Amicus Curiae Brief — George Anibowei, Petitioner v. Todd Blanche, Attorney General, et al.

No. 26-208

IN THE

GEORGE ANIBOWEI,

v.

Petitioner,

TODD BLANCHE, U.S. ATTORNEY GENERAL, et al.,

Respondents.

On Petition For A Writ Of Certiorari

To The United States Court Of Appeals

for the Fifth Circuit

BRIEF OF AMICUS CURIAE PROFESSOR

MORGAN CLOUD IN SUPPORT OF

PETITIONER

Alexander N. Ely

Counsel of Record

O’MELVENY & MYERS LLP

1625 I Street, NW

Washington, DC 20006

(202) 383-5370

aely@omm.com

Mark A. Racanelli

Brian Mucyo

O’MELVENY & MYERS LLP

1301 Avenue Of The Americas,

Fl. 17

New York, NY 10019

Skyanne Simonson

O’MELVENY & MYERS LLP

2801 N Harwood St. Ste. 1600

Dallas, TX 75201

i

TABLE OF CONTENTS

Page(s)

INTEREST OF AMICUS CURIAE ............................1

SUMMARY OF ARGUMENT.....................................1

ARGUMENT ...............................................................2

I. Introduction ........................................................2

II. Both Property and Privacy Rules Require a

Warrant Based on Probable Cause for

Searches of the Contents of Expressive

Property ............................................................5

A. The Fourth Amendment Text and the

Contents of Papers .....................................5

B. The Fourth Amendment Protects Both

Property and Privacy Rights .....................6

C. The Meaning of Property at the Founding .8

1. John Locke’s Theory of

Property ............................... 8

2. James Madison’s Broad

Theory of Property............. 10

III. Protections for the Contents of Papers .........12

A. British Paper Searches on the Eve of the

Revolution ................................................12

B. Early Supreme Court Decisions Protecting

the Contents of Papers Under the Fourth

Amendment ..............................................15

1. Ex Parte Jackson .................. 15

2. Boyd v. United States ........... 16

ii

TABLE OF CONTENTS

(continued)

Page(s)

IV. Requiring a Warrant to Search Cell Phone

Contents Is Consistent with Customs Laws

Dating Back to the First Congress ................17

CONCLUSION ..........................................................21

iii

TABLE OF AUTHORITIES

Page(s)

CASES

Beardmore v. Carrington,

(1764) 95 Eng. Rep. 790 ....................................... 13

Boyd v. United States,

116 U.S. 616 (1886) .........................7, 12, 16, 17, 19

Brower v. County of Inyo,

489 U.S. 593 (1989) .............................................. 12

Carpenter v. United States,

585 U.S. 296 (2018) ............................................ 3, 8

Chatrie v. United States,

146 S.Ct. 2193 (2026) ..................................... 3, 5, 7

Entick v. Carrington,

19 How. St. Tr. 1029 (C. P. 1765) .................. 13, 14

Entick v. Carrington,

95 Eng. Rep. 807 (C. P. 1765) .............................. 12

Ex Parte Jackson,

96 U.S. 727 (1878) .......................................... 15, 16

Florida v. Jardines,

569 U. S. 1 (2013) ................................................... 7

Huckle v. Money,

(1763) 95 Eng. Rep. 768 ....................................... 13

Katz v. United States,

389 U.S. 347 (1967) ................................................ 7

Kyllo v. United States,

533 U.S. 27 (2001) .................................................. 8

iv

TABLE OF AUTHORITIES

(continued)

Page(s)

LeClair v. Hart,

800 F.2d 692 (7th Cir. 1986) .................................. 3

Money v. Leach,

(1765) 97 Eng. Rep. 1075 ..................................... 13

Riley v. California,

573 U.S. 373 (2014) .......................2, 3, 4, 13, 15, 21

Soldal v. Cook County,

506 U.S. 56 (1992) .............................................. 7, 8

Terrence Byrd v. United States,

584 U. S. 395 (2018) ............................................... 7

United States v. Ackerman,

831F.3d 1292 (10th Cir. 2016) ............................... 3

United States v. Cotterman,

709 F.3d 952 (9th Cir. 2013) .................................. 3

United States v. Flores-Montano,

541 U.S. 149 (2004) ................................................ 4

United States v. Jones,

565 U.S. 400 (2012) ...................................... 7, 8, 12

United States v. Montoya de Hernandez,

473 U.S. 531 (1985) .......................................... 4, 18

United States v. Ramsey,

431 U.S. 606 (1977) .............................18, 19, 20, 21

Wilkes v. Halifax,

(1765) 95 Eng. Rep. 797 ....................................... 13

Wilkes v. Wood,

(1763) 98 Eng. Rep. 489 ....................................... 13

v

TABLE OF AUTHORITIES

(continued)

