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

No. 26-208

IN THE

Supreme Court of the United States

____________________

GEORGE ANIBOWEI,

Petitioner,

v.

TODD BLANCHE, ATTORNEY GENERAL,

ET AL.,

Respondents.

________________________

On Petition for Writ of Certiorari to the

United States Court of Appeals

for the Fifth Circuit

_______________________

BRIEF OF FOURTH AMENDMENT SCHOLARS

AS AMICI CURIAE IN SUPPORT

OF PETITIONER

_______________________

ANTON METLITSKY

(Counsel of Record)

O’MELVENY & MYERS LLP

1301 Ave. of the Americas

17th Floor

New York, NY 10019

(212) 326-2000

ametlitsky@omm.com

TIMUR AKMAN-DUFFY

GILLIAN MAK

O’MELVENY & MYERS LLP

1625 Eye Street, N.W.

Washington, D.C. 20006

Attorneys for Amici Curiae

i

TABLE OF CONTENTS

Page

INTEREST OF AMICI CURIAE .............................. 1

INTRODUCTION AND SUMMARY OF ARGUMENT ........................................................ 1

ARGUMENT ............................................................. 3

I.

THIS COURT HAS REPEATEDLY

RECOGNIZED THAT FOURTH

AMENDMENT PRINCIPLES DEVELOPED FOR THE PHYSICAL WORLD

CANNOT BE MECHANICALLY APPLIED TO DIGITAL SEARCHES. .................. 3

II.

THE BORDER EXCEPTION CANNOT

AND SHOULD NOT APPLY TO CELL

PHONE SEARCHES. ..................................... 10

A.

The Logic Of The Border Exception

Is Fundamentally Rooted In The

Physical World. ....................................... 10

B.

The Logic Of The Border Exception

Does Not Translate To The Digital

World. ...................................................... 11

C.

Comparing The Diminished Government Interest In A Warrantless

Search To The Immense Intrusion

On Privacy, The Border Exception

As Applied To Digital Devices

Searches Is Unreasonable. ..................... 13

III. THE COURT SHOULD RESOLVE THE

QUESTION PRESENTED NOW. .................. 20

CONCLUSION ........................................................ 24

ii

TABLE OF AUTHORITIES

Page(s)

Cases

Alasaad v. Mayorkas,

988 F.3d 8 (1st Cir. 2021) ..................................... 23

Anibowei v. Bondi,

2025 WL 3231720 (5th Cir. Nov. 19, 2025) ... 21, 23

Boyd v. United States,

116 U.S. 616 (1886) ........................................ 13, 20

Carpenter v. United States,

585 U.S. 296 (2018) ............................ 4-8, 10, 19-20

Chatrie v. United States,

146 S. Ct. 2193 (2026) ............ 2, 8-10, 15-17, 20, 23

Johnson v. United States,

333 U.S. 10 (1948) ................................................ 17

Katz v. United States,

389 U.S. 347 (1967) ................................................ 4

Kyllo v. United States,

533 U.S. 27 (2001) ........................................ 1, 4, 10

Riley v. California,

573 U.S. 373 (2014) .................. 2, 4-5, 13-15, 17, 20

Silverman v. United States,

365 U.S. 505 (1961) ................................................ 4

United States v. Alisigwe,

No. 24-960, slip op. (2d Cir. Sept. 17, 2026) ....... 23

United States v. Cano,

934 F.3d 1002 (9th Cir. 2019) .............................. 23

United States v. Cotterman,

709 F.3d 952 (9th Cir. 2013) ................................ 21

iii

TABLE OF AUTHORITIES

(continued)

Page(s)

United States v. Flores-Montano,

541 U.S. 149 (2004) ........................................ 11, 13

United States v. Jones,

565 U.S. 400 (2012) ...............................4, 16, 18, 19

United States v. Kolsuz,

890 F.3d 133 (4th Cir. 2018) ................................ 20

United States v. Montoya de Hernandez,

473 U.S. 531 (1985) ........................................ 11, 13

United States v. Ramsey,

431 U.S. 606 (1977) .................................. 11, 13, 18

United States v. Robinson,

414 U.S. 218 (1973) ................................................ 4

United States v. Touset,

890 F.3d 1227 (11th Cir. 2018) ............................ 20

Constitutional Provisions

U.S. Const. amend. IV ............................................... 2

Other Authorities

Andrew Guthrie Ferguson, Digital

Policing After Chatrie (July 24, 2026) ............... 8, 9

Andrew Guthrie Ferguson, Digital

Rummaging, 101 Wash. U. L. Rev.

1473 (2024) ............................................... 18, 19, 22

Andrew Guthrie Ferguson, FutureProofing the Fourth Amendment,

Harv. L. Rev. Blog (June 25, 2018),

https://perma.cc/4583-3KFR .................................. 7

iv

TABLE OF AUTHORITIES

(continued)

Page(s)

Andrew Guthrie Ferguson, Why Digital

Policing Is Different, 83 Ohio St. L.J.

