verdugo-Urquidez, non-U.S. citizens based overseas, who

lack a significant connection to the country, do not enjoy the pro-

tections of the Fourth Amendment.

707

Lower court decisions ap-

pear to come down on different sides of what, precisely, constitutes

a “substantial connection.”

708

For U.S. citizens outside the country,

the Fourth Amendment does apply—albeit under different stan-

dards than those extended within the United States.

709

The Supreme Court has not spelled out precisely what is re-

quired, although some lower courts have considered this question.

In United States v. Barona, the Ninth Circuit determined that the

Fourth Amendment only applies insofar as the search in question

meets the reasonableness standard.

710

It does not demand that offi-

cials first obtain a warrant.

711

That case dealt with a DEA search

conducted at the apex of the so-called “war on drugs,”

1985–1987.

712

As the DEA had used electronic intercepts in accor-

dance with Danish law, the court looked to whether the search was

reasonable within the context of Denmark’s legal framework, as

704. Id. at 283–84.

705. Id. at 284.

706. Id.

707. For discussion of this point and how the courts have subsequently an-

swered the question of what constitutes a sufficient connection to the United

States, see Laura K. Donohue, Section 702 and the Collection of International Telephone

and Internet Content,

38(1) H

ARV

. J. L. & P

. P

’

(2015), http://scholar-

ship.law.georgetown.edu/facpub/1355/ [Hereinafter Donohue, Section 702].

708. Compare, e.g., Martinez-Aguero v. Gonzalez, 459 F.3d 618, 625 (5th Cir.

2006) (finding substantial connections on the grounds that “regular and lawful

entry . . . and [ ] acquiescence in the U.S. system of immigration constitute [ ]

voluntary acceptance of societal obligations”), with United States v. Esparza-Men-

doza, 265 F.Supp.2d 1254, 1271 (D. Utah 2003), aff’d, 386 F.3d 953 (10th Cir.

2004) (holding that “previously deported alien felons [who illegally re-enter the

country] are not covered” under the sufficient connections on the grounds that he

is “a trespasser in this country.”); see also Donohue, Section 702, supra note 708;

Orin S. Kerr, The Fourth Amendment and the Global Internet, 67

TAN

. L. R

. 285,

291–93 (2015).

709. See, e.g., United States v. Peterson, 812 F.2d 486, 490 (9th Cir. 1987).

710. 56 F.3d 1087 (9th Cir. 1995).

711. Id.

712. Id. at 1089–90. See also Donohue, Section 702, supra note 707, at 231-

232.

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668 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

well as whether U.S. officials had relied in good faith upon the for-

eign officials’ representations that the wiretapping complied with

Danish law.

713

B. Foreign Intelligence Collection

Verdugo-Urquidez and Barona addressed ordinary law enforce-

ment activity. For foreign intelligence collection, different stan-

dards apply, but they are still premised on a distinction between

domestic and international searches. As with many of the authori-

ties and cases addressed in this Article, the framing developed in a

post-Katz world that no longer reflects the realities of a digital age.

In footnote 23 of Katz, the Court went out of its way to note

that the decision did not reach national security cases.

714

Neverthe-

less, three justices took the opportunity to postulate what might be

the appropriate standard for foreign intelligence collection. Justice

White came down on the side of giving the Executive Branch more

leeway.

715

Justice Douglas, in contrast, with whom Justice Brennan

joined, distanced himself from White’s view, which he considered

“a wholly unwarranted green light for the Executive Branch to re-

sort to electronic eavesdropping without a warrant in cases which

the Executive Branch itself labels ‘national security’ matters.”

716

Douglas recognized the potential conflict of interest in having the

President or the Attorney General ultimately decide the limits of

713. Id. at 1094. See also Donohue, Section 702, supra note 707, at 232. The

Second Circuit also found that the search of U.S. citizens overseas is only subject to

the reasonableness requirement, and not the warrant clause. In re Terrorist Bomb-

ings of U.S. Embassies in East Africa, 552 F.3d 157, 171 (2d Cir. 2008). In In re

Terrorist Bombings, American intelligence agencies had identified five telephone

numbers used by individuals suspected of association with al Qaeda. Id. at 159

(citing United States v. Bin Laden, 126 F. Supp. 2d 264, 269 (S.D.N.Y. 2000). For a

year, they monitored the lines, including ones used by an American citizen, El-

Hage. In 1997, the Attorney General authorized intelligence officials to target El-

Hage, placing his telephone line in his home in Nairobi, as well as his cell phone,

under surveillance. U.S. officials later searched his home without a warrant. Id. at

160.

714. Katz v. United States, 389 U.S. 347, 358 n.23 (1967) (“Whether safe-

guards other than prior authorization by a magistrate would satisfy the Fourth

Amendment in a situation involving the national security is a question not

presented by this case.”).

715. Id. at 364 (White, J., concurring) (“We should not require the warrant

procedure and the magistrate’s judgment if the President of the United States or

his chief legal officer, the Attorney General, has considered the requirements of

national security and authorized electronic surveillance as reasonable.”); see also

Donohue, Section 702, supra note 708.

716. Katz, 389 U.S. at 359 (Douglas, J., concurring); Donohue, Section 702,

supra note 708.

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 669

their own powers.

717

The fact that the crimes in question were the

most serious that could be alleged did little to alter his calculus.

718

Congress responded to Katz by passing Title III of the Omni-

bus Crime Control and Safe Streets Act of 1968.

719

The legislation

originally covered just wire and oral communications, but in 1986

Congress expanded it to include electronic communications. The

Electronic Communications Privacy Act of 1986 included two addi-

tional titles focused on stored communications, as well as pen regis-

ter and trap and trace devices.

720

Title III exempted matters

involving national security:

Nothing contained in this chapter . . . shall limit the constitu-

tional power of the President to take such measures as he

deems necessary to protect the Nation against actual or poten-

tial attack or other hostile acts of a foreign power, to obtain

foreign intelligence information deemed essential to the secur-

ity of the United States, or to protect national security informa-

tion against foreign intelligence activities.