Page(s)

CONSTITUTIONAL PROVISIONS

U.S. const. amend IV ............................................. 2, 7

FEDERAL STATUTES

19 CFR § 145.3 (1976) .............................................. 20

19 U.S.C. § 482 ......................................................... 18

19 U.S.C. § 1467 ....................................................... 18

19 U.S.C. § 1583 ....................................................... 20

19 U.S.C. § 1583(c)(2)(A)(B) ..................................... 20

TREATISES

2 WILLIAM BLACKSTONE, COMMENTARIES 2 ............... 9

John Locke, The Second Treatise of

Government § 123 ................................................ 10

John Locke, THE SECOND TREATISE OF

GOVERNMENT § 87 (1690) (C.B. MacPherson

ed., Hackett Publ’g Co. 1980) ................................. 9

OTHER MATERIALS

Gordon S. Wood, THE CREATION OF THE

AMERICAN REPUBLIC, 1776–1787 (1998) ................ 9

Jack Rakove, REVOLUTIONARIES: A NEW

HISTORY OF THE INVENTION OF AMERICA 78

(2010) ...................................................................... 9

James Madison, Property, in 6 THE

WRITINGS OF JAMES MADISON 101

(Gaillard Hunt ed., 1906) ................................. 6, 11

vi

TABLE OF AUTHORITIES

(continued)

Page(s)

JAMES W. ELY, JR., THE GUARDIAN OF

EVERY OTHER RIGHT: A

CONSTITUTIONAL HISTORY OF

PROPERTY RIGHTS 28 (1992) ............................. 8

Leonard W. Levy, ORIGINS OF THE BILL OF

RIGHTS 195 (1999)................................................. 12

Morgan Cloud, Property Is Privacy: Locke and

Brandeis in the Twenty-First Century, 55

Am. Crim. L. Rev. 37 (2018)................................... 8

Morgan Cloud, Searching through History;

Searching for History, 63 The University of

Chicago Law Review 1707 (1996) ........................ 12

Samuel Adams, The Rights of Colonists, The

Report of the Committee of Correspondence

to the Boston Town Meeting, Nov. 20, 1772,

Old South Leaflets no. 173 (Boston:

Directors of the Old South Work, 1906) .............. 10

The Fourth Amendment During The Lochner

Era: Privacy, Property, and Liberty, 48

Stan. L. Rev. 555 (1996) ......................................... 1

William J. Stuntz, The Substantive Origins of

Criminal Procedure, 105 The Yale Law

Journal 393 (1995) ................................................ 11

William John Cuddihy, The Fourth

Amendment: Origins and Original Meaning,

602-1791 (1990) .................................................... 11

1

INTEREST OF AMICUS CURIAE1

Morgan Cloud is a Fourth Amendment scholar

who seeks to assist in the proper understanding of

Fourth Amendment historic principles. Morgan Cloud

is the Charles Howard Candler Professor of Law

Emeritus at Emory University. He has published numerous books and articles on constitutional criminal

procedure and criminal law. Many of his works examine Fourth Amendment issues relevant to this amicus

brief, including The Fourth Amendment During The

Lochner Era: Privacy, Property, and Liberty, 48 Stan.

L. Rev. 555 (1996).

SUMMARY OF ARGUMENT

The text, history, and early traditions of the

Fourth Amendment all demonstrate that both manual and forensic cell phone searches are severe intrusions upon property rights—and the privacy rights

that the founding generation understood to be protected by and encompassed within property rights—

an understanding that directly influenced the ratification of the Fourth Amendment. Unless authorized

by a warrant based on probable cause, searches of the

contents of cell phones are best understood as warrantless searches of the twenty-first century digital

equivalents of eighteenth-century “papers” protected

in the Amendment’s text—and are therefore

1 Pursuant to Supreme Court Rule 37.6, amici curiae state that

no counsel for any party authored this brief in whole or in part

and no entity or person, other than amici curiae, their members,

or their counsel, made any monetary contribution intended to

fund the preparation or submission of this brief. Pursuant to

Rule 37.2, counsel for Petitioner and Respondent received notice

of amici’s intent to file this brief on September 8, 2026.

2

unlawful. Warrantless cell phone searches at the border conflict with this Court’s recent decisions, including Riley v. California, 573 U.S. 373 (2014).

