And why I believe they are mistaken, and why the Supreme Court must weigh in.
Over the past decade, lower courts have wrestled with how the Fourth Amendment should apply when border authorities search digital devices like smartphones. The traditional justification for searching physical items crossing the border—protecting sovereign interests such as stopping contraband, enforcing immigration rules, and ensuring tariffs are collected—may not automatically extend to the digital realm. So, should government agents be allowed to search a traveler’s phone without any limits simply because the person is crossing an international boundary? Or should a warrant be required, or at least some reasonable suspicion?
My position is that these government interests are not furthered by digital searches, and that a warrant should be necessary to inspect a cell phone at the border, at least when the device belongs to a U.S. citizen. In The Digital Fourth Amendment, I draw a parallel to Riley v. California, the decision holding that the search-incident-to-arrest exception does not apply to cell phones. As in Riley, the tangible-world justifications for the border search rule do not translate neatly to the digital setting. Any extension of that rule to cell phones must stand on its own merits, which I do not believe it can.
Consider the practicalities. You can’t conceal a person inside a phone, and the information stored on a device isn’t subject to tariffs. While there is a concern about digital contraband—such as CSAM, or child sexual abuse material—the border search of digital devices is not conducted for that purpose. In practice, border searches of phones at entry are performed for everyday criminal enforcement aims. The goal is to identify wrongdoing, not to prevent contraband from entering the country. The border search power is leveraged at the border because phones, when combined with traditional border powers, provide a substantial tool for catching criminals. I contend the Fourth Amendment should not permit that windfall, given that these searches are undertaken for routine criminal enforcement rather than the sovereign interests that underpin the border-search exception. Consequently, I argue that a warrant is required, at least for searches of citizens’ devices. For those seeking the specifics of my argument, the SSRN chapter of The Digital Fourth Amendment lays out the details.
Yesterday, however, the Second Circuit disagreed. In United States v. Alisigwe, the court (led by Judge Menashi) held that no warrant—and not even any suspicion—is needed to search a cell phone at the border. The defendant, Chinwendu Alisigwe, is a lawful permanent resident suspected of participating in fraud schemes. Returning to the United States from international travel, he was stopped at JFK by border officials who asked him to unlock his phone. He complied, and officials scanning for fraud records reviewed his device and found evidence of alleged fraud.
According to the Second Circuit, this was categorically permissible:
The “longstanding recognition that searches at our borders without probable cause and without a warrant are nonetheless ‘reasonable’ has a history as old as the Fourth Amendment itself.” United States v. Ramsey, 431 U.S. 606, 619 (1977). “The border-search exception 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 country.” Id. at 620. Because “[t]he Government’s interest in preventing the entry of unwanted persons and effects is at its zenith at the international border,” United States v. Flores-Montano, 541 U.S. 149, 152 (2004), “searches made at the border, pursuant to the longstanding right of the sovereign to protect itself by stopping and examining persons and property crossing into this country, are reasonable simply by virtue of the fact that they occur at the border,” Ramsey, 431 U.S. at 616.
Under our precedents, no suspicion is required before the government searches a traveler’s property at the border. See United States v. Irving, 452 F.3d 110, 123 (2d Cir. 2006). Searches of property “are made reasonable by that person’s decision to enter this country.” Id. To be sure, nonroutine searches, which are “more invasive searches, like strip searches, require reasonable suspicion.” Id. But we have held that “the label ‘non-routine’ should generally be reserved for intrusive border searches of the person (such as body-cavity searches or strip searches), not belongings.” United States v. Levy, 803 F.3d 120, 123 n.3 (2d Cir. 2015) (emphasis added). Because a cellphone is property, our precedents establish that the government does not need to have reasonable suspicion before searching a traveler’s cellphone at the border.
We reject Alisigwe’s invitation to extend Riley v. California, 573 U.S. 373 (2014), to conclude that a “search of a cellphone requires a warrant, even in circumstances where a warrantless search is generally allowed.” Appellant’s Br. 32. Riley involved the exception to the warrant requirement for a search incident to an arrest. That exception aims to avoid “the two risks” of “harm to officers and destruction of evidence.” Riley, 573 U.S. at 386. In Riley, the Court explained that because “[t]here are no comparable risks when the search is of digital data,” the rationale for the search-incident-to-arrest exception does not have “much force with respect to digital content on cell phones.” Id. That holding does not implicate the border-search exception, which relies on a different rationale.
Alisigwe asks us to limit the border-search exception to exclude searches “for evidence of crime unrelated to contraband or other border offenses.” Appellant’s Br. 34. But we have previously held that “the validity of a border search does not depend on whether it is prompted by a criminal investigative motive.” Irving, 452 F.3d at 123. Our precedent holding that the government may perform pretextual searches at the border without a warrant means that the government is not limited to searching for contraband or evidence of border offenses. That is because the government’s interest at the border is not limited to detecting physical contraband. Rather, the government has “broad authority to control who and what enters the country.” Tabbaa v. Chertoff, 509 F.3d 89, 102 n.5 (2d Cir. 2007). Searching for evidence of criminality among those entering the country is an exercise of that authority.
According to Judge Menashi, Riley does not apply because the government maintains an interest in detecting digital contraband:
Applying the logic of Riley to the border-search exception leads to the conclusion that the search of a cellphone at the border is a routine search. First, we consider “the government interest.” Riley, 573 U.S. at 386. Unlike the two specific risks that the search-incidentto-arrest exception aims to avoid, the border-search exception furthers the government’s much broader “interest in preventing the entry of unwanted persons and effects.” Flores-Montano, 541 U.S. at 152. That interest is implicated with equal force “when the search is of digital data.” Riley, 573 U.S. at 386. The digital data may itself be the material that the government seeks to exclude from the country. In other words, “cell phones can contain the contraband the border search doctrine means to intercept” such as “digital contraband in the form of child pornography.” United States v. Mendez, 103 F.4th 1303, 1309 (7th Cir. 2024). “The government’s interest in detecting child pornography at the border is just as strong as its interest in intercepting firearms, narcotics, or any other prohibited item.” Id.; see also United States v. Touset, 890 F.3d 1227, 1235 (11th Cir. 2018) (“‘[D]igital’ child pornography poses the same exact ‘risk’ of unlawful entry at the border as its physical counterpart.”).