721

Congress was careful to draft the law in a way that left the Presi-

dent’s authority in the realm of foreign affairs intact.

722

Foreign in-

717. Katz, 389 U.S. at 359–60 (Douglas, J., concurring) (“Neither the Presi-

dent nor the Attorney General is a magistrate. In matters where they believe na-

tional security may be involved, they are not detached, disinterested, and neutral

as a court or magistrate must be. Under the separation of powers created by the

Constitution, the Executive Branch is not supposed to be neutral and disinter-

ested. Rather it should vigorously investigate and prevent breaches of national se-

curity and prosecute those who violate the pertinent federal laws. The President

and Attorney General are properly interested parties, cast in the role of adversary,

in national security cases. They may even be the intended victims of subversive

action.”).

718. Id. at 360 (“Since spies and saboteurs are as entitled to the protection of

the Fourth Amendment as suspected gamblers like petitioner, I cannot agree that,

where spies and saboteurs are involved adequate protection of Fourth Amendment

rights is assured when the President and Attorney General assume both the posi-

tion of ‘adversary and prosecutor’ and disinterested, neutral magistrate.”).

719. Omnibus Crime Control and Safe Streets Act of 1968, Pub. L. 90-351, 82

Stat. 197, codified at 42 U.S.C. § 3711.

720. Electronic Communications Privacy Act of 1986, Pub. L. No. 99-508, 100

Stat. 1848, 1860, 1868 (codified as amended 8 U.S.C. §§ 2701, 3121 (1986)).

721. Omnibus Crime Control and Safe Streets Act of 1968, Pub. L. No. 90-

351, 82 Stat. 197, 214 (1968).

722. 114 Cong. Rec. 14751 (1968) (Senators Holland, McClellan, and Hart

stating that the legislation neither expanded nor contracted the President’s for-

eign affairs powers); S. Rep. No. 90-1097, at 65 (1968) (stating that the power of

the president “is not to be deemed disturbed” by the legislation). See also Dono-

hue, Section 702, supra note 708, at 208.

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670 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

telligence collection would be subject to different standards.

Precisely what had yet to be decided.

In 1972, the Court weighed in on the question. In United States

v. United States District Court for the Eastern District of Michigan, the

Court suggested that in cases of domestic security, while some sort

of judicial process was required for domestic interception, the stan-

dard could differ from criminal law.

723

The government had con-

ducted a warrantless wiretap on three people suspected of bombing

a Central Intelligence Agency office.

724

The Court agreed 8-0 that

under the circumstances, the Government first had to obtain a war-

rant.

725

The Court cited the “inherent vagueness of the domestic

security concept” as well as the risk of government abuse of power

as reasons why the Fourth Amendment prevailed.

726

While the Gov-

ernment had to use what technological means it had at its disposal

to protect citizens, giving the Executive Branch carte blanche un-

dermined citizens’ rights.

727

Just as Justice Douglas in Katz had argued about the conflict of

interest that marked giving the Executive the latitude to set the con-

tours of its own power, Powell argued in Keith that, “Fourth Amend-

ment freedoms cannot properly be guaranteed if domestic security

surveillances may be conducted solely within the discretion of the

Executive Branch.”

728

Some sort of judicial process was neces-

sary.

729

The precise contours lay in the domain of the legislature.

“Different standards,” Powell wrote, “may be compatible with the

Fourth Amendment if they are reasonable both in relation to the

legitimate need of Government for intelligence information and

the protected rights of our citizens.”

730

In criminal law, probable

cause was the standard against which reasonableness was weighed;

for foreign intelligence, the probable cause requirements may re-

flect “other circumstances more appropriate to domestic security

723. 407 U.S. 297, 322 (1972) [hereinafter Keith]; see also Donohue, Section

702, supra note 708, at 209.

724. Keith, 407 U.S. at 299.

725. Id. at 298, 320.

726. Id. at 320; see also Donohue, Section 702, supra note 708.

727. Keith, 407 U.S. at 312; see also Donohue, Section 702, supra note 708.

728. Keith, 407 U.S. at 316–17; see also Donohue, Section 702, supra note 708, at

210.

729. Keith, 407 U.S. at 318; see also Donohue, Section 702, supra note 708, at

210.

730. Keith, 407 U.S. at 322–23; see also Donohue, Section 702, supra note 708, at

210.

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 671

cases.”

731

It may require a special court, different timing and report-

ing requirements than those outlined in Title III, and other special

considerations.

732

The 1978 Foreign Intelligence Surveillance Act (FISA) served

as Congress’s riposte.

733

The legislation was to be the only way the

Executive branch could engage in domestic electronic surveillance

for foreign intelligence purposes.

734

It later expanded FISA to gov-

ern physical searches, pen register and trap and trace devices, and

tangible goods.

735

For each of these areas, FISA incorporated standards more le-

nient than those that mark criminal law. Instead of requiring proba-

ble cause that a crime had been, was being, or was about to be

committed, for instance, before electronic surveillance could com-

mence, it required only probable cause that an individual was a for-

eign power or an agent of a foreign power, and probable cause that

they would use the facilities to be placed under surveillance, before

a special order from the FISC would issue.

736

The courts repeatedly

upheld FISA as compatible with the Fourth Amendment.

737

731. Keith, 407 U.S. at 323; see also Donohue, Section 702, supra note 708, at

210.

732. Keith, 407 U.S. at 323.

733. Foreign Intelligence Surveillance Act of 1978, Pub. L. 95-511, 92 Stat.

1783, codified at §§ 1801–1812, 1821–1829, 1841–1846.

734. See generally Donohue, Bulk Metadata, supra note 6, at 776–93 (discussing

the historical background, structure, and purpose of the FISA);

ONOHUE

, F

U-

TURE

, supra note 6

at 11.