ARGUMENT

I. Introduction

The Court should grant the Petition for Writ of

Certiorari to eliminate the existing uncertainty

caused by the current Circuit split regarding the application of the Fourth Amendment’s warrant requirement to searches of travelers’ cell phones at the

border. Some circuits, including the Fifth Circuit below, have permitted warrantless government

searches of cell phone contents in these circumstances. Such searches run afoul of this Court’s decision in Riley v. California, 573 U.S. 373 (2014). And

these warrantless searches also conflict with the

Fourth Amendment’s text, history, and traditions.

First principles confirm that these intrusions on the

contents of cell phones fall outside the bounds of a

routine border search in any relevant respect and are

unconstitutional searches of the modern equivalent of

“papers.” U.S. Const. Amend. IV.

The text, history, and early traditions of the

Fourth Amendment all demonstrate that both manual and forensic cell phone searches are severe intrusions upon property rights—and the privacy rights

that the founding generation understood to be protected by and encompassed within property rights—

secured by the Fourth Amendment. Unless authorized by a warrant based on probable cause, searches

of the contents of cell phones are best understood as

warrantless searches of the digital equivalents of

3

“papers”2 protected in the Amendment’s text—and

are therefore unlawful.

Indeed, this Court has recognized that searching

cell phone data may be an even greater intrusion into

the private affairs of someone’s life than traditional

searches of houses and effects. Cell phone data can

reveal unprecedented volumes of personal information. The Fourth Amendment commands that they

must be authorized by a judicial warrant based on

probable cause. Riley, supra; Carpenter v. United

States, 585 U.S. 296 (2018); Chatrie v. United States,

146 S. Ct. 2193 (2026).

The extreme violations of constitutional rights

produced by searches of cell phones’ contents are the

same whether conducted in the interior or at the border. Cell phone searches can reveal to the government

the most intimate details of peoples’ lives including

personal medical information, privately held political

views, religious affiliations, and social and romantic

relationships.

Although the government’s power to seize and

search property at the border has been found by this

Court to be extensive, it is not unlimited—and the

2 See, e.g., United States v. Ackerman, 831 F.3d 1292, 1304 (10th

Cir. 2016) (Gorsuch, J.) (“No one in this appeal disputes that an

email is a ‘paper’ or ‘effect’ for Fourth Amendment purposes, a

form of communication capable of storing all sorts of private and

personal details.”); United States v. Cotterman, 709 F.3d 952,

964 (9th Cir. 2013) (recognizing that digital information is equivalent to “personal ‘papers’”); LeClair v. Hart, 800 F.2d 692, 696

n.5 (7th Cir. 1986) (recognizing that information is a form of

property). See also Chatrie v. United States, 146 S. Ct. 2193, 2220

(2026).

4

border search exception has generally been framed in

terms of the ability of the government to detect contraband and to levy duties on imports. See United

States v. Montoya de Hernandez, 473 U.S. 531, 537

(1985) (“Congress has granted the Executive plenary

authority to conduct routine searches and seizures at

the border, without probable cause or a warrant, in

order to regulate the collection of duties and to prevent

the introduction of contraband into this country.”)

(emphasis added). See also United States v. FloresMontano, 541 U.S. 149, 152 (2004). Neither justification for allowing warrantless “routine” border

searches justifies promiscuous intrusions into a traveler’s text messages, photos, and emails.

Even at the border, a person’s right to be secure

against unreasonable searches and seizures is

“[b]alanced against the sovereign’s interests.” Montoya de Hernandez, 473 U.S. at 539. Although the balance “is qualitatively different . . . than in the interior”

and is “struck much more favorably to the Government,” id. at 538, 540, the touchstone of the Fourth

Amendment analysis is reasonableness. Id. at 538.

Judged against the text, history, and traditions of the

Fourth Amendment, both “manual” and “forensic”

searches of the contents of cell phones are unreasonable without a warrant based on probable cause. The

goals of the “border exception” to the Fourth Amendment, if triggered at all, are outweighed by the extreme incursions on property and privacy rights.

In Riley this Court held that the categorical rule

permitting searches of “physical objects” incident to

arrest did not justify warrantless searches of the “digital content on cell phones.” Riley, 573 U.S. at 386.

5

This distinction between physical objects and the contents of expressive property, like private papers and

the contents of cell phones, is as old as the Fourth

Amendment—and it applies equally in the border

context.

This Court’s recent decisions requiring warrants

for searches of cell phone data have largely relied

upon the reasonable expectation of privacy standard

first articulated in the late twentieth century. The

property-based rules embedded in the Fourth Amendment’s text, history, and traditions produce the same

result in this case. Government searches of the contents of expressive property like cell phone contents

and private papers are unconstitutional, even if conducted at the border, unless authorized by a warrant

based on probable cause.