In this case, Alisigwe sought to bring into the country lists of stolen personally identifiable information. That is contraband whether in digital or physical form. See United States v. Jackson, 618 F. App’x 472, 476-78 (11th Cir. 2015) (describing “a notebook containing names, social security numbers, and birthdates” as “contraband”). The government’s interest in detecting such information does not change based on the format in which it is recorded.
Of particular interest, at least to me, Judge Menashi specifically addressed my argument that the border search power should not extend to digital devices because digital border searches only advance interests in criminal law enforcement, not one of the traditional rationales of the border search exception:
As we have explained, the government may conduct suspicionless border searches “pursuant to the long-standing right of the sovereign to protect itself by stopping and examining persons and property crossing into this country.” Ramsey, 431 U.S. at 616. The examination is not limited to the detection of contraband or other particular items. We have long held that “the validity of a border search does not depend on whether it is prompted by a criminal investigative motive.” Irving, 452 F.3d at 123. In fact, whether the motivation for a customs officer to search a traveler “arises entirely from her own investigation or is prompted by another federal agency is irrelevant to the validity of a border search” because the customs officer is not “prevented by the Fourth Amendment from conducting such a search merely because it furthers another federal agency’s criminal investigation.” Levy, 803 F.3d at 123-24. Even if “the ease of avoiding physical searches underscores that the searches are designed to identify wrongful actors, not to find contraband,” Kerr, supra note 12, at 124-25, that would not undermine the justification for a border search because the border-search exception furthers the governmental interest in preventing wrongful actors from entering the country.
The court did not decide whether a more invasive forensic search might yield a different result, since the case involved only a manual search—where the officer relied on the phone’s operating system and apps to skim through user-accessible files. The court also rejected a First Amendment challenge. Judge Eunice Lee concurred, agreeing that there is no warrant requirement but arguing that some form of suspicion should be required.
I deeply appreciate the engagement with my scholarship on both the majority’s reasoning and the concurrence. For law professors, such judicial engagement with scholarly work is an honor. With that in mind, I think it’s useful to be explicit about where I believe the Second Circuit went astray on this particular issue.
First, as I explain in my chapter, the contraband argument doesn’t fully capture the problem. The issue is that the government’s interest tied to contraband that justifies the physical border search exception is not to simply “detect” contraband, as the Second Circuit suggests, but to prevent its importation. Consider fentanyl. The government aims to stop fentanyl from entering to prevent its use domestically. The theory is that hindering entry reduces domestic availability. Yet here the government was seeking fraud records to prove a crime, not concerned with preventing the records from entering. It was a law-enforcement interest in evidence, not a keep-it-out contraband interest.
Second, regarding the broader notion of permitting criminal-enforcement motivation to justify the border-search power, I believe the Court may have conflated two distinct inquiries that should remain separate: (1) the rationale that grounds a given reasonableness rule and (2) whether, in applying that rule, pretextual use of the doctrine is permissible.
Let’s begin with (1). In the realm of physical objects, the Supreme Court has explained that the border-search power rests on protecting the sovereign’s interests in contraband detection, immigration enforcement, and tariff collection. Criminal law enforcement, by contrast, is not among the recognized interests that justify the border-search exception. It is simply not a stated interest that the doctrine recognizes, because the ordinary response to that interest is the warrant requirement.
Conversely, Fourth Amendment jurisprudence generally cautions against evaluating police action based on the officer’s subjective intent. That is relevant to the second question. There are exceptions where purpose matters, but typically, subjective intent is irrelevant. So, in the physical setting, you have first the border exception grounded in the sovereign’s interests, and then, if applicable, pretextual use for criminal law enforcement at the second stage.
From my reading of the Second Circuit’s decision, the court intertwines these two questions. Because pretextual criminal enforcement is permissible (question 2), criminal enforcement becomes a legitimate governmental interest justifying border searches (question 1). The government can inspect cell phones at the border to collect evidence about “wrongful actors”—that is, criminals—without any showing of probable cause or even suspicion because the border doctrine allows it in service of crime-solving, not the classic sovereignty concerns alone. In effect, the government is permitted to rummage through everyone’s phone for crime-related evidence without cause under the banner of a border-power that is supposed to serve broader sovereign interests.
In my view, however, these two questions should remain distinct. Following the Riley approach, we must assess whether digital searches advance the interests the Court has tied to the border-search exception. Expanding those interests through a pretext-based justification runs counter to the Riley framework by broadening government aims to the point where virtually anything could be sought under the guise of preventing crime. I don’t view that as consistent with Riley.
Will the Supreme Court take up this case, or at least the central issue it raises, in the near future? Before Chatrie, I would have said the odds were slim. The Court would typically require a clear split among the circuits. But Chatrie demonstrated that the justices may be willing to tackle major Fourth Amendment questions in a digitally oriented era even without a circuit split.
If the Court accepted Chatrie for review, it could also consider the border-search exception for cell phones. And it should. This is a particularly consequential issue, and it isn’t an easy one: Alisigwe was argued as far back as March 2025. A multitude of lower courts have weighed in, offering a variety of rationales. Regardless of the eventual answer, the final word should come from the Supreme Court.
As always, stay tuned.