735. Intelligence Authorization Act for Fiscal Year 1995, Pub L. No. 103-359,

§ 302(c), 108 Stat. 3423, 3445 (1994) (codified at 50 U.S.C. §§ 1821–1829) (physi-

cal searches); Intelligence Authorization Act for Fiscal Year 1999, Pub. L. No. 105-

272, § 601, 112 Stat. 2396, 2404–2410 (1998) (codified at 50 U.S.C. §§ 1841–1846)

(pen register and trap and trace devices); Id. § 602 (codified at 50 U.S.C

§§ 1861–1862); see also Uniting and Strengthening America by Providing Appropri-

ate Tools Required to Intercept and Obstruct Terrorism (USA PATRIOT Act),

Pub. L.107-56, U.S.C. § 1861, 115 Stat. at 287 (2001) (evolution of business records

to tangible goods).

736. Compare Omnibus Crime Control and Safe Streets Act of 1968, Pub. L.

No. 90-351, tit. III, § 802, 82 Stat. 212 (1968) (codified as amended at 18 U.S.C.

§§ 2510–22 (2012)), with 50 U.S.C. §1805(b).

737. See, e.g., United States v. Pelton, 835 F.2d 1067, 1074–76 (4th Cir. 1987),

cert denied, 486 U.S. 1010 (1988); United States v. Ott, 827 F.2d 473, 475 (9th Cir.

1987); United States v. Badia, 827 F.2d 1458, 1464 (11th Cir. 1987); United States

v. Truong Dinh Hung, 629 F.2d 908 (4th Cir. 1980); United States v. Abu-Jihaad,

531 F. Supp. 2d 299, 304 (D. Conn. 2008); United States v. Mubayyid, 521 F. Supp.

2d 125, 136 (D. Mass 2007); United States v. Megahey, 553 F.Supp. 1180, 1185–93

(E.D.N.Y.), aff’d, 729 F.2d 1444 (2d Cir. 1982), and aff’d sub nom United States v.

Duggan, 743 F.2d 59 (2d Cir. 1984).

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672 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

FISA stopped at the border of the United States. All foreign

intelligence surveillance involving electronic intercepts (and later,

physical searches, pen register and trap and trace, or tangible

goods), could only be undertaken on domestic soil consistent with

the requirements in the statute. Internationally, intelligence collec-

tion fell outside the statutory regime and stemmed from the Presi-

dent’s Article II authorities. From 1981 until 2008, such acquisitions

only had to comport with the guidelines laid out in Executive Or-

der 12,333.

738

In 2008, Congress passed the Foreign Intelligence

Surveillance Amendments Act (FAA), bringing electronic surveil-

lance of U.S. persons overseas within the contours of FISA.

739

Prior to enactment of the FAA, the Southern District of New

York (S.D.N.Y.) considered in a counter-terrorism context whether

a U.S. citizen placed under surveillance overseas was entitled to the

full protections of the Fourth Amendment and determined that he

was not.

740

In United States v. Bin Laden, the Court rejected the ne-

cessity of law enforcement first obtaining a warrant before placing

either a landline or a mobile telephone under surveillance.

741

The

Court concluded that because of the undue burden that it would

place on the Executive Branch, foreign intelligence collection over-

seas fell into the “special needs” exception.

742

Because of the “intri-

cacies” involved, courts were “ill-suited to the task of overseeing

foreign intelligence collection.”

743

It was difficult to predict the in-

ternational consequences of wiretapping on foreign soil; other

countries might not want to be seen as complicit with actions taken

by the United States, and enemies might be alerted to investigations

underway—not least by foreign officials sympathetic to their

cause.

744

The potential for security breaches to occur was

significant.

745

738. See Exec. Order No. 12,333, 3 C.F.R. 200 (1981), reprinted in 50 U.S.C.

§ 401 app. at 44–51 (1982); see also Donohue, Section 702, supra note 708;

ONO-

HUE

, F

UTURE

, supra note 6

at 12

739. FISA Amendments Act of 2008, 50 U.S.C. § 1181(b) (2008); see also Pro-

tect America Act of 2007, Pub. L. No. 110-55, 121 Stat. 552 (temporarily bringing

the collection of foreign intelligence targeting U.S. persons within the bounds of

FISA); Donohue, Section 702, supra note 708.

740. See Bin Laden, 126 F. Supp. 2d at 264. See Donohue, Section 702, supra

note 708.

741. Bin Laden, F. Supp. 2d at 275–76.

742. Id. at 274. See also Donohue, Section 702, supra note 707, at 233.

743. Bin Laden, F. Supp. 2d at 274.

744. Id. at 275. See also Donohue, Section 702, supra note 708.

745. Bin Laden, F. Supp. 2d at 275.

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The S.D.N.Y. was careful to note the absence of any legislative

framing.

746

The political branches, which were responsible for for-

eign affairs, had yet to create a warrant requirement for collection

of intelligence abroad, making any judicial effort to do so some-

what suspect.

747

It was therefore up to the other two branches to

work out the extent to which a warrant would be required and the

specific procedures that would have to be followed for overseas col-

lection. Deference, however, extended only insofar as collection

centered on foreign intelligence.

748

As soon as the primary purpose

of the search shifted to criminal law, ordinary Fourth Amendment

standards for searches conducted overseas applied.

749

In 2008, the Foreign Intelligence Surveillance Court of Review

(FISCR) also considered whether a foreign intelligence exception

to the warrant requirement existed for intelligence collected

abroad.

750

FISCR pointed to its earlier opinion, which had assumed

that regardless of whether a foreign intelligence exception to the

warrant requirement existed, FISA met the Fourth Amendment

standard of reasonableness.

751

It then turned to the question of

whether, by a special needs analogy, there was a foreign intelligence

exception to the warrant requirement.