817 (2022) ......................................................... 4, 14

Bryan Sykes, Border Search Rationales

Ripe for Abuse, with Journalists

Particularly at Risk, 45 Hastings

Comm. & Ent. L.J. 165 (2023) ............................. 18

Elizabeth E. Joh, Artificial Intelligence and

Policing: Hints in the Carpenter Decision,

16 Ohio St. J. Crim. L. 281 (2018) ............. 7, 17, 19

Elizabeth E. Joh, Privacy Protests: Surveillance

Evasion and Fourth Amendment Suspicion,

55 Ariz. L. Rev. 997 (2013) ............................. 21, 22

Erin Murphy, Databases, Doctrine, and

Constitutional Criminal Procedure,

37 Fordham Urb. L.J. 803 (2010)........................... 7

Erin Murphy, The Politics of Privacy in the

Criminal Justice System: Information

Disclosure, the Fourth Amendment, and

Statutory Law Enforcement Exemptions,

111 Mich. L. Rev. 485 (2013) ................................ 14

Gaya Gupta & Angie Orellana Hernandez,

Border Agents Ask Lawyer With ProPalestinian Client to Give Up Phone,

Wash. Post (Apr. 8, 2025),

https://www.washingtonpost.com/2025/0

4/08/michigan-lawyer-border-phone/ ................... 21

v

TABLE OF AUTHORITIES

(continued)

Page(s)

Orin Kerr, The Digital Fourth

Amendment: Privacy and Policing in

Our Online World 123 (2025) ............................... 11

U.S. Customs & Border Prot. CBP

Directive No. 3340-049B, Border Search

of Electronic Devices (Jan. 1, 2026) ...................... 19

U.S. Customs & Border Prot., Border Search

of Electronic Devices at Ports of Entry

(updated Aug. 4, 2026),

https://www.cbp.gov/travel/dbp-searchauthority/border-search-electronic-devices ......... 23

U.S. Customs & Border Prot., CBP

Home Mobile App,

https://www.cbp.gov/about/mobileapps-directory/cbphome ....................................... 16

U.S. Customs & Border Prot., CBP Releases

Statistics on Electronic Device Searches

(Apr. 11, 2017),

https://www.cbp.gov/newsroom/nationalmedia-release/cbp-releases-statisticselectronic-device-searches-0 ................................. 23

U.S. Customs & Border Prot., Mobile

Passport Control (MPC),

https://www.cbp.gov/travel/uscitizens/mobile-passport-control .......................... 16

1

INTEREST OF AMICI CURIAE1

Amici are legal scholars who teach and write on

Fourth Amendment law. Professor Andrew Guthrie

Ferguson’s scholarship examines how emerging

technologies reshape policing and constitutional privacy. Professor Erin Murphy writes on criminal procedure, privacy, and the use of scientific and technological tools in law enforcement. Professor Elizabeth

Joh focuses on policing, surveillance, and the legal

implications of new investigative technologies.

Amici have an interest in ensuring that courts

apply longstanding Fourth Amendment principles in

a manner that accounts for the profound privacy

changes caused by new technologies.

INTRODUCTION AND

SUMMARY OF ARGUMENT

The Fourth Amendment’s protections remain

constant, but their application must account for continual changes in technology. This Court has recognized that principle across decades. It refused to

leave privacy of the home “at the mercy of advancing

technology” in thermal imaging. Kyllo v. United

States, 533 U.S. 27, 35 (2001). It acknowledged that

1 Pursuant to Rule 37.6, counsel for amici curiae states that

no counsel for a party authored this brief in whole or in part,

and no counsel or party made a monetary contribution intended

to fund the preparation or submission of this brief. No person

other than amici curiae or their counsel made a monetary contribution to the preparation or submission of the brief. Pursuant to Rule 37.2, counsel of record for all parties received notice

of amici’s intent to file this brief at least 10 days prior to due

date.

2

cell-phone searches are not akin to searches of physical objects because cell phones “differ in both a

quantitative and a qualitative sense.” Riley v. California, 573 U.S. 373, 393 (2014). And just this past

Term, the Court recognized that the Fourth

Amendment protected a person’s cell-phone location

data, ensuring that technological “innovations” do

not unconstitutionally expand “the Government’s

capacity to encroach upon areas normally guarded

from inquisitive eyes.” Chatrie v. United States, 146

S. Ct. 2193, 2205–06 (2026) (quotation omitted).

“Where the Fourth Amendment applies, it applies,”

whether the search involves paper and ink or ones

and zeros. Id. at 2210.

The border-search exception requires the same

review in the face of new digital technologies. The

exception developed around the Government’s authority to control the physical entry of people and

goods into the country. Digital devices do not fit

neatly within that framework. Unlike a backpack,

which contains what a traveler physically brings

across the border, a cell phone provides access to

vast amounts of digital information unrelated to the

journey and that need not cross the border at all.

Applying the border-search rule to digital information gives the Government access far beyond anything contemplated by the cases that shaped the exception. The Fourth Amendment protects against

“unreasonable

searches

and

seizures.”

U.S. Const. amend. IV. The logic underlying the

reasonableness of searching the limited contents of a

suitcase does not carry over to searching a device

containing years of personal data.

3

Until the border-search exception is clarified,

lower courts will continue to struggle with how to

apply the old rule to this new setting—already resulting in different privacy protections at different

ports of entry. Fourth Amendment rights should not

be dependent on where one enters the United States.