II. Both Property and Privacy Rules Require a

Warrant Based on Probable Cause for

Searches of the Contents of Expressive

Property

A. The Fourth Amendment Text and the

Contents of Papers

The Fourth Amendment explicitly protects persons and three types of property: houses, papers, and

effects. The separate designation of papers would be

redundant if the founders only intended to protect papers as a form of physical, tangible, personal property,

because the text also explicitly protects effects.3 The

3 See Chatrie, 146 S. Ct. at 2220 (Gorsuch, J., concurring in the

judgment) (The term effects “was understood at the time of the

Fourth Amendment’s adoption to embrace most any kind of personal property.”)

6

Amendment’s origins reveal that the distinction between papers and other effects rested on a fundamental English and American belief that a person’s ideas,

religious beliefs, and political theories, and the expression of them, particularly in his papers, were his

most treasured property. For example, contemporaneously with the ratification of the Bill of Rights

James Madison wrote that “a man has a property in

his opinions and the free communication of them,

[and] has a property of peculiar value in his religious

opinions, and in the profession and practice dictated

by them.”4

The Fourth Amendment text distinguishes “papers” from other effects precisely because papers are

not merely physical property. The contents of papers

are expressive property that can reveal the most intimate details of a person’s life including one’s political

views, religious beliefs, and medical information. As a

matter of common sense and current usage, a cell

phone operates as, among other things, the modernday equivalent of “papers” because this is today's

technology for storing and communicating the personal details of our lives to others.

B. The Fourth Amendment Protects Both

Property and Privacy Rights

The government can violate the Fourth

Amendment in at least two ways: by transgressing

4 James Madison, Property (1792) (emphasis added). Ratification

of the Bill of Rights was completed on December 15, 1791. Madison’s essay Property was published in the National Gazette on

March 29, 1792. The essay can be found in James Madison, Property, in 6 The Writings of James Madison 101 (Gaillard Hunt ed.,

1906).

7

property rights, or by violating an individual’s

reasonable expectation of privacy. See United States

v. Jones, 565 U.S. 400, 404–08 (2012); Soldal v. Cook

County, 506 U.S. 56, 62–64 (1992); see also Katz v.

United States, 389 U.S. 347, 351–53 (1967); Chatrie,

146 S. Ct. at 2204-2205. These two concepts of rights

are not mutually exclusive. In some cases, “an alignment of the two approaches occurs,” Chatrie, 146 S.

Ct. at 2205 n.5, most obviously where government

agents search the contents of private papers or their

contemporary equivalents, data stored in digital devices like cell phones.

By guaranteeing the right of the people “to be secure in their persons, houses, papers, and effects” U.S.

Const. amend. IV, the text reveals the Fourth Amendment’s “close connection to property.” Jones, 565 U.S.

at 404-405. Although the text does not use the word

privacy, this omission did not signal that the Framers

were unfamiliar with or unconcerned about protecting personal privacy from government searchers. Indeed, this Court has recognized that “[f]rom the

founding onward . . . the Fourth Amendment has

sought to secure the ‘privacies of life’ against the exercise of ‘arbitrary power,’” Chatrie, 146 S. Ct. at 2205

(quoting Boyd v. United States, 116 U.S. 616, 630

(1886)). “Whatever the form of an attempted incursion, the Fourth Amendment protects Americans’

long-held conviction that no government official

should have free access to the most closely kept aspects of their lives.” Chatrie, 146 S. Ct. at 2205.5

See also Terrence Byrd v. United States, 584 U.S. 395, 403

(2018); Florida v. Jardines, 569 U. S. 1, 11 (2013); Jones, 565

5

8

This has been true since the Founding era. Eighteenth century Whig theory used property rights to

protect what we now refer to as privacy rights. “[T]he

colonial leaders drew heavily on the time-honored

English Whig philosophy that regarded protection of

private property as crucial to the preservation of freedom.” James W. Ely, Jr., The Guardian of Every

Other Right: A Constitutional History of Property

Rights 28 (1992).

The Fourth Amendment unsurprisingly employs

an Eighteenth century vocabulary. “‘[P]rivacy,’ by

contrast, ‘was not part of the political vocabulary of

the [founding]. Instead, liberty and privacy rights

were understood largely in terms of property rights.’”

Carpenter, 585 U.S. at 348 (Thomas, J., dissenting)

(quoting Morgan Cloud, Property Is Privacy: Locke

and Brandeis in the Twenty-First Century, 55 Am.

Crim. L. Rev. 37, 42 (2018).) Although they employed

different terminology in the text of the Fourth

Amendment, “the founding generation understood

that, by securing their property, the Fourth Amendment would often protect their privacy as well.” Carpenter, 585 U.S. at 350 (Thomas, J., dissenting).

