Courts & Litigation Criminal Justice & the Rule of Law Surveillance & Privacy

Smart Phones at the Border: What Does the Fourth Amendment Protect?

Jacob Pagano
Wednesday, September 20, 2023, 2:19 PM
The circuit courts’ split grows more pressing after a district court decision requires warrants for cell phone searches at the border.
The U.S. Customs and Border Patrol facility at Stewart Airport in New York, May 2021. (The Port Authority of New York and New Jersey,; CC BY-NC-ND 2.0,

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When Jatiek Smith arrived at Newark airport on a flight from Jamaica in March 2021, agents with Customs and Border Protection (CBP) processed a request from the FBI to search Smith, whom the FBI was investigating for possible participation in a conspiracy to submit fraudulent insurance claims, among other offenses. The agents, without obtaining a warrant, seized Smith’s phone and conducted a manual search, reviewing the phone’s text messages and then saving a copy of the phone’s data.

In a nonborder setting, the agents would have needed a warrant. As the Supreme Court made clear in Riley v. California, the Fourth Amendment provides individuals a heightened expectation of privacy in cell phones, which “differ in both a quantitative and a qualitative sense” from other items due to the immense amount of personal data they contain. Thus, warrants are generally required to search them, even when an individual is being placed under arrest. But here, the agents cited a well-known exception to that rule—the border exception, which presumes that border searches, including any de facto port of entry to the United States (such as an airport), are reasonable. Indeed, under the guiding law of both the First and Eleventh Circuits, no warrant would be needed to search Smith’s phone. The fact that the border agents made the search pursuant to their “border search authority” would place them in compliance with Fourth Amendment law.

But in a detailed opinion issued on May 11, Judge Jed Rakoff in the U.S. District Court for the Southern District of New York concluded otherwise, asserting that the aforementioned circuit courts have understated the Riley holding and overstated the border exception. Specifically, he held that, for searches of cell phones at the border, agents first need to obtain a warrant (Rakoff ultimately held the evidence on Smith’s phone admissible, because the agents subsequently obtained a warrant after the warrantless search). Rakoff’s holding, which notes an exception to the warrant rule for exigent circumstances and does not address whether the warrant rule extends to nonresidents or noncitizens, throws into relief a complex circuit split on the proper meaning of the Fourth Amendment’s border exception with respect to cell phones. Notably, the opinion adopts a rule similar to that suggested in proposed legislation from 2019, the Protecting Data at the Border Act, which would require agents to first obtain a warrant before searching the electronic device of a “United States person” at the border. 

The range of views among the circuits and district courts on the Fourth Amendment’s meaning with respect to cell phones at the border is notable: While some circuits have applied the border exception whole-cloth to cell phones, several district courts, including the District of Columbia, have disagreed and required that agents have at least a reasonable, individualized suspicion before conducting a forensic cell phone search. But none has required a warrant as in Smith, a holding that could have notable implications for border agents, who routinely conduct warrantless searches of cell phones on tips from law enforcement. (Consider, for example, the May 2023 Eighth Circuit decision in U.S. v. Haitao Xiang, where border agents at Chicago’s O’Hare airport used information from local FBI agents as a basis for searching the cell phone of Xiang, a Chinese national suspected of stealing and attempting to export secrets from Monsanto, a U.S. agrochemical corporation, in violation of the Espionage Act.)

Controversy around border searches of cell phones is not new. In a 2018 Lawfare piece, Grayson Clary focused on the Eleventh Circuit opinion in United States v. Touset, in which Judge Jill Pryor concluded that neither reasonable suspicion, nor a warrant, was required to justify a forensic search of an individual’s cell phone at the border.

At least four notable opinions on the question—including from the First, Fourth, Eighth, and Ninth Circuits—have complicated the picture. Two questions are at the crux of the split. First is a dispute over whether reasonable suspicion is needed to justify a forensic search of an electronic device. The second concerns the permissible scope of a warrantless border search, a question on which the circuits are all over the map. Whereas the Ninth Circuit would limit warrantless searches to digital contraband, or data that is itself illegal to possess, the First Circuit would allow warrantless searches to extend to evidence of contraband as well as “evidence of activity in violation of the laws enforced or administered by CBP or ICE [Immigration and Customs Enforcement].” The Fourth Circuit adopts a similar approach to the First Circuit, requiring searches to be limited to evidence of an ongoing border violation, but would not permit searches of generalized border crimes, such as evidence on a cell phone of a past or future border violation.