This Court should grant certiorari to resolve that

disagreement and explain how Fourth Amendment

protections apply when an exception built for physical entry is used to justify access to digital information.

ARGUMENT

I.

THIS COURT HAS REPEATEDLY RECOGNIZED THAT FOURTH AMENDMENT

PRINCIPLES DEVELOPED FOR THE

PHYSICAL WORLD CANNOT BE MECHANICALLY APPLIED TO DIGITAL

SEARCHES.

The question presented in the Petition—whether

the border exception to the Fourth Amendment justifies access to a traveler’s entire digital life—requires

this Court to once more grapple with how precedent

developed for searches of physical objects and limited records interacts with the digital world. When

the Court developed the border exception, allowing

the government to search persons and goods entering the country, it was not contemplating a search

that exposed a traveler’s entire digital life. As this

Court has made clear in several cases, digital

searches are simply different than physical ones.

Determining how the Fourth Amendment applies to

such searches will require the Court to yet again eschew applying old precedent mechanically to “novel

4

circumstances,” Carpenter v. United States, 585 U.S.

296, 309 (2018), and to reject “simplistic analogies to

non-digital precedent” that “no longer ma[ke] sense

in a digital age.” Andrew Guthrie Ferguson, Why

Digital Policing Is Different, 83 Ohio St. L.J. 817,

833 (2022).

Indeed, this Court has repeatedly confronted

similar problems of the interaction of old Fourth

Amendment precedent and new technology to facilitate government searches. See, e.g., United States v.

Jones, 565 U.S. 400, 404–05 (2012) (GPS tracking);

Kyllo, 533 U.S. at 34–35 (thermal imaging); Katz v.

United States, 389 U.S. 347, 352–53 (1967) (electronic eavesdropping); Silverman v. United States, 365

U.S. 505, 509–12 (1961) (electronic listening device).

Cell phones have brought the distinction between a

physical search and a digital one into sharp focus.

The Court’s prior approach should guide the Court’s

consideration of the question presented here.

1. For instance, the search-incident-to-arrest exception historically permitted officers to search an

arrestee’s person and any physical items found

there, both to protect themselves from concealed

weapons and to prevent the destruction of evidence

within the arrestee’s reach. See United States v.

Robinson, 414 U.S. 218 (1973). But in Riley v. California, 573 U.S. 373 (2014), this Court considered

whether police could search the digital contents of a

phone simply because they had lawfully arrested the

person carrying it. Finding the exception inapplicable, the Court reasoned that the underlying rationale

of the search-incident-to-arrest exception did not

carry over to digital data. Unlike a physical object

that might conceal a threat, “[d]igital data stored on

5

a cell phone cannot itself be used as a weapon,” and

once the phone is secured, “data on the phone can

endanger no one.” Riley, 573 U.S. at 387. Officers

could inspect the phone to determine whether “a razor blade [was] hidden between the phone and its

case.” Id. But the risk mitigation and evidential destruction that justified the physical search of the

phone could not be repurposed to search what it

stores.

The privacy interests were different too. Cell

phones “differ in both a quantitative and a qualitative sense from other objects” because of the volume

and character of the information they contain. Id. at

393. That a phone “now allows an individual to carry such information in his hand does not make the

information any less worthy of the protection for

which the Founders fought.” Id. at 403. A search of

the phone’s data presented the same privacy intrusions that trigger Fourth Amendment protections.

Any exception authorizing a search of its data instead had to “rest on its own bottom.” Id. at 393.

Absent such a justification, the answer was “accordingly simple—get a warrant.” Id. at 403.

2. Only a few years later, the Court again confronted how established Fourth Amendment principles should apply to a new form of digital search.

Carpenter examined whether the government could

obtain historical cell-site location records from a

wireless carrier without a warrant. The government

invoked the third-party doctrine, which generally

treats information voluntarily conveyed to another

as outside Fourth Amendment protection. See Carpenter, 585 U.S. at 308.

6

Rejecting a mechanistic application of the thirdparty doctrine, the Court noted that the search in

question was different in kind from the typical information sought from third-parties. That precedent

concerned bank records and telephone numbers dialed by a user—which revealed limited categories of

information. Id. at 308–09.

In contrast, modern cell-site data is unlike a

bank statement. The “seismic shifts in digital technology” made it possible to track “not only Carpenter’s location but also everyone else’s, not for a short

period but for years and years.” Id. at 313. Even in

dissent, the point drew agreement: the new investigative tools “may have the potential to upset traditional privacy expectations.” Id. at 338 (Kennedy, J.,

dissenting). Extending the third-party doctrine to

those records would give the government an account

of a person’s movements that earlier cases had never

contemplated. There is “a world of difference” between the limited information addressed in those

cases and the “exhaustive chronicle of location information casually collected by wireless carriers today.” Id. at 314 (majority op.).

The Court thus again recognized that constitutional protections must be considered in light of the

power and scope of modern technology. Earlier cases

arose in an era where “few could have imagined a

society in which a phone goes wherever its owner

goes,” continually generating “a detailed and comprehensive record of the person’s movements.” Id. at

309. The relevant question was not whether old doctrine had ceased to matter, but whether its premises

still fit.