C. The Meaning of Property at the Founding

1. John Locke’s Theory of Property

To be sure, eighteenth century political theory defined property to include tangible things that one can

own, modify, control, and from which one can exclude

others. For example, Blackstone wrote that property

U.S. at 406-407; Kyllo v. United States, 533 U.S. 27, 30-31 (2001);

Soldal, 506 U. S. at 64-65.

9

was “that sole and despotic dominion which one . . .

claims and exercises over the external things of the

world, in total exclusion of the right of any other individual in the universe.” 2 William Blackstone, Commentaries 2.

But the Whig theory of property that animated

the Revolution and the Founding also relied upon an

expansive theory of property that included far more

than just tangible things. John Locke’s famous definition articulates this broad theory of property succinctly: a man’s property is “his life, liberty and estate.” John Locke, The Second Treatise of Government

§ 87 (emphasis added) (1690) (C.B. MacPherson ed.,

Hackett Publ’g Co. 1980).

Locke asserted that a person’s property was not

limited to the objects he possessed. For example, a

person’s rights were his property. Property rights

served as a fundamental tool for protecting other

rights, including the privacies of life, and this broad

theory of property was a compelling force in the American revolutionary and founding eras. See Jack Rakove, Revolutionaries: A New History of the Invention

of America 78 (2010) (noting that “property was one of

the strongest words in the Anglo-American political

vocabulary.”)6

To Locke, the ultimate reason people abandon the

freedom of nature and accept the constraints inherent

in living in society is “for the mutual preservation of

6 See also, Gordon S. Wood, The Creation of the American Re-

public, 1776–1787, 219 (1998) (“Eighteenth-century Whiggism

had made no rigid distinction between people and property.”)

10

their lives, liberties and estates, which I call by the

general name, property.” Second Treatise § 123 (emphasis added). Major figures in the founding generation echoed Locke’s focus on property rights. See, e.g.,

Samuel Adams, The Rights of Colonists, The Report

of the Committee of Correspondence to the Boston

Town Meeting, Nov. 20, 1772, Old South Leaflets no.

173 (Boston: Directors of the Old South Work, 1906)

7: 419 (“the grand end of civil government, from the

very nature of its institution, is for the support, protection, and defence of those very rights; the principal

of which, as is before observed, are Life, Liberty, and

Property”).

2. James Madison’s Broad Theory of Property

Many founding era writers documented Locke’s

influence on the ideas, politics and rights that propelled the American Revolution and the creation of

the Constitution. No document is more important for

understanding the relationship between property and

our constitutional rights than James Madison’s essay

Property, published only three months after the ratification of the Bill of Rights.7

In this essay, Madison spent little time discussing the narrow concept of property, which he defined

as “external things of the world [like] land, or merchandize, or money.” James Madison, Property (1792).

Instead, Madison devoted the majority of his essay to

explaining why material possessions are not the most

important forms of property. “In its larger and juster

meaning, it [property] embraces every thing to which

7 James Madison, Property, supra note 4.

11

a man may attach a value and have a right; and which

leaves to every one else the like advantage.” Id. (emphasis added).

The most important property to which a man may

attach value, Madison wrote, consists of his ideas, beliefs, faith, and the right to express them. Id. On the

heels of ratification of the Bill of Rights, Madison

warned that a government that “directly violates the

property which individuals have in their opinions,

their religion, their persons, and their faculties . . . is

not a pattern for the United States.” Id.

Defining a person’s most treasured property as

his ideas, beliefs, abilities, and the opportunity to express and exercise them captures the theoretical foundations of the Fourth Amendment’s special concern

for the contents of papers. In this regard, the Fourth

Amendment is tethered to the Fifth Amendment privilege against self-incrimination and the First Amendment guarantees of freedom of speech, thought, and

religion. All of these have roots in the sixteenth and

seventeenth century English religious conflicts that

culminated with the Glorious Revolution and the

British Bill of Rights. From at least 1580 until 1689,

English rulers employed violent methods—forcefully

searching homes for evidence of heresy and sedition,

coercing confessions, often with torture, to expose disfavored religious or political beliefs, and executions—

to repress religious and political opposition.8

8 See, e.g., William John Cuddihy, The Fourth Amendment: Ori-

gins and Original Meaning, 602-1791, pp. 103-118, 136-167, 193

(1990); William J. Stuntz, The Substantive Origins of Criminal

Procedure, 105 The Yale Law Journal 393, 414-416, 419 (1995);

Morgan Cloud, Searching through History; Searching for

12

As Madison’s essay demonstrates, protecting a

person’s thoughts and beliefs contained in expressive

property from abusive government acts was a core

principle for the nation’s founders.