What follows is an outline of the relevant precedent, a survey of the split (including Judge Rakoff’s notable opinion), and a brief argument that the Fourth Circuit’s approach—which recognizes that warrantless border searches extend to evidence of ongoing border-related offenses, as well as evidence of digital contraband itself—balances best the state interests in the border exception with the core holding of Riley.

The Fourth Amendment and the Border Exception

The Fourth Amendment provides “[t]he right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no warrants shall issue, but upon probable cause” As the Supreme Court has long maintained, “reasonableness generally requires the obtaining of a judicial warrant.” 

A major exception to the general warrant requirement is the border exception, which recognizes the sovereign authority of Congress and the executive to conduct searches at the border, for persons and property, whether coming into or going out of the country. Thus, border searches “are reasonable simply by virtue of the fact that they occur at the border.” But there are limits. For example, the government typically must demonstrate a reasonable suspicion—generally, an individualized suspicionwhen it seeks to conduct a nonroutine search. Specifically, the Supreme Court ruled, in U.S. v. Montoya de Hernandez, that the government must demonstrate an individualized suspicion before an individual can be detained for observation, such as to monitor whether that individual has smuggled drugs. Further, the Second Circuit requires reasonable suspicion to conduct strip searches. With some exceptions, such as the Eleventh Circuit’s Touset decision, the circuits generally agree that, for forensic cell phone searches, reasonable suspicion must be shown. The reasonable suspicion standard, however, is likely to be met in most instances where agents either receive a law enforcement tip or obtain incriminating evidence from a manual search of the individual’s person or baggage, or the individual’s cell phone, at the border. 

The border exception received renewed attention in the wake of Sept. 11, as national security-based border searches became more common. Notably, the Supreme Court held in 2004 that “the Government’s interest in preventing the entry of unwanted persons and effects is at its zenith at the international border.” But the terrain has since become more muddled, as two recent Supreme Court decisions—most notably Riley and Carpenter v. United Statesraised new questions for the scope of the exception and the Fourth Amendment’s proper scope in the digital era. Of these two decisions, Riley is most relevant here.

Riley Recognizes a Heightened Privacy Interest in Cell Phones

Riley made clear that cell phones, or what the Court called “minicomputers,” are sui generis for Fourth Amendment purposes. Specifically, the Court held that the widely recognized search incident to arrest exception, which allows police officers to search the physical person of an individual placed under arrest, does not extend to cell phones. In doing so, the Court balanced the interests of the state in promptly obtaining the information contained in the arrestee’s cell phone with the individual’s privacy interest. Writing for the Court, Justice John Roberts explained that a search of an individual’s cell phone did not meaningfully advance the purposes of the search incident to arrest exception—officer safety and the preservation of evidence. Meanwhile, a cell search undermined an extremely significant privacy interest by encroaching on a vast digital domain that differed “in both a quantitative and a qualitative sense” from the information the police officers might find in someone’s pockets or briefcase. Thus the individual’s privacy interest was weightier than the state’s search interest.

The question remains, however, whether Riley dictates that cell phones receive heightened protection at the border in general.

U.S. v. Smith and the Warrant Requirement

In Smith, Judge Rakoff applied the balancing test from Riley and concluded that the privacy interest outweighed the state’s at the border. The opinion was not surprising for its emphasis on the individual’s right to privacy on his cell phone, a holding that comes straight from Riley. What is surprising, however, is the decision’s determination that “[n]one of the rationales supporting the border search exception justifies applying it to searches of digital information contained on a traveler’s cell phone.” Rakoff outlined those interests, citing border integrity and preventing entrants who may “bring anything harmful.” But the searching of a cell phone, Rakoff held, does not advance the purposes of the border exception because it prevents “a person or thing outside the country from unlawfully coming into it.”

Rakoff justified this holding on the ground that digital data often does not exist only within the cell phone. Rather, it often exists in the “cloud,” stored on a server that is potentially thousands of miles away and already in the U.S. “Stopping the cell phone from entering the country would not, in other words, mean stopping the data contained on it from entering the country,” he wrote.