7

The ability to assemble cell-site data records

changed what the government could learn from

them. It would be “wrong to assume that contemporary databases are simply the younger siblings” of

their analog predecessors; older systems could not

“automatically sift through huge volumes of standardized material.” Erin Murphy, Databases, Doctrine, and Constitutional Criminal Procedure, 37

Fordham Urb. L.J. 803, 807 (2010). Cell-site data,

by comparison, could be mined, organized, and reproduced to reconstruct a person’s movements. Applying precedent required attention to that capability, not just to who held the records. The inquiry

must account for “not only the qualitatively distinct

features of the information, but also the type of policing involved in obtaining it.” Elizabeth E. Joh, Artificial Intelligence and Policing: Hints in the Carpenter Decision, 16 Ohio St. J. Crim. L. 281, 290 (2018).

That “recognition of digital transformation” served

“to ensure that the Fourth Amendment protects the

digital lives of citizens.”2

Modern technology also undermined the premise

that a person who conveys information to another

has chosen to expose it. Carrying a cell phone is “indispensable to participation in modern society,” and

the device generates location information “without

any affirmative act on the part of the user beyond

powering up.” Carpenter, 585 U.S. at 315. A person

does not meaningfully choose to disclose a comprehensive record of their movements simply by using a

2 Andrew

Guthrie Ferguson, Future-Proofing the Fourth

Amendment, Harv. L. Rev. Blog (June 25, 2018),

https://perma.cc/4583-3KFR.

8

phone. Id. at 315–16. And the implications extend

well beyond location records: “Today we use the Internet to do most everything,” including storing materials “we would have locked safely in a desk drawer or destroyed” in an earlier era. Id. at 387 (Gorsuch, J., dissenting). If doctrine treated that shift as

a surrender of privacy, “our Fourth Amendment

rights [would be] reduced to nearly nothing.” Id.

Fourth Amendment protection remains constant; its

application must account for the world in which people now live.

3. This past Term, the Court in Chatrie again rejected the mechanical application of analog Fourth

Amendment rules to digital rummaging. Police used

a geofence warrant to obtain Location History data

identifying phones near the scene of a bank robbery.

Chatrie, 146 S. Ct. at 2199–2202. The Government

argued the Fourth Amendment was not implicated

because, unlike Carpenter, the records covered a

short period, and the Location History was generated after a user affirmatively enabled the service.

But in Chatrie, as in Riley and Carpenter, the

Court rejected this myopic view. Instead, the Court

focused on what the technology exposed and how the

Fourth Amendment protected it. Carpenter’s guideposts help “to establish the purpose of the Fourth

Amendment, what it protects, how it protects, and

how it evolves.” Andrew Guthrie Ferguson, Digital

Policing After Chatrie 5 (July 24, 2026) (forthcoming). As “innovations” expand “the Government’s

capacity to encroach upon areas normally guarded

from inquisitive eyes,” courts must account for that

increased power. Chatrie, 146 S. Ct. at 2205–06

(quotation omitted). Location History is more pre-

9

cise and revealing than the data at issue in Carpenter, capable of allowing “tireless and absolute surveillance” of people and places with little effort. Id.

at 2207–09 (quotation omitted). The Government’s

reading “narrowed Carpenter to [cell-site] technology

and opened the door to numerous other warrantless

tracking surveillance systems.” Ferguson, Digital

Policing After Chatrie, supra, at 2. Everything Carpenter relied on “applies as well or better” to Location History. Chatrie, 146 S. Ct. at 2207–08. But

the Court did not alter the Fourth Amendment to

meet new technology. Instead, it applied the existing protection to reflect the greater intrusion technology made possible.

The Court also recognized the holistic nature of

digital life.

Fourth Amendment protections for

smartphone use cannot be divided—an “app-by-app,

feature-by-feature method of granting Fourth

Amendment protection misapprehends the very nature of modern cell-phone use.” Id. at 2214. Unlike

a briefcase, whose contents reflect what a person

chooses to carry on a particular day, a smartphone

brings together information accumulated across a

person’s life, whether a particular record is accessed

daily, rarely, or not at all. Fourth Amendment protection cannot turn on which app or service produced

the information, or whether a user opted-in, clicked

through a terms of service agreement, or toggled on

or off a particular feature. Id. Nor does it wait until

an intrusion “goes too far.” Id. at 2210 (quotation

omitted).

*

*

*

10

These decisions demonstrate the basic principle

applicable to the Court’s approach to the Fourth

Amendment and new technology: Courts must examine how enduring principles underlying the Fourth

Amendment apply to the reality of the digital search

at issue.3 The nature of the information, scale of the

intrusion, and role of technology in daily life bear on

that inquiry.

Because ultimately, “[w]here the

Fourth Amendment applies, it applies," whatever

“the quality or quantity of information” it obtains.

Chatrie, 146 S. Ct. at 2210 (quoting Kyllo, 533 U.S.

at 37). The technology may be new, but the constitutional principle is not.

II. THE BORDER EXCEPTION CANNOT AND

SHOULD NOT APPLY TO CELL PHONE

SEARCHES.