FISCR emphasized the exceptional nature of national security,

stating that the purpose behind foreign intelligence collection

“goes well beyond any garden-variety law enforcement objective. It

involves the acquisition from overseas foreign agents of foreign in-

telligence to help protect national security.”

752

The court neverthe-

less rejected the proposition that the primary purpose of the

investigation had to be related to foreign intelligence for the spe-

cial needs exception to apply:

[I]n our view the more appropriate consideration is the

programmatic purpose of the surveillances and whether – as in

746. Bin Laden, F. Supp. 2d at 275–77. See also Donohue, Section 702, supra

note 708, at 233-234.

747. Bin Laden, F. Supp. 2d at 275–77.

748. Id. at 277.

749. Id. See also Donohue, Section 702, supra note 708, at 234.

750. In re Directives Pursuant to Section 105B of the Foreign Intelligence Sur-

veillance Act, 551 F.3d 1004 , 1012 (FISA Ct. Rev. Aug. 22, 2008); see also Donohue,

Section 702, supra note 708, at 234-235.

751. In re Directives, 551 F.3d at 1011; In re Sealed Case, 310 F.3d 717, 744

(FISA Ct. Rev. 2002). See also Donohue, Section 702, supra note 708, at 235.

752. In re Directives, 551 F.3d at 1011. See also Donohue, Section 702, supra note

708, at 235.

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674 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

the special needs cases – that programmatic purpose involves

some legitimate objective beyond ordinary crime control.

753

Forcing the government to obtain a warrant would hurt its abil-

ity “to collect time-sensitive information and, thus, would impede

the vital national security interests that are at stake.”

754

For foreign

intelligence collection, then, a different standard marks searches

conducted overseas than those within domestic bounds.

The problem, as with criminal law, is that the distinction be-

tween domestic and international communications breaks down in

light of new technologies.

755

C. Technological Challenges to the Domestic/International Distinction

Global communications are, well, just that: global. They do not

recognize terrestrial borders. Why conform Fourth Amendment re-

quirements to geographic borders, when packets of information

freely flow across them, and, for the most part, outside the control

of users? The same information that would be protected under one

framing falls subject to lesser protections under the other, despite

the fact that the same communications are at stake—making Consti-

tutional rights not so dependent on actual privacy needs, but on an

accident of how the Internet works at any given time.

Consider, for instance, electronic mail communications. If I e-

mail a colleague in the office next to mine, it may—or may not—be

routed to a server in Singapore, where it awaits retrieval. Pari passu,

foreign to foreign communications may be brought within the

United States simply by being sent by the Internet across a U.S.

frontier. In days of old, when telephone communications were car-

ried on wires draped across land and water, one could intercept

conversations entirely outside U.S. borders. But today, one scholar

sitting in Dublin could e-mail a colleague in Bonn. And just as my e-

753. In re Directives, 551 F.3d at 1011. See also Donohue, Section 702, supra note

708, at 236.

754. In re Directives, 551 F.3d at 1011. See also Donohue, Section 702, supra note

708, at 237.

755. Although I focus on the physical characteristics (or lack thereof) of digi-

tal technologies, commentators also have focused on other ways in which technol-

ogy has undermined Fourth Amendment doctrine as applied to searches outside

the United States. See, e.g., Street, supra note 688, at 429 n.72 (arguing that in the

21st century, “technology and the pervasive transnational terrorist threat have

broadened the scope of the international silver platter doctrine, reduced the im-

pact of its joint venture exception, and consequently rendered the Fourth Amend-

ment, in practice, virtually inapplicable to most transnational terrorism

investigations.” The result is that more evidence obtained in unreasonable

searches can be used in U.S. federal court.).

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 675

mail to a domestic colleague could go to Singapore, the e-mail from

Dublin may be routed through Palo Alto, California. Does that

mean that those communications now fall subject to higher levels

of protection—either in the criminal law realm or in the foreign

intelligence arena?

In 2008, Congress addressed the second part of the concern by

enacting the FAA.

756

The government argued against extending

higher Fourth Amendment protections to non-U.S. persons abroad

simply because they chose to use a U.S. Internet service provider.

757

It was a sound argument. For one, it made little sense to have con-

stitutional protections rest on the particular ISP involved, and not

the status of the individual or the nature of the communication at

stake. For another, if by simply using an American ISP, a foreign

terrorist could gain greater protections, it would allow individuals

to game U.S. law to evade detection.

758

The problem that global communications present to Fourth

Amendment law, however, works both ways. Even as communica-

tions overseas might be routed through the U.S., entirely domestic

communications might now be routed overseas. If I email or text

my colleague at Georgetown, the message may be routed through a

server in Singapore before my colleague receives it. Through no

action of my own, an entirely domestic message has traveled

abroad. Yet it may be precisely the same message that, historically, if

sent through regular mail, would have received full Fourth Amend-

ment protections. So drawing a line at the border of the country,

and extending fewer protections to the international communica-

tions, results in greater surveillance of U.S. citizens than has tradi-

tionally occurred.

759

The intense controversy surrounding Section

756. Foreign Intelligence Surveillance Act of 1978 Amendments Act of 2008,

Pub. L. 110-261, 122 Stat. 2436, July 10, 2008; see also Donohue, Section 702, supra

note 708;

ONOHUE

, F

UTURE

, supra note 6

at 33.

757. Open/Closed Hearing: FISA Before the S. Select Comm. on Intelligence, 110th

Cong. (2007) (statement of John M. McConnell, Director of National Intelli-

gence); see also 154

ONG

. R

. H5756–57

(daily ed. June 20, 2008)

(

letter from

Michael Mukasey, Attorney General, and J.M. McConnell, Director of National In-

telligence, to Hon. Nancy Pelosi, Speaker, House of Representatives (June 19,

2008)); 154

ONG

. R

. S6400–01

(July 8, 2008) (letter from Michael Mukasey,

Attorney General, and J.M. McConnell, Director of National Intelligence, to Hon.

