In United States v. Smith, a district court judge in New York set a precedent by ruling that a warrant is required for cell phone searches at the border, except in exigent circumstances. For a century, the Supreme Court has recognized a border search exception to the Fourth Amendment’s warrant requirement, allowing warrantless and often suspicionless searches of items crossing the border, including luggage. However, the application of this exception to smartphones and other electronic devices that store vast amounts of personal information has not been addressed by the Supreme Court.

Some federal appellate courts have narrowed the border search exception’s application to digital data. The Ninth Circuit held in United States v. Cano that a warrant is necessary for device searches at the border seeking data other than digital contraband. The Fourth Circuit similarly ruled in United States v. Aigbekaen that a warrant is required for forensic device searches at the border related to domestic criminal investigations. These decisions, along with the Smith court’s ruling, were influenced by the Supreme Court’s decision in Riley v. California, which held that a warrant is needed to search an arrestee’s cell phone.

The Smith court applied the balancing test from Riley to the border context, considering the government’s interests in warrantless access to cell phone data against travelers’ privacy interests. The court concluded that the government’s interests in searching digital data at the border are weaker than its interests in searching physical items. Modern cell phones contain extensive personal information, and travelers should not be expected to relinquish their privacy rights by simply carrying a cell phone. Additionally, the court noted that the internet and cloud storage make it possible for data on a cell phone to enter the country even if the physical device is stopped at the border.