A. The Logic Of The Border Exception Is

Fundamentally Rooted In The Physical

World.

The border exception permits searches to control

the physical entry of people and goods.

It is

“grounded in the recognized right of the sovereign to

control, subject to substantive limitations imposed

by the Constitution, who and what may enter the

3 The cases address different stages of the Fourth Amend-

ment analysis. Riley examined whether the warrant requirement gave way to an exception, while Carpenter and Chatrie

addressed whether the conduct triggered a reasonable expectation of privacy at all. But the same reasoning runs through

each case: the Court considers the realities of the technology in

applying enduring Fourth Amendment protections to ensure

that “the rule the Court adopts . . . take[s] account of more sophisticated systems that are already in use or in development.”

Carpenter, 585 U.S. at 313 (quotation omitted).

11

country.” United States v. Ramsey, 431 U.S. 606,

620 (1977). That authority serves concrete purposes:

enforcing customs and importation laws, administering immigration laws, and stopping contraband at

the border. See, e.g., Orin Kerr, The Digital Fourth

Amendment: Privacy and Policing in Our Online

World 123 (2025). Those purposes are tied to the

unique character of a border entry, which brings a

person or item within the government’s power to determine whether entry is lawful. For that reason,

“from before the adoption of the Fourth Amendment,” border searches “have been considered ‘reasonable’ by the single fact that the person or item in

question had entered into our country from outside.”

Ramsey, 431 U.S. at 619. But this physical logic

does not extend to border searches in the digital

world.

B. The Logic Of The Border Exception

Does Not Translate To The Digital

World.

Unlike the contents of one’s pockets or backpack,

digital data need not pass through a physical checkpoint to enter the country. In border-exception cases, the border serves as a choke point for the movement of tangible objects—a moment where authorities can intercept prohibited goods before they enter

and disappear into the country. See, e.g., United

States v. Flores-Montano, 541 U.S. 149, 152 (2004)

(drugs secreted in fuel tanks); United States v. Montoya de Hernandez, 473 U.S. 531, 537 (1985) (contraband). Cell phones and the digital data they carry defy this logic entirely. A physical checkpoint

cannot prevent the same data from arriving by other

means. The contrast is clear: The gas tank in Flo-

12

res-Montano could conceal physical contraband; the

traveler in Montoya de Hernandez could carry drugs

inside her body. In each case, the checkpoint gave

the government a unique opportunity to intercept a

tangible object before it entered the country. But

stopping a device at the border will not stop the information available through it from reaching the

United States.

The location of the search has correspondingly

little connection to the government’s interest in the

data. Unlike drugs, weapons, or prohibited agricultural products, data does not “enter” the United

States in any meaningful sense simply because a device storing one copy of it crosses the border. The

same data may already be accessible inside the

country, or it may be transmitted there without the

traveler or the traveler’s phone. Searching that

phone may uncover evidence, but the crossing does

not give the government the distinctive opportunity

to prevent physical entry that justified the searches

in the border cases. An interest in obtaining the information does not itself explain why the government must obtain it without a warrant at that particular place.

That mismatch limits the weight of the government’s asserted border interest. The exception addresses the entry of people and physical goods; digital searches are a poor fit for catching and preventing the physical kinds of national security harms

that the border exception was designed to address.

The Fourth Amendment requires justification for

dispensing with its ordinary protections, and the

physical border alone does not supply one for every

digital search. Extending the border exception re-

13

quires courts to explain how its purposes justify the

intrusion into the data itself.4

C. Comparing The Diminished Government Interest In A Warrantless Search

To The Immense Intrusion On Privacy,

The Border Exception As Applied To

Digital Devices Searches Is Unreasonable.

Against the government’s diminished border interest stands a far greater intrusion into a traveler’s

private life. Digital devices hold “the privacies of

life,” distinct from a simple collection of objects in a

traveler’s luggage. Riley, 573 U.S. at 403 (quoting

Boyd v. United States, 116 U.S. 616, 630 (1886)).

The constitutional balance must account for that difference, just as it did when the rationales for a

search incident to arrest failed to justify access to

phone data. Id. at 385–86. Where the privacy intrusion is minimal—as with a cursory inspection of luggage or physical-object searches previously discussed—the government’s sovereign interest in protecting its borders may suffice to justify a search

4 In

this way digital data also upends the balancing test

that undergirds the border exception. See Montoya de Hernandez, 473 U.S. at 539-40 (weighing government interest against

individual privacy). The border exception traditionally passes

this test because the government’s interest is at its “zenith”

when protecting the border. Flores-Montano, 541 U.S. at 152

(citing Ramsey, 431 U.S. at 616). But the sovereign interest

that justifies dispensing with a warrant requirement for a

physical search cannot transition to digital devices. Because a

device search is ineffective at stopping data from crossing the

border, and poses a severe privacy intrusion, the balancing test

fails.

14

without individualized suspicion. But where the intrusion reaches into the most intimate and expansive corners of a massive repository of a person’s life,

that balance shifts dramatically. Digital data is

fundamentally different, so a digital search at the

border implicates privacy interests of an entirely different magnitude. Several features of that search

show why the balance cannot simply be carried over

from physical objects.