Harry Reid, Majority Leader, Senate (July 7, 2008)); Donohue, Section 702, supra

note 708.

758. See also Donohue, Section 702, supra note 708 (arguing that this was the

strongest point put forward by the government in support of the FAA).

759. For discussion of this point, see Donohue, Section 702, supra note 708; see

also Spencer Ackerman, FBI Quietly Changes its Privacy Rules for Accessing NSA Data

on Americans,

UARDIAN

(Mar. 8, 2016) (reporting PCLOB’s confirmation that

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676 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

702 of the FISA Amendments Act centered in no small measure on

the government’s inability to actually calculate the number of

Americans whose privacy interests had been compromised even

through upstream collection, directed at non-U.S. citizens abroad,

and subsequent query of the database.

760

It is more than just communications data at stake. Cloud com-

puting, for instance, has altered where documents are not just

stored but also analyzed.

761

There are increasingly difficult ques-

tions that center on whether and under what conditions the U.S.

government can demand access to information held outside the

United States. The Second Circuit confronted this question in re-

gard to information linked to a Microsoft user’s web-based e-mail

account located in a data center in Dublin, Ireland.

762

A District

Court determined that because the information could be obtained

from Microsoft employees inside the United States, the warrant was

not extraterritorial and thus valid.

763

The Second Circuit Court of

Appeals, however, overruled this decision, stating that “to require a

service provider to retrieve material from beyond the borders of the

United States—would require us to disregard the presumption

against extraterritoriality that the Supreme Court emphasized in

“the FBI is allowed direct access to the NSA’s massive collections of international

emails, texts and phone calls – which often include Americans on one end of the

conversation”); see generally

ONOHUE

, F

UTURE

, supra note 6.

760. See, e.g.,

RIVATE

& C

IVIL

IBERTIES

VERSIGHT

. R

EPORT ON THE

UR-

VEILLANCE

ROGRAM

PERATED

URSUANT TO

ECTION

702

OF THE

OREIGN

NTELLI-

GENCE

URVEILLANCE

147 (2014) (“[L]awmakers and the public do not have

even a rough estimate of how many communications of U.S. persons are acquired

under Section 702.”); James Ball & Spencer Ackerman, NSA Loophole Allows War-

rantless Search for U.S. Citizens’ E-mails and Phone Calls,

UARDIAN

(Aug. 9,

2013), http://www.theguardian.com/world/2013/aug/09/nsa-loophole-warrant-

less-searches-email-calls; Elizabeth Goitein, The NSA’s Backdoor Search Loophole,

RENNAN

ENTER FOR

USTICE

(Nov. 14, 2013), https://www.brennancenter.org/

analysis/nsas-backdoor-search-loophole; Civil Society to FBI: Show Us How Section 702

Affects Americans,

ROJECT ON

OVERNMENT

VERSIGHT

(

Oct. 29, 2015), http://

www.pogo.org/our-work/letters/2015/civil-society-to-fbi-show-us.html.

761. See Jessica Scarpati, Big Data Analysis in the Cloud: Storage, Network and

Server Challenges,

ECH

ARGET

, http://searchtelecom.techtarget.com/feature/Big-

data-analysis-in-the-cloud-Storage-network-and-server-challenges (discussing the

challenges of big data analytics in the cloud, including whether to move petabytes

of data, as opposed to moving analytics to the data, to most effectively provide

cloud-based services).

762. In re Warrant to Search a Certain E-mail Account Controlled and Main-

tained by Microsoft Corp., 15 F. Supp. 3d 466 (S.D.N.Y. 2014).

763. Microsoft, 15 F. Supp. 3d at 476; see also Jennifer Daskal, The Un-Territorial-

ity of Data, 125

ALE

L. J.

326 (2016).

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 677

Morrison v. Nat’l Austl. Bank Ltd., 561 U.S. 247 (2010).”

764

As Profes-

sor Jennifer Daskal, who has written thoughtfully about digital

(un)territoriality, observed, “The dispute lays bare the extent to

which modern technology challenges basic assumptions about what

is ‘here’ and ‘there.’”

765

The problem with Fourth Amendment jurisprudence is that it

assumes that one can draw a line at the border, and that the draw-

ing of this line can be used in some meaningful way to determine

the extent of constitutional protections. But, as Daskal notes, two

aspects of the digital world make this impossible: first, data flows

across borders at the speed of light and in unpredictable ways. Sec-

ond, there is no necessary connection between where the data is

located and where the individual that either “owns” the data, or to

whom the data relates, is located, undermining the significance of

where the data is at any moment in time.

766

Whether the individual

to whom the data relates is a U.S. person, or a non-U.S. person

lacking a significant connection to the United States (as framed in

Verdugo-Urquidez), may be impossible to ascertain. No clearer is such

a connection between bits and bytes flowing over the Internet and

the citizenship or location of the foreign power at issue in FISA—

even as amended.

Even if one had the IP address of a particular user, it is not at

all clear from that information where a user is located—or even

whether it is accurate. IP addresses are numerical sequences that

can identify specific computers when they go online. They are used

to route information to and from websites. But web anonymizers

can hide IP addresses by creating a proxy, contacting the website on

your behalf and forwarding the relevant information to you, so that

no direct connection between your computer and the website is

ever formed.

767

With global communications, and the lack of digital technolo-

gies’ territorial tie in mind, the concern is that the end result will be

one in which the weaker standards previously adopted in regard to

information obtained outside the United States become applied to

an increasing amount of citizens’ private data that happens to ei-

ther flow across international borders, or to be held in foreign

countries. This is the de facto standard already applied to foreign

764. Microsoft Corp. v. United States (In re Warrant to Search a Certain E-

mail Account Controlled and Maintained by Microsoft Corp.), 829 F.3d 97, 201

(2d Cir. 2016).

765. The Un-Territoriality of Data, supra note 764.

766. Id.

767. See e.g.,

NONYMIZER

, http://www.webanonymizer.org.

