Why Border Searches of Phones and Laptops Should Require a Warrant: Key Questions Answered

Electronic devices like smartphones and laptops contain vast amounts of personal data—from private messages and photos to financial records and medical information. Yet at U.S. borders, customs officers can search these devices without a warrant, raising serious Fourth Amendment concerns. A recent case, U.S. v. Belmonte Cardozo, has brought this issue before the Fourth Circuit Court of Appeals, with the Electronic Frontier Foundation (EFF) and other civil liberties groups arguing that a warrant based on probable cause is essential. Below, we explore key aspects of this legal battle.

What is the case U.S. v. Belmonte Cardozo about?

This case involves a U.S. citizen who was returning from Bolivia and had his cell phone manually searched at Dulles Airport near Washington, D.C. The traveler had already been flagged for secondary inspection. During the search, border officers discovered child sexual abuse material (CSAM) on his phone. He was later charged and convicted of child pornography and sexual exploitation of minors for using social media to solicit explicit images. The evidence obtained from the warrantless search was crucial to the prosecution. The defendant moved to suppress that evidence, arguing the search violated the Fourth Amendment, but the district court denied the motion. Now, the Fourth Circuit is hearing an appeal, and groups like the EFF, ACLU, and NACDL have filed amicus briefs urging the court to require warrants for border device searches.

What arguments did EFF and other groups make in their amicus brief?

In their amicus brief, EFF, the national ACLU, multiple ACLU affiliates, and the National Association of Criminal Defense Lawyers (NACDL) argued that the Fourth Circuit should apply the same legal standard to both manual and forensic searches of electronic devices at the border: a warrant supported by probable cause and issued by a neutral judge. They emphasized that the highly personal nature of data on phones and laptops—including political views, religious practices, health information, and intimate relationships—requires consistent judicial oversight. The brief also pointed out that allowing different standards for basic vs. advanced searches would create a loophole that undermines privacy. Additionally, the Knight Institute and Reporters Committee for Freedom of the Press filed a separate brief focusing on First Amendment concerns, such as the chilling effect on journalists and activists.

What is the difference between manual and forensic device searches at the border?

Manual searches, also called "basic" searches, involve a border officer physically tapping or clicking through the device, opening apps, and looking at files. Forensic searches, or "advanced" searches, require connecting another device to the traveler’s phone or laptop to extract and analyze data using specialized software. This process can create a detailed report of the owner’s activities, communications, and stored information. Both types are highly privacy-invasive because they can reveal the most intimate aspects of a person’s life. In Fiscal Year 2025, U.S. Customs and Border Protection conducted over 55,000 such searches. EFF argues that the legal standard should be the same for both methods—a warrant based on probable cause—because a device’s contents are equally private regardless of the search technique.

Why is a warrant needed for border device searches under the Fourth Amendment?

The Fourth Amendment protects against unreasonable searches and seizures, but border searches have historically been treated as an exception. However, the Supreme Court has recognized that electronic devices are fundamentally different from physical luggage because they store vast amounts of personal data. In Riley v. California, the Court held that police generally need a warrant to search a cell phone incident to arrest. EFF argues that the same logic applies at the border: a traveler’s device may contain information far beyond what any suitcase could hold—from private conversations to medical records. A warrant requirement ensures that a neutral judge reviews the government’s evidence before allowing a search, preventing fishing expeditions. Without a warrant, border searches can become an end-run around Fourth Amendment protections, especially given the soaring number of device searches each year.

Are manual searches of electronic devices at the border less invasive than forensic searches?

While manual searches might seem less intrusive because they don’t involve connecting external hardware, they can still expose highly sensitive information. An officer swiping through a phone can view messages, photos, contacts, and app data—everything that makes a device a digital record of a person’s life. Forensic searches simply automate that process and produce a searchable report. Both methods allow access to content revealing political affiliations, sexual orientation, religious beliefs, and more. EFF’s brief argues that applying different legal standards—say, requiring a warrant only for forensic searches—would create an arbitrary distinction. The core privacy interest remains the same: preventing the government from rummaging through personal data without individualized suspicion. Therefore, a warrant validated by probable cause should be required regardless of how the search is conducted.

What do the statistics on border device searches tell us about privacy risks?

In Fiscal Year 2025, U.S. Customs and Border Protection reported 55,318 device searches—both manual and forensic—a number that has been rising steadily. These searches occur without any warrant or individualized suspicion, often targeting travelers based on vague flags or profiling. Each search can reveal not only the traveler’s own data but also that of family, friends, and colleagues. The sheer volume means that vast amounts of private information are being accessed by border officers. Civil liberties groups argue that such unchecked searches create a chilling effect on freedom of speech and association, especially for immigrants, journalists, and activists. The lack of meaningful oversight allows the government to collect data from innocent people, turning border checkpoints into data-dragnet zones. Requiring a warrant would curb these abuses by ensuring searches are targeted and justified.

What role do amicus briefs play in this case?

Amicus briefs—or "friend of the court" filings—allow third parties to provide additional legal perspectives to the appeals court. In U.S. v. Belmonte Cardozo, the EFF-led brief highlights Fourth Amendment principles, while another brief from the Knight Institute and Reporters Committee focuses on First Amendment implications. These briefs help the judges understand broader societal impacts beyond the specific facts of the case. The court may cite such arguments in its ruling. By emphasizing that warrantless border device searches threaten privacy and free expression, the briefs aim to persuade the Fourth Circuit to set a new precedent requiring a warrant. A positive decision could significantly protect the rights of all travelers entering the United States.