July 2023

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As many travelers know, federal agents at international borders have authority to search phones, computers, and other electronic devices.  Less clear, however, is whether agents may do so without a warrant, probable cause, or even reasonable suspicion.

The Fifth Circuit recently addressed that question, which falls “at the intersection of two established lines of Fourth Amendment precedent.”[1]  On one hand, border searches are typically deemed “reasonable simply by virtue of the fact that they occur at the border,” because the United States has a right to protect itself by “examining persons and property crossing into this country.”  On the other hand, though, “searches of modern devices like cell phones can be unusually intrusive.”

In United States v. Castillo, the Fifth Circuit joined several other circuits in holding that “no individualized suspicion is required for the government to undertake a manual border search of a cell phone.”[2]  In a brief seven-page opinion, the court left several other questions unanswered—including the precise contours of a “manual” search of a cell phone.   

I.  Electronic Devices

As technology has evolved, it has become difficult to apply old precedent to new facts.  Should a cell phone or a computer be treated like a file cabinet, a pay-phone booth, or something else entirely?  Courts have been grappling with these Fourth Amendment technological issues in a new way since at least 2014, when the Supreme Court decided Riley v. California.[3]  In Riley, the Court emphasized the unique nature of modern cell phones, which “differ in both a quantitative and a qualitative sense from other objects.”  “There are 396 million cell phone service accounts in the United States—for a Nation of 326 million people.”[4]  For many of those people, “it is no exaggeration to say [they] keep on their person a digital record of nearly every aspect of their lives—from the mundane to the intimate.”[5]  “Modern cell phones are not just another technological convenience. With all they contain and all they may reveal, they hold for many Americans the privacies of life.”[6]

For those reasons, in Riley, the Supreme Court’s “answer to the question of what police must do before searching a cell phone seized incident to an arrest” was “simple—get a warrant.”[7]  More recently, one district court applied Riley’s warrant requirement to border searches of electronic devices,[8] but that decision appears to be an outlier.  The federal circuit courts have been staking out positions at the other end of the spectrum, at least for “manual” searches.

II.  Limiting Principles

In Castillo, the Fifth Circuit distinguished “manual” and “forensic” searches[9] in two main ways: first, a manual search limits the quantity of information available to agents; and second, a manual search does not typically allow agents to see files that have been encrypted or deleted.[10]

Most modern cell phones, however, encrypt their contents behind a password, passcode, or facial recognition system.  In this case, the court had no reason to address compelled decryption because Castillo provided agents with the passcode to unlock his phone.  Imagine, however, a situation where Castillo had declined to unlock his phone.  It remains unclear whether agents could have required him (or any international traveler) to provide the password to allow them to conduct a manual search of his phone.[11]

Castillo also leaves travelers no certainty regarding more thorough forensic searches, which can permit long-term storage of a device’s contents.  Last year, Congress was told that the government maintains that data for 15 years.[12]  As noted, Castillo differentiated “manual” and “forensic” searches, leaving open the argument that forensic searches are fundamentally different and should require at least reasonable suspicion, if not probable cause or even a warrant.[13]

Finally, the Fifth Circuit did not identify any limits on agents’ ability to conduct a manual search.  Can they spend hours, or perhaps days, manually searching a person’s phone?  Can they retain the device to allow more thorough manual searching even after the traveler has left?  What if the device contains attorney-client, or sensitive business, information?  All those questions were left unanswered and may arise in future cases.

III.  Practically Speaking, What’s an International Traveler to Do?

If you are crossing an international border in the Fifth Circuit, whether getting off an international flight, exiting a cruise ship, or driving across the U.S.-Mexico border, the Castillo decision affects you.  You should evaluate what digital devices to take on your trip, knowing that agents have authority to open and manually search any of them.[14]  You (or your client) might consider the Washington Post’s guide entitled, “How to prevent customs agents from copying your phone’s content.”[15]

At the organization level, companies may want to create (or update) their policies and protocols for international travel.  It may be wise to encourage employees to save information to the company network, accessible only through VPN, rather than saving copies to their own devices, which might be searched during their travel.  Password protection should also be strongly encouraged, if not required.

Before traveling internationally, carefully consider your options and mitigate your risks. 

[1] United States v. Castillo, --- F.4th ---, No. 21-50406 (5th Cir. June 19, 2023).

[2] Id. at *2.

[3] 573 U.S. 373 (2014).

[4] Carpenter v. United States, 138 S. Ct. 2206 (2018).

[5] Riley, 573 U.S. at 395.

[6] Id. at 403.

[7] Id.

[8] United States v. Smith, No. 1:22-cr-00352-JSR (S.D.N.Y. May 11, 2023), available at https://s3.documentcloud.org/documents/23813619/us-v-smith.pdf.

[9] Loosely speaking, a forensic search occurs when agents connect an electronic device to a machine that can extract the full contents of the device, permitting agents to create a copy they can retain indefinitely and search comprehensively.

[10] Castillo, No. 21-50406, at *6.

[11] See generally Orin Kerr, Compelled Decryption and the Privilege Against Self-Incrimination, 97 Tex. L. Rev. 767 (2019).

[12] Drew Harwell, Customs officials have copied Americans’ phone data at massive scale (Sept. 15, 2022), The Washington Post, https://www.washingtonpost.com/technology/2022/09/15/government-surveillance-database-dhs/.

[13] But see Aisha J. Dennis, Riling Up the Border Search Doctrine: Litigating Searches of Digital Content at Our Ports of Entry, The Champion, March 2018 (the “dichotomy between ‘manual’ and ‘forensic’ searches is factually meaningless and constitutionally unworkable.  Constitutional rights should not turn on such a flimsy distinction.”) (quotation marks and citation omitted).

[14] U.S. Customs and Border Protection (“CBP”) reports that it searched the electronic devices of 45,499 travelers in fiscal year 2022.  CBP Enforcement Statistics, https://www.cbp.gov/newsroom/stats/cbp-enforcement-statistics.

[15] Tatum Hunter, How to prevent customs agents from copying your phone’s contents (Sept. 18, 2022), The Washington Post,  https://www.washingtonpost.com/technology/2022/09/18/phone-data-privacy-customs/.

KHALIL & LAKE is a white-collar litigation boutique focusing on federal criminal law, appeals, and complex investigations in a variety of business sectors. If you have any questions about these issues, or if you would like a copy of any materials mentioned here, please let us know.