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678 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

intelligence collection and raises concerns about how the informa-

tion is being used in a criminal law context—to say nothing about

how the courts should consider criminal investigations when inter-

national data is involved.

VII.

CONFRONTING THE DIGITAL WORLD

The time is ripe to revisit the post-Katz distinctions—private vs.

public; personal information vs. third party data; content vs. non-

content; and domestic vs. international. They fail to capture the pri-

vacy interests affected by the digital sphere.

As this Article has argued, the ubiquitous nature of tracking

technologies undermines the claim that what one does in public

does not generate insight into private lives. Similarly, the rule that

individuals lose their right to protect data when it is entrusted to

others ignores the extent to which, as a society, we have become

dependent on commercial entities to conduct our daily lives. If all

information entrusted to third parties loses its constitutional pro-

tections, then the right to privacy itself will gradually cease to exist.

Individuals cannot live in the modern world without creating a digi-

tal doppelganger that yields insight into our most intimate affairs.

Denying the substantive interests involved in e-mail, texting, instant

messages, and other forms of communication, moreover, subverts

the purpose of distinguishing between content and non-content—

even as technology has transmuted traditional areas of non-content

to content. Global communications and cloud computing, in turn,

collapse the line between what occurs inside the United States and

that which transpires abroad.

The Court’s continued reliance on these distinctions is leading

to a narrowing of rights, with detrimental consequences for individ-

ual liberty.

There are a number of possible responses that the Court could

make to the current situation in which we find ourselves. Prior to

Katz, for instance, judicial doctrine reflected a textual approach,

protecting “houses” and “papers” from the intrusive eyes of the

government.

Accordingly, some scholars have suggested that digital informa-

tion similarly should be considered “papers” and within the protec-

tion of the home, such that the type of information that would have

been located behind closed doors falls within the ambit of the

Fourth Amendment. The analogy runs: in a digital world, we no

longer keep our papers in the den. Instead, we place them on the

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 679

cloud, encrypted. Whether the data is physical or digital should

have little bearing on whether or not it is considered private. Either

way, it is the same information in question.

A parallel approach centers on whether digital data ought to

be considered within the domain of “effects.”

768

As Professor Mau-

reen Brady points out, compared to “houses” and “papers,” “effects”

has captured rather less of the Supreme Court’s attention.

769

When

it has, property considerations loom large.

770

In crafting a deeper

understanding, Brady proposes that the Court look to the context,

considering whether the subject of the inquiry is personal property,

and whether the individual in question retains possession over it,

rendering the property “presumptively entitled to Fourth Amend-

ment protection.”

771

This means looking beyond the actual location

of the item—be it in a filing cabinet or on the cloud—and consid-

ering, instead, the nature of the item, its relationship to other

items, and whether the owner has taken steps to shield the informa-

tion from public scrutiny.

772

A similar response centers on the Court’s understanding of

“persons.” Much has been written about the “digital self”—dopple-

gangers that exist as a byproduct of living in the modern world.

773

As an extension of personhood, the digital self provides insight into

one’s intimate sphere. Under this approach, the collection of

uniquely identifiable information, i.e., data that relates, and could

be traced back, to unique individuals, may constitute a search per

se, requiring a warrant for collection.

768. See Bagley, supra note 534, at 158 (looking at “the evolution of papers

and effects increasingly stored by third party Internet giants”).

769. Maureen E. Brady, The Lost “Effects” of the Fourth Amendment: Giving Per-

sonal Property Due Protection, 125

ALE

L. J. 946, 980

(2016).

770. Id. at 981.

771. Id. at 951.

772. Id. at 952.

773. See, e.g.,

OLOVE

supra note 3

;

Jeremy N. Bailenson, Doppelgangers: A New

Form of Self, 25

SYCHOLOGIST

36, 36–39 (2012); Russell W. Belk, Extended Self in

a Digital World,

J. C

ONSUMER

ESEARCH

477–500 (Oct. 2013); Hope Jensen Schau &

Mary C. Gilly, We Are What We Post? Self-presentation in Personal Web Space, 30

J. C

ON-

SUMER

ESEARCH

385 (2003); Nick Yee et al., The Expression of Personality in Virtual

Worlds, 2

. P

SYCHOL

. & P

ERSONALITY

5, 5–12 (2011); Nick Yee & Jeremy N.

Bailenson, The Difference Between Being and Seeing: The Relative Contribution of Self-

Perception and Priming to Behavioral Changes via Digital Self-Representation, 12

EDIA

SYCHOLOGY

195 (2012); Nick Yee et al., The Proteus Effect: Implications of Transformed

Digital Self-Representation on Online and Offline Behavior, 33

OMMUNICATION

E-

271 (2009); Shanyang Zhao, The Digital Self: Through the Looking Glass of

Telecopresent Others, 28

YMBOLIC

NTERACTION

387 (Aug. 2005).

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680 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

The problem with these approaches is twofold: first, they do

not directly confront the problems raised by the Katz reasonable-

ness standard, discussed, at length, above. Second, more pro-

foundly, they neither confront the theoretical framing of the

Fourth Amendment, which presupposes a pre-political self, nor do

they question the contemporary assumption that the purpose of the

Fourth Amendment is to protect privacy.

In 2013, Professor Julie Cohen attacked the concept of a lib-

eral self.

774

She argued that the real object of privacy law is a so-

cially-constructed being, “emerging gradually from a preexisting

cultural and relational substrate.”

775

For Cohen, liberal political

theory’s commitment to definitions of absolute rights and core

principles is the problem. It fails to acknowledge the types of pri-

vacy expectations that mark the real world.

776

“The self,” Cohen

writes, “has no autonomous, precultural core, nor could it, because

we are born and remain situated within social and cultural con-

texts.”

777

Pari passu, “privacy is not a fixed condition, nor could it

be, because the individual’s relationship to social and cultural con-

texts is dynamic.”