1. First, a phone exposes an archive no traveler

could carry in a suitcase. Even in 2014, cell phones

had “immense storage capacity” sufficient to hold

“millions of pages of text, thousands of pictures, or

hundreds of videos.” Riley, 573 U.S. at 393–94. A

border agent searching a suitcase might find a couple of letters, a photo album, or a personal diary.

The same agent searching a digital device can rummage through decades of correspondence, a lifetime

of personal photographs, comprehensive financial

records, and detailed medical information. After all,

what was once committed to paper is now “less and

less likely to be found in physical forms” and lives

instead in “the bits and bytes of an iPhone, Flickr

account, or Gmail calendar server.” Erin Murphy,

The Politics of Privacy in the Criminal Justice System: Information Disclosure, the Fourth Amendment,

and Statutory Law Enforcement Exemptions, 111

Mich. L. Rev. 485, 488 (2013). The volume of this

material is “exponentially more revealing than anything that might have been carried on a person before.” Ferguson, Why Digital Policing Is Different,

supra, at 833. The intrusion also grows when different records are read together: they “reveal much

more in combination than any isolated record.” Ri-

15

ley, 573 U.S. at 394. A location record, a message,

and a payment may together reveal a relationship or

activity that none discloses alone.

Nor does carrying a phone reflect a real decision

by the traveler to bring each of those records across

the border. A traveler selects which financial documents to put in a briefcase or which medical records

to pack in a purse. Leaving the rest at home or in an

office keeps them outside the purview of a luggage

search. Digital devices work differently: their usefulness depends on access to information accumulated over time, much of it unrelated to the journey.

Travelers do not selectively pack data as they pack

their bags. They expect it to remain shielded from

the government’s “inquisitive eyes” while using the

device that makes it available. See Chatrie, 146 S.

Ct. at 2209 (quotation omitted). Possession of a device cannot reasonably be treated as a choice to expose everything it can retrieve.

Even if it were feasible to carry hard copies of

information this voluminous and this sensitive, no

reasonable traveler would take that risk: A briefcase

full of financial documents, a purse full of medical

records, or a bag full of every client’s complete file

feels far more exposed—and far more unreasonable

to travel with—than a cell phone in one’s pocket.

Nor is a phone that allows “offloading” of data practical. “The point of carrying smartphones is to use

what is on them.” Chatrie, 146 S. Ct. at 2214. The

apps and “services they provide” are what have become a “pervasive and insistent”—even “indispensable”—“part of daily life.” Id. (quotation omitted).

Travelers use the same device to get to the airport,

check in for a flight, pay for a meal, speak with fami-

16

ly, join a client call, pull up a confidential work

memo, store personal honeymoon photos, and present a boarding pass. On arrival, they may use it to

navigate customs and immigration procedures, arrange transportation, and check into the hotel.5 The

apps that perform those tasks connect the traveler to

records and communications having nothing to do

with crossing the border, yet all may be exposed to a

border officer simply because the device was in the

traveler’s pocket. The convenience of carrying those

functions in one device does not diminish the privacy

of the information they make accessible.

2. Second, devices reveal categories of information that a traditional luggage search could not

assemble. Minute-by-minute location history can

reconstruct every “indisputably private” place its

owner has traveled, including trips “to the psychiatrist, the plastic surgeon, the abortion clinic, the

AIDS treatment center, the strip club, the criminal

defense attorney, or the by-the-hour motel.” Chatrie,

146 S. Ct. at 2210 (citing Jones, 565 U.S. at 415 (Sotomayor, J., concurring)). App data may store travelers’ biometrics, sleeping and eating patterns, romantic interests, and financial circumstances. None

of these categories could be discovered by rifling

5 See U.S. Customs & Border Prot., Mobile Passport Control

(MPC), https://www.cbp.gov/travel/us-citizens/mobile-passportcontrol (travelers can use CBP’s app rather than completing

paper Customs Declaration forms); see also U.S. Customs &

Border Prot., CBP Home Mobile App (allows aliens to notify the

U.S. Government of their intent to depart the United States),

https://www.cbp.gov/about/mobile-apps-directory/cbphome.

17

through the papers and objects in a suitcase at the

border, yet all may be exposed by a digital search.

Border agents inspecting luggage have never had access to this breadth of information. And while law

enforcement officers at the border—engaged, as they

are, “in the often competitive enterprise of ferreting

out crime,” Johnson v. United States, 333 U.S. 10, 14

(1948)—may surely desire it, data’s potential investigative value does not establish that the border exception authorizes warrantless and suspicionless access to it.

3. Third, a device gives access to information

that never accompanied the traveler at all. “‘Cloud

computing’ refers to the capacity of Internetconnected devices to display data stored on remote

servers rather than on the device itself,” and users

“often may not know whether particular information

is stored on the device or in the cloud.” Chatrie, 146

S. Ct. at 2201 (citing Riley, 573 U.S. at 397). Cloud

access can “shift our perceptions of what a single

source of data collection, storage, and analysis is.”

