For the last decade or so, lower courts have been grappling with how the Fourth Amendment applies to searches of digital devices such as cell phones at the international border. Physical property can be searched when it crosses the border to advance sovereign interests in preventing the important of contraband, enforcing immigration laws, and making sure tariffs are paid. But do these rationales still apply to allow the search of a cell phone? When you travel internationally, should the U.S. government be allowed to search your cell phone without limit? Or should a warrant be required, or at least sufficient legal suspicion?
My own view is that these government interests aren't advanced by digital searches, and that a warrant should be needed to search a cell phone at the border, at least in the context of devices held by U.S. citizens. As I explained my book, The Digital Fourth Amendment, I see this as just like Riley v. California, the case holding that the search-incident-to-arrest exception does not apply to cell phones. As in Riley, the physical world government interests that justify the rule for physical property just don't carry over to the digital setting. Extending the rule to cell phones has to "rest on its own bottom," Riley tells us, and I don't think it can.
Think about it. You can't hide a person in a phone, and the data inside a cell phone isn't subject to tariffs. And while there is an interest in preventing contraband from being brought into the country in the form of digital CSAM (child sexual abuse materials), border searches of digital devices aren't actually conducted for that reason. The government searches phones when people cross the border for ordinary criminal enforcement reasons. It's trying to catch bad people, not prevent the importation of contraband. The government is searching at the border only because carrying cell phones paired with traditional border search powers gives them a windfall that helps them catch criminals. I don't think the Fourth Amendment allows them that windfall, given that these searches are categorically undertaken for ordinary criminal law enforcement, not the special sovereignty concerns justifying the border search exception. So I think a warrant is needed, at least for searches of citizens' devices. If you want the details of my argument, you can read the chapter of the book on this posted at SSRN.