778

Cohen’s insight illuminates Professor Anita Allen’s observation

that society’s expectation of privacy appears to be changing.

779

“Neither individuals, institutions, nor government consistently de-

mand or respect physical, informational, and proprietary privacy,”

Allen writes.

780

Thus, while polling data may show high levels of

concern about privacy, “Certain legal and policy trends; certain

modes of market, consumer, and political behavior; and certain

dimensions of popular culture . . . suggest low levels of concern.”

781

Allen cites to the “avalanche of technologies” that make informa-

tion available to industry and the government.

782

She concludes,

“Liberals may need to rethink the claims they have always made

about the value of privacy.”

783

Cohen’s approach offers a way out of Allen’s conundrum. In-

stead of beginning from the point of political theory or philosophy,

774. Julie Cohen, What Privacy Is For, 126

ARV

. L. R

1904 (2013).

775. Id. at 1905.

776. Id. at 1907.

777. Id. at 1908.

778. Id.

779. Anita L. Allen, Coercing Privacy, 40

. & M

ARY

L. R

723, 727–28

(1999).

780. Id. at 728.

781. Id. at 729.

782. Id. at 730.

783. Id. at 728.

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2017] THE FOURTH AMENDMENT IN A DIGITAL WORLD 681

Cohen proposes that one must look to cognitive science, sociology,

and social psychology to find the empirical foundations for under-

standing socially-constructed subjectivity.

784

In this framing, privacy

plays a critical role, incubating subjectivity and independence, and

wrenching individuals and communities from the clutches of gov-

ernments and commercial actors that would relegate them to fixed,

transparent, and predictable beings.

785

Perceived in this way, pri-

vacy “protects the situated practices of boundary management

through which the capacity for self-determination develops.”

786

The

problem with a digitized, networked world, as it is currently con-

structed, is that it allows constant access to the boundary and there-

fore prevents the evolution of the socially-constructed self, outside

of external influence.

787

Cohen’s conception of social construction as a theory of sub-

jectivity differs in subtle but important way from other scholars who

see privacy as socially constructed.

788

Professors Joshua Fairfield

and Christoph Engel, for instance, try to turn the lens away from

individuals in measuring harm. Instead, they draw attention to the

negative externalities on non-consenting outsiders that are caused

by the revelation of personal data.

789

Eschewing individualism, they

argue, “it makes sense to examine privacy as a social construct, sub-

ject to the problems of social production.”

790

They continue, “with-

out measured intervention, individuals’ fully informed privacy

784. Cohen, supra note 774, at 1908.

785. Id. at 1905.

786. Id.

787. Id. at 1916. (“In the contemporary information economy, private-sector

firms like Google, Facebook, and data broker Acxiom use flows of information

about consumer behavior to target advertisements, search results, and other con-

tent. . . . Information from and about consumers feeds into sophisticated systems

of predictive analytics so that surveillant attention can be personalized more pre-

cisely and seamlessly. Government is an important secondary beneficiary of infor-

mational capitalism, routinely accessing and using flows of behavioral and

communications data for its own purposes. . . . In the modulated society, surveil-

lance is not heavy-handed; it is ordinary, and its ordinariness lends it extraordinary

power.”).

788. Professor Valerie Steeves highlights privacy as a social value, emphasizing

its role in identity, dignity, autonomy, social freedom, and democracy. She consid-

ers the relationship between privacy and social equality, with particular emphasis

on online social behavior. See, e.g., Ian Kerr & Valerie Steeves, Virtual Playgrounds

and Buddybots: A Data-Minefield for Tinys and Tweeneys,

ANOPTICON

, C

OMPUTERS

REEDOM AND

RIVACY

ONFERENCE

(Apr. 12, 2005), http://idtrail.org/content/

view/128/42/index.html.

789. Joshua A.T. Fairfield & Christoph Engel, Privacy as a Public Good, 65

UKE

L. J.

385 (2015).

790. Id. at 423.

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682 NYU ANNUAL SURVEY OF AMERICAN LAW [Vol. 71:553

decisions tend to reduce overall privacy, even if everyone cherishes

privacy equally and intensely.”

791

Applying a law and economics

model, the scholars map the social and systemic harms that result

from “the collection, aggregation, and exploitation of data.”

792

Un-

like Courts, which “tend to focus on specific harm to specific com-

plaining individuals, not undivided losses to social welfare,”

economists conceive of harm differently.

793

A critical question is

whether group harms “can be sufficiently theorized to be legally

cognizable.”

794

If the approach to the liberal self that is built into Fourth

Amendment doctrine is at least assailable, the object of the amend-

ment is even more vulnerable to question, with profound implica-

tions for evolution of the doctrine.

Specifically, some scholars argue that the underlying value of

the Fourth Amendment rests not on the right to privacy (either a

liberal incarnation or one premised on social construction), but on

liberty from undue government power.

795

Looked at in light of the his-

tory of the Fourth Amendment at the time of the Founding, this

approach is extremely persuasive.

796

There is little question that

Coke, Hale, and Hawkins, and other prominent English jurists and

Parliamentarians, worried about limiting the power of the

Crown.

797

It was to avoid the assumption and concentration of

power that the common law came to restrict powers of search and

seizure.

798

To place a limit on such powers, outside of hot pursuit of

a known felon, the Crown could not enter into any home without a

791. Id.

792. Id.

793. Id. at 425.

794. Id. Other scholars similarly consider group privacy. See, e.g.,

ROUP

RI-

VACY

: N

HALLENGES OF

ATA

ECHNOLOGIES

(

Luciano Floridi, Linnet Taylor &

Blair van der Sloot, eds

. 2017).

These theories, much like those posited by the

Court in Katz, recognize that some aspect of privacy is socially constructed.