III. Protections for the Contents of Papers

A. British Paper Searches on the Eve of the

Revolution

British searches and seizures triggered by antigovernment publications provided direct historical

sources for the Fourth Amendment’s explicit protections of a person’s “papers.” Indeed, no British judicial decision is more celebrated as a source of the

Fourth Amendment than Entick v. Carrington, 95

Eng. Rep. 807 (C. P. 1765), which this Court continues

to embrace as a “‘monument of English freedom’ ‘undoubtedly familiar’ to ‘every American statesman’ at

the time the Constitution was adopted, and considered to be ‘the true and ultimate expression of constitutional law’ with regard to search and seizure.”

Jones, 565 U.S. at 405 (citing Brower v. County of

Inyo, 489 U.S. 593, 596 (1989) (quoting Boyd v. United

States, 116 U.S. 616, 626, (1886))).

Entick, whose “propositions” this Court has “confidently” concluded “were in the minds of those who

framed the fourth amendment to the constitution,”

Boyd, 116 U.S. at 626-27, is a critical source for understanding why papers are a special type of property

deserving the most stringent constitutional protections. In the early 1760s, British agents searched for

History, 63 The University of Chicago Law Review 1707, 17171718 (1996); Leonard W. Levy, Origins of the Bill of Rights 195

(1999).

13

papers to prove they contained seditious content.

These searches and seizures for evidence related to

publications criticizing the English government generated a number of lawsuits that directly influenced

the creation of the Fourth Amendment..9

As happens during twenty-first century seizures

and searches of cell phones, British agents committed

physical trespasses on tangible personal property

while searching for dissident papers. A second intrusion occurred when government agents read the papers’ contents. Although reading may not have been a

literal physical trespass, Lord Camden stressed that

both types of intrusions violated the victims’ rights

and English law.

Lord Camden rejected government arguments

that the power to conduct these searches “is essential

to government, and the only means of quieting clamours and sedition.” Entick v. Carrington, 19 How. St.

Tr. 1029, 1064 (C. P. 1765). Searches for seditious papers inevitably led to the exposure of private papers.

And like this Court’s concerns about the expansive intrusions resulting from reading a cell phone’s contents, Riley, 573 U.S. at 394-95, Lord Camden

stressed that, as a practical matter, allowing

9 Entick challenged searches for evidence related to several is-

sues of The Monitor, or British Freeholder. Most of the litigation

resulted from publication of North Briton No. 45, including

Money v. Leach, (1765) 97 Eng. Rep. 1075; 19 How. St. Tr. 1001;

Wilkes v. Halifax, (1765) 95 Eng. Rep. 797; 19 How. St. Tr. 1406;

Beardmore v. Carrington, (1764) 95 Eng. Rep. 790; 19 How. St.

Tr. 1405; Huckle v. Money, (1763) 95 Eng. Rep. 768; 19 How. St.

Tr. 1404; and Wilkes v. Wood, (1763) 98 Eng. Rep. 489; 19 How.

St. Tr. 1153.

14

government to read private papers expanded the

scope of the government intrusions. “[W]hen the messengers hesitated about taking all the manuscripts,

and sent to the secretary of state for more express orders for that purpose, the answer was, ‘that all must

be taken, manuscripts and all.’” Entick, 19 How. St.

Tr. at 1065.

Echoing Locke and anticipating Madison, Lord

Camden described the relationship between property

and liberty:

The great end, for which men entered

into society, was to secure their property.

. . . By the laws of England, every invasion of private property, be it ever so minute, 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 . . . . Id. at 1066.

Lord Camden also emphasized that English

rights protected with equal vigor intangible property,

like the contents of papers:

There is no process against papers in

civil causes . . . . In the criminal law such

a proceeding was never heard of; and yet

there are some crimes, such for instance

as murder, rape, robbery, and housebreaking, to say nothing of forgery and

perjury, that are more atrocious than libelling. But our law has provided no paper search in these cases to help forward

the conviction. Id. at 1073.

15

Lord Camden’s condemnation of dragnet

searches of private papers is mirrored by this Court’s

recent decisions requiring warrants for searches of

cell phone data. As this Court stated in Riley, “a cell

phone search would typically expose to the government far more than the most exhaustive search of a

house.” 573 U.S. at 396.

B. Early Supreme Court Decisions Protecting the Contents of Papers Under the

Fourth Amendment

In two early decisions interpreting the Fourth

Amendment, Ex Parte Jackson and Boyd v. United

States, the Supreme Court acted to shield the expressive contents of private papers from government intrusions.