This technical view of the cell phone data’s locus, advanced by Orin Kerr (Kerr also argues, in a 2013 piece, that the Court should adopt the Gant standard used to justify automobile searches and apply it to cell phone searches at the border, allowing such searches when it “is reasonable to believe evidence relevant to the crime of arrest might be found [in the phone]”), seems at odds with the border exception’s purpose. For one, Rakoff assumes that “digital data exists separate and apart from the physical cell phone on which it is stored.” That could be the case, but it is not always so (indeed, an individual could have just stored data on their phone, and not used cloud services). Second, even if the data is not on the phone, and so not being stopped by being searched, the phone itself is the most immediately logical connection to the data. Finally, it seems odd to say that the border exception would not be served by stopping harmful data—whether it is a border violation to carry that data or digital contraband—from entering the country. Even if the data is both on the phone and on a server, seizing it at the border would have the effect of stopping that individual from coming into the country with it.

Rakoff’s opinion is valuable for the weight it places on the individual’s privacy interest in his cell phone, but it underemphasizes the full scope of the government’s interest in the border exception. Further, the opinion’s warrant requirement would reconfigure the authority of border agents to conduct searches in ways that could undermine the expediency demanded at border points.

No circuit that has addressed this issue adopted the Smith approach of mapping the Riley warrant requirement to cell phones at the border. For the First Circuit, for example, Judge Sandra Lynch held in Alasaad v. Mayorkas that Riley does not, “by its own terms apply to border searches, which are entirely separate from the search incident to arrest searches discussed in Riley.” The dispute only begins at this point, however. Even assuming that Riley does not protect the cell phone from warrantless search at the border, the question remains: Absent a warrant, what kind of information can border agents obtain at the border, without running afoul of the Fourth Amendment?

The Anything Harmful Approach

In Alasaad, the court rejected the plaintiffs’ civil action challenging CBP Directive No. 3340-049A and ICE Directive No. 7-6.1, both of which permit border agents to search electronic devices without a warrant, though they require reasonable suspicion before border agents can conduct an “advanced search,” which includes connecting a device to a hard drive to download its data. For either type of search, the scope is broad: The digital information need not be “digital contraband.” Rather, the First Circuit cabins the purview of the search to three categories: searches “for contraband, evidence of contraband, or for evidence of activity in violation of the laws enforced or administered by CBP or ICE.” Judge Lynch justified this holding, pointing to the border exception’s overarching purpose of preventing “anything harmful” from entering the country, and concluded that “Congress is better situated than the judiciary to identify the harms that threaten us at the border,” an approach adopted by Judge J. Harvie Wilkinson in his concurrence in U.S. v. Kolsuz.

The Eleventh Circuit adopted a similar approach in Touset, holding that border agents could conduct a forensic search of an individual’s cell phone at the border without showing reasonable or individualized suspicion. The court relied in part on two founding-era statutes, including several pieces of legislation passed in 1789, which provided for administering customs tariffs, and the Tariff Act of 1790, which allowed customs agents to search vessels before they arrived in the U.S. Judge Pryor concluded that the lack of a reasonable suspicion requirement in that statute evidenced the framers’ view of a capacious border search exception.

Similarly, in Haitao Xiang, the Eighth Circuit evidenced a favorable view of the Eleventh Circuit approach and upheld a forensic search of Xiang’s phone upon his egress from the U.S. to China. The court held that CBP had reasonable suspicion to search Xiang’s device—specifically, Xiang had just resigned from Monsanto and was traveling on a one-way ticket to China to work at an agricultural company, and CBP had tips from the FBI that Xiang, while at Monsanto, developed plans to give second-company documents to a third party overseas. The Eighth Circuit did not resolve the question as to whether the search must be connected to a border violation, as there was a clear border search justification: Agents suspected Xiang of violating the Economic Espionage Act of 1996.

The Digital Contraband Approach 

In U.S. v. Cano, the Ninth Circuit adopted a more limited view of the border exception, holding that warrantless searches of cell phones at the border were permissible only when the search was for digital contraband. “The border search exception authorizes warrantless searches of a cell phone only to determine whether the phone contains contraband,” Judge Jay Bybee wrote. Digital contraband, under Cano, refers to material that is itself illegal to possess. The court explained that “the detection-of-contraband justification would rarely seem to apply to an electronic search of a cell phone outside the context of child pornography.”