795. See, e.g.,

ANIEL

OLOVE

, N

OTHING TO

IDE

: T

ALSE

RADEOFF

E-

TWEEN

RIVACY AND

ECURITY

, 1154 (Yale Univ. Press 2011) (focusing on the risks of

government collection of information and centering the analysis on the type and

extent of judicial oversight, limits on government actions, and guarding against

abuse of power); Thomas Clancy, What Does the Fourth Amendment Protect: Property,

Privacy, or Security?, 33

AKE

OREST

L. R

307, 351 (1998); Morgan Cloud, The

Fourth Amendment During the Lochner Era: Privacy, Property, and Liberty in Constitu-

tional Theory, 48

TAN

. L. R

. 555, 618–19 (1996) (arguing that the Fourth

Amendment “exists to enhance individual liberty by constraining government

power”).

796. See Donohue, Original, supra note 14.

797. Id.

798. Id.

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warrant.

799

Neither a general warrant, nor one lacking the requisite

particularity, would suffice.

800

The common law standard, of great

importance to the founding generation, became codified in the

U.S. Constitution.

In light of this history, it is perhaps unsurprising that in 2008,

Professor Jed Rubenfeld observed an “oddity” in the Fourth

Amendment: that privacy, “the ‘touchstone’ of modern Fourth

Amendment law[,] fails to touch one of the paradigmatic abuses—

arrests lacking probable cause made under a general warrant—that

the Fourth Amendment was enacted to forbid.”

801

The doctrine

should simply give up “trying to protect privacy.”

802

Instead, it

should turn to what the real purpose was behind the amendment,

which is a right of security.

803

Rubenfeld’s approach turns a cold shoulder to privacy as the

determinant of Fourth Amendment protections. Other scholars

take a similar line but are not quite as willing to throw the prover-

bial baby out with the bath water. Professor Paul Ohm, for instance,

has argued that just as privacy replaced property, the Court should

now consider power as the “constitutional lodestar” of the Fourth

Amendment.

804

It is not that privacy is irrelevant to the Fourth

Amendment enterprise—but rather that power ought to become a

new interpretative lens for giving substance to privacy

guarantees.

805

Ohm is right to the extent that power ought to be considered

the constitutional lodestar of the Fourth Amendment. But he is

wrong in suggesting that it is a new interpretive lens. It is, instead, a

return to the original values of the Fourth Amendment. And it of-

fers a promising way forward for the Court to confront the signifi-

cant threats posed by digitization, which carries with it the ability to

record vast amounts of information, to combine information to

799. Id.

800. Id.

801. Jed Rubenfeld, The End of Privacy, 61

TAN

. L. R

101, 104 (2008); see

also Donohue, Original, supra note 14, at 1188–93 (discussing the original prohibi-

tion on general warrants).

802. Rubenfeld, supra note 802, at 104.

803. Id. at 104–05.

804. Ohm, supra note 456, at 1338.

805. Various efforts have been made to put alternative approaches into prac-

tice. See generally, e.g., Kerr, supra note 35 (arguing that the rules ought to create a

level playing field between criminals and law enforcement in light of technological

advancement); Ohm, supra note 796 (building on Kerr by considering dual-assis-

tance technologies that help both law breakers and law enforcement).

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generate new knowledge, and to do so for many people over exten-

sive periods of time, with minimal resource constraints.

In Riley, the Court alluded to these concerns.

806

It acknowl-

edged four consequences that flowed from the government’s col-

lection of data, which helped to clarify why the search of a mobile

phone was more invasive than finding a packet of cigarettes in

someone’s pocket. The former had “several interrelated privacy

consequences.”

807

First, a cell phone collects in one place many distinct types of

information that reveal much more in combination than any

isolated record. Second, the phone’s capacity allows even just

one type of information to convey far more than previously

possible. Third, data on the phone can date back for years. In

addition, an element of pervasiveness characterizes cell phones

but not physical records. A decade ago officers might have oc-

casionally stumbled across a highly personal item such as a di-

ary, but today many in the more than 90% of American adults

who own cell phones keep on their person a digital record of

nearly every aspect of their lives.

808

Similar issues haunted the shadow majority in Jones. Justice Al-

ito recognized, “longer term GPS monitoring in investigation of

most offenses impinges on expectation of privacy.”

809

Justice Sotomayor explained, “In cases involving even short-

term monitoring, some unique attributes of GPS surveillance rele-

vant to the Katz analysis will require particular attention.”

810

That it

was precise and reflected a “wealth of detail about” one’s “familial,

political, professional, religious, and sexual associations,” was

relevant.

811

Sotomayor went on to note that the length of time the records

could be kept, and mined, for more information, raised further

concerns: “And because GPS monitoring is cheap in comparison to

conventional surveillance techniques and, by design, proceeds sur-

806. See also Susan Friewald, A First Principles Approach to Communications’ Pri-

vacy,

TAN

. T

ECH

. L. R

. (

2007) (arguing electronic surveillance that is intrusive

continuous, indiscriminate, and hidden should be subject to Fourth Amendment

restrictions). Friewald’s principles align with the direction the Court took in Riley

and Jones.

807. Riley, 134 S. Ct. at 2478.

808. Id.

809. United States v. Jones, 132 S. Ct. 945, 964 (2012) (Alito, J., concurring in

the judgment).

810. Id. at 955 (Sotomayor, J., concurring).

811. Id.

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reptitiously, it evades the ordinary checks that constrain abusive law

enforcement practices.”

812

Justice Sotomayor tried to fold her broader concerns into the

Katz framework: “I would ask whether people reasonably expect

that their movements will be recorded and aggregated in a manner

that enables the Government to ascertain, more or less at will, their

political and religious beliefs, sexual habits, and so on.”

813

But in

relying on Katz, Sotomayor’s approach fell short of challenging the

dichotomies and bringing attention to the underlying issue, which

is the steady expansion of government power over the people. By

acknowledging that the purpose of the Fourth Amendment was to

protect against the accumulation of power, the Court will be better

equipped to confront the dangers of the digital age.

812. Id. at 956.

813. Id.

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