Joh, Artificial Intelligence and Policing, supra, at

289. A search through the phone may reach years of

records on those servers, expanding the quantity of

information available and the places from which it is

retrieved. The government’s search extends beyond

the traveler’s person and effects at the crossing, able

to capture a lifetime of digital existence. An exception grounded in physical entry cannot explain that

reach merely by pointing to the phone’s location.

4. Fourth, the search exposes people who never

crossed the border. Modern communication is inherently networked, and searching one traveler’s phone

can “expose embarrassing details on the target and

18

all of their contacts.” Andrew Guthrie Ferguson,

Digital Rummaging, 101 Wash. U. L. Rev. 1473,

1524–25 (2024). Those contacts may include people

who have never left the United States and have no

connection to the trip. A single device provides confidential information about business entities that

employ the traveler, or identities of the customers

and clients who have hired them. Their information

is exposed because someone else possesses it, not because they are “enter[ing] into our country from outside.” See Ramsey, 431 U.S. at 619. And as to that

larger universe of people whose privacy interests are

invaded despite being physically absent, the government’s asserted national-security interest in limiting physical contraband entering the country

crumbles.

Digital records can reveal a person’s “familial,

political, professional, religious, and sexual associations.” Jones, 565 U.S. at 415 (Sotomayor, J., concurring). Professional relationships can be particularly vulnerable. Anibowei’s phone held privileged

and confidential client communications, including

communications concerning people adverse to the

Department of Homeland Security. A journalist’s

phone may identify confidential sources. See, e.g.,

Bryan Sykes, Border Search Rationales Ripe for

Abuse, with Journalists Particularly at Risk, 45 Hastings Comm. & Ent. L.J. 165 (2023). A law clerk’s

phone might contain confidential materials related

to matters pending before a court. In each case,

searching one device compromises the web of confidences entrusted to its owner by many people with

no notice of the search.

5. Fifth, returning the phone does not end the

19

intrusion. Unlike the physical inspection of luggage—a discrete and localized event—copying a

phone’s contents, as happened to Anibowei, permits

continued examination after the device and its owner have gone. The government’s directives authorize

retention of certain extracted data for weeks without

probable cause. U.S. Customs & Border Prot. CBP

Directive No. 3340-049B, Border Search of Electronic

Devices 11 (Jan. 1, 2026). Once ingested into that

system, the traveler’s digital life is divorced from the

border entirely. The data can be shared with local,

state, and federal enforcement agencies. Id. The

search at the border is merely the collection phase of

a continuing intrusion. Stored data gives the government “the ability to search historically for suspicious activities not yet discovered.” Ferguson, Digital Rummaging, supra, at 1506.6 And it can reach

beyond the traveler, generating investigative targets

by revealing related data “from as yet unknown persons that indicate suspicious behavior”—all without

ever crossing the border themselves. Joh, Artificial

Intelligence and Policing, supra, at 285.

These features change both sides of the constitutional balance. The search can reach a lifetime of

records, draw information from remote locations, ex6 The technology needed for this kind of collection, storage,

and passive analysis is “remarkably easy, cheap, and efficient

compared to traditional investigative tools”, and requires “little

additional effort” from the police. See Joh, Artificial Intelligence and Policing, supra, at 288 (citing Carpenter, 585 U.S. at

311). Practical constraints matter to the Fourth Amendment

analysis; for example traditional long-term monitoring was less

invasive in part because it was “difficult and costly and therefore rarely undertaken.” Jones, 565 U.S. at 429 (Alito, J., concurring in the judgment).

20

pose the confidences of others, and permit examination long after the traveler returns home. Yet the

government’s justification remains an exception directed at controlling the physical entry of people and

goods. The Fourth Amendment requires courts to

test that rationale against the search the government actually seeks to conduct, and the consequences of that search on its subject. See Riley, 573 U.S.

at 385–86. A phone’s passage across the border does

not resolve that mismatch or explain why the “privacies of life” lose their protection there. Chatrie, 146

S. Ct. at 2205 (citing Boyd, 116 U.S. at 630; Carpenter, 585 U.S. at 305). A rule designed to inspect persons and physical goods cannot justify access to a

traveler’s entire digital life merely because the

phone crosses the border.

III. THE COURT SHOULD RESOLVE THE

QUESTION PRESENTED NOW.

Even beyond the circuit conflict described in the

Petition, certiorari is further warranted because the

decision below imposes substantial burdens on thousands of travelers who cross our borders every day.

As a practical matter, there is no way for a traveler

to avoid the consequences of the court of appeals’ decision. Courts have noted that travelers “are free to

leave any property they do not want searched . . . at

home.” United States v. Touset, 890 F.3d 1227, 1235

(11th Cir. 2018). But that is no answer in the wake

of the digital shift recognized in Riley and Carpenter.

A traveler can decide to leave a diary or a set of documents behind, but “the same is not true, at least

practically speaking, when it comes to smartphones

and digital devices.” United States v. Kolsuz, 890

F.3d 133, 145 (4th Cir. 2018).