1. Ex Parte Jackson

The Supreme Court’s first important decision interpreting the Fourth Amendment confirmed that a

warrant based on probable cause is required for government searches of the expressive contents of private letters. In Ex Parte Jackson, the Court affirmed

that Congress can regulate what is sent through the

U.S. mails, but also emphasized constitutional restrictions on government power to open private letters to examine their contents. Ex Parte Jackson, 96

U.S. 727 (1877).

Jackson was convicted of violating a federal statute prohibiting anyone from “knowingly” depositing

or sending any “letter or circular concerning” lotteries

“in the mail.” Jackson mailed “a circular” promoting a

lottery in an envelope. He was “sentenced to pay a fine

of $100, with the costs of the prosecution, and to be

16

committed to the county jail until the fine and costs

were paid.” Id. Jackson filed a petition for a writ of

habeas corpus, arguing that his imprisonment was illegal because the statute under which he was convicted was unconstitutional and void. Id.

The Supreme Court denied the writ, concluding

that the Constitution empowered Congress to regulate what could be sent in the mails. Id. at 732. But

the Court also recognized that this authority did not

confer unrestricted power to enforce those regulations

by reading the letter’s contents. Rather, in the law’s

enforcement, a distinction is to be made

between different kinds of mail matter,

— between what is intended to be kept

free from inspection, such as letters, and

sealed packages subject to letter postage; and what is open to inspection, such

as newspapers . . . and other printed

matter, purposely left in a condition to

be examined. Id. at 732-733.

The Fourth Amendment’s “great principle”, the

Court observed, “extends to their papers, thus closed

against inspection, wherever they may be,” and

“[w]hilst 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.” Id. at 733.

2. Boyd v. United States

Eight years after issuing its opinion in Ex Parte

Jackson, this Court decided Boyd v. United States,

116 U.S. 616 (1886). Boyd relied directly on Entick v.

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Carrington to define the limits the Fourth Amendment imposed on government searches and seizures

of property. In Boyd, the United States filed a civil

forfeiture action against E.A. Boyd & Sons (the

Boyds), claiming that they had violated customs laws

by importing cases of plate glass without paying the

required duties. The government obtained a subpoena

compelling the Boyds to produce business records in

court, where government lawyers read their contents

to secure a forfeiture verdict at trial. The Boyds argued that this was an unreasonable seizure and

search of the documents. See Boyd, 116 U.S. at 630.

This Court agreed, confirming that most government

searches of private papers to obtain evidence for use

in a criminal (or civil forfeiture) trials violated the

Fourth Amendment, as well as the Fifth Amendment

privilege against self-incrimination.

Thus, early English law which informed the principles adopted by the Founders, as well as early decisions of the Supreme Court, confirm that the Fourth

Amendment demands that searches of the contents of

a person’s papers must be authorized by a warrant

based on probable cause.

IV. Requiring a Warrant to Search Cell Phone

Contents Is Consistent with Customs Laws

Dating Back to the First Congress

That this case arises at the border does not diminish the Fourth Amendment’s protections of the

contents of a traveler’s “papers”—including their

modern analogs. Indeed, beginning with the first Congress, federal legislation has limited the categories of

18

property subject to searches by customs officers.10 As

this Court has recognized, “Congress has granted the

Executive plenary authority to conduct routine

searches and seizures at the border, without probable

cause or a warrant, in order to regulate the collection

of duties and to prevent the introduction of contraband

into this country.” Montoya de Hernandez, 473 U.S. at

537 (emphasis added).

But Customs searches must be for these specified

legislative purposes in order to fall within the border

search exception. Customs laws grant discretion to

search for property related to customs violations, and

this subject matter limitation imposes significant restrictions on searches of the contents of expressive

property. Current federal statutes permit searches of

packages, including “letter-class mail,” but only if

“reasonable cause to suspect’” that the envelope’s contents violate customs laws exists. United States v.

Ramsey, 431 U.S. 606, 607 (1977) (emphasis added).

10 This early statute allowed customs enforcers “to enter any ship

or vessel, in which they shall have reason to suspect any goods,

wares or merchandise subject to duty shall be concealed; and

therein to search for, seize, and secure any such goods, wares or

merchandise.” United States v. Ramsey, 431 U.S. 606, 616, n. 12

(1977). See also 19 U.S.C. § 1467 (authorizing “inspection, examination, and search ... of the persons, baggage, and merchandise

discharged or unladen [when] a vessel from a foreign port or

place … arrives at a port or place in the United States”); Ramsey,

431 U.S. at 611-613 (an 1866 statute permits authorized persons

“to board or search vessels may ... search any trunk or envelope,

wherever found, in which he may have a reasonable cause to suspect there is merchandise which was imported contrary to

law....”) (citing 19 U.S.C. § 482)).