The digital contraband standard can lead to oddities in application, including in Cano itself, where border agents searched Miguel Cano’s car at an entry point in Tijuana after a detection dog alerted the agents. An agent obtained his phone and scrolled through his text messages. For the Ninth Circuit, the agent acted properly in this “manual search.” But the agent then took further action, recording phone numbers in Cano’s call log. The Ninth Circuit held that the border agents went too far in copying the phone numbers. “Those actions,” the court wrote, “have no connection whatsoever to digital contraband.” As the court explained, text messages could contain illegal images, whereas phone numbers in the call log could not constitute illegal contraband, even if connected to or used in a border violation. 

The Ninth Circuit’s opinion attempts to translate the border exception to the digital space. Most important to the opinion is a doctrinal distinction, articulated in Boydv. U.S., between items that are illegal to bring across the border, or goods on which a tariff is due, and evidence that is relevant to the prosecution of crimes, including future border crimes. The distinction was further emphasized by the Fifth Circuit in U.S. v. Molina-Isidoro, in which Judge Gregg Costa, in a special concurrence, emphasized that the Supreme Court “draws a sharp distinction between searches for contraband and those for evidence that may reveal the importation of contraband.”

On balance, the Ninth Circuit’s approach of limiting digital contraband to material that is itself illegal seems overly restrictive, especially because it (as the Ninth Circuit concedes) effectively limits the warrantless search at the border to images of sexual abuse. That seems illogical, not only because the primary state interest at many ports of entry is the detection of narcotics but also because digital material on the phone related to the border violation bears such a close relationship with the border violation itself that it should be subject to search.

The Fourth Circuit Strikes a Middle Ground

Finally, in Kolsuz, the Fourth Circuit adopted an approach similar to the First Circuit when it recognized that a warrantless electronic search extends to prevention of ongoing border-related crime, such as export of illegal firearms. Further, Judge Pamela Harris held that while manual searches can be conducted without any suspicion (falling squarely within the general border exception), particularized, reasonable suspicion is required for a forensic search. Harris also cautioned that in certain instances (not this case) “searches conducted under exceptions to the warrant requirement may require more than reasonable suspicion.” Here, however, reasonable suspicion was sufficient to justify a forensic search.

The facts here are important, likely indicative of many similar border search scenarios. In Kolsuz, the cell phone of Turkish citizen Hamza Kolsuz was searched when, upon his departure from Washington Dulles International Airport to Turkey, agents detected gun components in his bag. The agents’ manual search of his phone revealed evidence of text messages suggesting an illegal export scheme, and a forensic search revealed further incriminating evidence. Kolsuz was indicted for attempting to export firearms, among other offenses. Kolsuz argued that after his iPhone and firearm components were seized, a warrantless forensic search was unjustified because the purpose of the border exception—to prevent the ingress or egress of contraband—would not be furthered. Thus, “there was no contraband poised to exit the country and thus no nexus to that rationale.” This argument might succeed under the Ninth Circuit’s Cano decision, but it failed here. The court explained, however, that “[t]he justification behind the border search exception is broad enough to accommodate not only the direct interception of contraband as it crosses the border, but also the prevention and disruption of ongoing efforts to export contraband illegally, through searches initiated at the border.” 

The Fourth Circuit’s reading of the border exception likely aligns best with the exception’s purpose. At its core, the exception is designed to protect territorial sovereignty. The Fourth Circuit’s holding recognizes that digital material that bears a nexus with an ongoing, border-related crime is so intrinsically linked with the kind of material that border agents routinely intercept, such as contraband, that it should fall within the border exception. In short, if digital contraband itself is in the umbra of the kind of property the entry of which the border exception seeks to prevent, digital data concerning an ongoing border-related crime is firmly situated in the penumbra. Meanwhile, the Fourth Circuit holding does not extend the exception as far as the First Circuit, which allows searches of any material that might violate laws enforced by CBP, even if the violation is not ongoing—a standard that risks extending warrantless searches to a host of past or future offenses unconnected to an ongoing border-related crime. For searches of evidence concerning border violations that are not ongoing, or criminal activity more generally, a warrant is justified.

For now, for cell phones at the border, the split makes the classic law school answer the correct one: Whether agents can search, and what they can search without a warrant, depends (on the circuit you land in). To be sure, however, recent CBP policy suggests that border policy, in practice, requires reasonable, individualized suspicion for forensic cell phone searches.

Jacob Pagano is a student at Columbia Law School where he serves as a staff member on the Columbia Journal of Transnational Law and as a research assistant to Professor Kerrel Murray. He previously interned with Judge Timothy Reif at the US Court of International Trade and will join Covington & Burling in Los Angeles as a summer associate.

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