21

Nor can travelers reliably protect sensitive information on the phone itself. Fourth Amendment

doctrine offers “little basis to distinguish between

behavior that legitimately invites police suspicion

and that which should be left alone because it might

protest the surveillance itself.” Elizabeth E. Joh,

Privacy Protests: Surveillance Evasion and Fourth

Amendment Suspicion, 55 Ariz. L. Rev. 997, 1017

(2013). So measures intended to shield private files

may instead invite further scrutiny. At the border,

mere password protection itself has been treated as

a factor supporting a warrantless search. See id. at

1027 n.185 (noting United States v. Cotterman, 709

F.3d 952, 969 (9th Cir. 2013), “permit[ed the] use of

password-protected file as part of [the] reasonable

basis analysis”). A choice between leaving private

information exposed and taking precautions that

may justify a deeper search is no choice at all. It also renders the millions of people who cross borders

for personal and professional reasons vulnerable to

having their entire digital life exposed based on the

arbitrary whim of a border agent.7

Anibowei’s experience crystallizes that dilemma.

CBP copied the contents of his work phone in 2016,

and border agents have searched his phone at least

four more times since. Anibowei v. Bondi, 2025 WL

3231720, at *1 (5th Cir. Nov. 19, 2025). As an immi7 See, e.g., Gaya Gupta & Angie Orellana Hernandez, Bor-

der Agents Ask Lawyer With Pro-Palestinian Client to Give Up

Phone,

Wash.

Post

(Apr.

8,

2025),

https://www.washingtonpost.com/2025/04/08/michigan-lawyerborder-phone/ (border agents demanded access to a lawyer’s

phone despite objection that it contained privileged client information).

22

gration lawyer, he relies on communications, contacts, and files concerning clients whose interests

may be adverse to the very agency conducting the

search. Leaving the phone behind impairs that work

and his duty to those clients; bringing it exposes the

information entrusted to him and imperils his duty

of confidentiality. He faces that untenable choice

each time he travels.8

And his clients have no choice at all. They cannot control what their lawyer carries abroad, any

more than patients, sources, parents, or colleagues

can control what a doctor, journalist, child, or employee takes on a trip. The same is true of anyone

whose messages, photographs, or shared files appear

on another person’s device. A search can expose “innocent people who simply communicated with” the

device’s owner. Ferguson, Digital Rummaging, supra, at 1525. For those people, leaving a device at

home accomplishes nothing.

Chatrie makes review especially timely. It confirms that courts must assess whether the rationales

for established doctrine fit the digital intrusion before them. Here, that legal question determines the

validity of nationwide federal directives governing

an ever-growing number of searches. CBP reported

8 A

burner or “clean” phone offers no solution. Burner

phones may “protect privacy,” but they are “cumbersome to

use” compared with phones connected to the services their

owners rely on. Joh, Privacy Protests, supra, at 1012. A lawyer

who removes access to client files cannot work from the road. A

business traveler who removes corporate applications and authentication tools may not be able to work at all. A strippeddown phone protects privacy only by sacrificing the reason for

carrying it.

23

searching the electronic devices of 8,503 arriving international travelers in fiscal year 2015 and 55,318

in fiscal year 2025.9 More than nine in ten Americans now carry a smartphone. Chatrie, 146 S. Ct. at

2200. Each day this question remains unresolved

brings further searches of devices on which ordinary

travelers depend.

This case presents the question directly. The

Fifth Circuit agreed that the validity of the challenged directives “turns squarely and solely” on

whether the Fourth Amendment generally requires

warrants to search cell phones at the border. Anibowei, 2025 WL 3231720, at *2 (emphasis and quotation omitted). Nationwide, the courts of appeals

disagree over the permissible scope of cell-phone

searches at the border. See, e.g., United States v.

Alisigwe, No. 24-960, slip op. at 5 (2d Cir. Sept. 17,

2026) (no warrant or suspicion required, treating

cellphones like physical property); United States v.

Cano, 934 F.3d 1002, 1018 (9th Cir. 2019) (depends

on “whether the phone contains contraband”);

Alasaad v. Mayorkas, 988 F.3d 8, 21 (1st Cir. 2021)

(requiring “evidence of activity in violation of the

laws enforced or administered by CBP or ICE”). The

upshot is that travelers’ Fourth Amendment’s protections vary based on whether they fly into LAX,

JFK, or Logan. This Court should grant certiorari to

9 U.S. Customs & Border Prot., CBP Releases Statistics on

Electronic

Device

Searches

(Apr.

11,

2017),

https://www.cbp.gov/newsroom/national-media-release/cbpreleases-statistics-electronic-device-searches-0; U.S. Customs &

Border Prot., Border Search of Electronic Devices at Ports of

Entry (updated Aug. 4, 2026), https://www.cbp.gov/travel/dbpsearch-authority/border-search-electronic-devices.

24

provide the single, nationwide answer that travelers

and border agents all need and the Fourth Amendment demands.

CONCLUSION

The Court should grant certiorari to uphold the

Fourth Amendment’s protections.

Respectfully submitted,

ANTON METLITSKY

(Counsel of Record)

O’MELVENY & MYERS LLP

1301 Ave. of the Americas

17th Floor

New York, NY 10019

(212) 326-2000

ametlitsky@omm.com

TIMUR AKMAN-DUFFY

GILLIAN MAK

O’MELVENY & MYERS LLP

1625 Eye Street, N.W.

Washington, D.C. 20006

Attorneys for Amici Curiae

September 18, 2026