19

Limiting the scope of customs searches to contraband and dutiable property is a principle dating back

to a statute enacted by the first Congress. As this

Court observed in Ramsey, “[t]he historical importance of the enactment of this customs statute by

the same Congress which proposed the Fourth

Amendment is, we think, manifest.” Id. at 616-617

(quoting Boyd, 116 U.S. at 623). In Boyd, the Court

emphasized that as the first customs statute “was

passed by the same Congress which proposed for

adoption the original amendments to the Constitution, it is clear that the members of that body did not

regard searches and seizures” designed to effect “the

seizure of stolen goods” or the “seizure of goods forfeited for a breach of the revenue laws, or concealed to

avoid the duties payable on them” as “unreasonable”

within the “prohibition of the [Fourth] amendment.”

Boyd, 116 U.S. at 623 (emphasis added).11

By contrast, most cell phone searches are unlikely to lead to the discovery or seizure of stolen

goods carried by the traveler at the time of the search,

goods forfeitable for nonpayment of duties, or goods

concealed to avoid duties. This is because these devices are incapable of housing the tangible things that

might themselves constitute a customs violation.

This physical reality is critical because, although federal law authorizes customs agents to search packages for “merchandise which was imported contrary

11 Boyd did not ban all papers searches. For example, it permit-

ted searches for contraband and imported goods on which duties

had not been paid consistent with constitutaionl and statutory

requirements. Boyd, 116 U.S. at 623.

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to law,” it specifically requires agents to obtain a warrant before reading mail. Ramsey, 431 U.S. at 611612. Thus, even if cell phone searches could theoretically reveal evidence of independent customs violations, the phone itself would not contain contraband

or dutiable imports the way that luggage or a shipment of goods might.

Indeed, the same federal statute granting Customs officers discretion to seize and search objects

crossing the nation’s international borders also imposes a warrant requirement for reading the contents

of personal letters. 19 U.S.C. § 1583 (emphasis added).

The statute commands that no person authorized to

search by the statute “(1) shall read, or authorize any

other person to read, any correspondence contained in

mail sealed against inspection unless prior to so reading—(A) a search warrant has been issued…; or (B)

the sender or addressee has given written authorization for such reading.” 19 U.S.C. § 1583(c)(2)(A)(B).

Similarly, this Court has held that although an

officer possessing “reasonable cause to believe” that

customs laws are being violated can open an envelope,

“postal regulations flatly prohibit, under all circumstances, the reading of correspondence absent a

search warrant.” Ramsey, 431 U.S. at 623 (citing 19

CFR § 145.3 (1976)). In Ramsey, this Court emphasized that a customs agent’s search of “envelopes” did

not violate the Fourth Amendment because the agent

possessed facts supplying “reasonable cause to suspect” that there was merchandise or contraband in the

envelopes. The statute authorized the warrantless

search because agents limited the intrusion to an inspection of the envelope’s physical contents, and did

21

not read the contents of the private papers. Ramsey,

431 U.S. at 612-615.

Government agents at the border are authorized

to search property to collect import duties or find contraband. To comply with the border exception to the

Fourth Amendment, searches of cell phone contents

must be reasonable in furtherance of the purposes underlying the exception. See Riley, 573 U.S. at 386 (analyzing cell phone searches against the backdrop of

the policy concerns justifying the search incident to

arrest exception and finding “no comparable risks

when the search is of digital data”).

Warrantless searches at the border do not further

any of the exception’s purposes. This is because

searches of cell phone contents bear “little resemblance to the type of brief physical search[es]” permitted by the border search exception. Cf., Riley, 573 U.S.

at 386. Searches of these expressive contents are constitutional only when authorized by a warrant based

on probable cause.

CONCLUSION

For the reasons stated above, the Petition for

Writ of Certiorari should be granted.

Respectfully submitted,

Alexander N. Ely

Counsel of Record

O’MELVENY & MYERS LLP

1625 I Street, NW

Washington, DC 20006

(202) 383-5370

aely@omm.com

Mark A. Racanelli

Brian Mucyo

O’MELVENY & MYERS

LLP

1301 AVENUE OF THE

AMERICAS, FL. 17

NEW YORK, NY 10019

22

Skyanne Simonson

O’MELVENY & MYERS

LLP

2801 N HARWOOD ST STE

1600, DALLAS, TX 75201

September 18, 2026