Whether you were born in the U.S., naturalized, or derived or acquired citizenship from U.S. citizen parents, your status as a U.S. citizen gives you important benefits when traveling. Your U.S. passport is a powerful document, giving you protection by the U.S. government when traveling and the right to be readmitted upon your return. You are likely accustomed to receiving the full scope of protections guaranteed by the U.S. Constitution when dealing with authorities at the U.S. borders and other ports of entry.
But how much privacy can you expect when coming back to the the U.S. after international travel? This is a question that is being asked by many lately, as media reports surface about Customs and Border Protection (CBP) officials insisting that U.S. citizens not only undergo the normal questioning and possibly luggage search, but hand over their smartphones, iPads, tablets, laptops, and other electronic devices, along with the passwords thereto, for search and possibly longer-term seizure.
This is a level of scrutiny that goes to one's very sense of privacy. Your whole personal life—what political party you support, who you're dating, what you buy online, and where you've been lately—is probably shown in the texts, emails, photos, and other sources of information that live on your digital devices.
Thus the question many U.S. citizens are asking is, don't I have some level of privacy protection when I'm merely coming back from a trip to, say, London or Hong Kong?
Interestingly, there is no right to privacy explicitly set forth in the U.S. Constitution or federal law. Privacy is a relatively modern concept. The Supreme Court has, however, inferred the existence of a Constitutional right to privacy. Upon this basis, it has struck down laws that, for example, criminalized sodomy, contraceptive use, and abortion.
The more relevant Constitutional right when a U.S. citizen reenters the United States after international travel is the Fourth Amendment. This limits the power of federal and state law enforcement authorities to make arrests, search people and their property, and seize objects and contraband. They must, in situations where the person has a legitimate expectation of privacy, have a reasonable basis to conduct a search or must obtain a warrant after showing probable cause to conduct a search.
But even the Fourth Amendment won't completely cover you or any U.S. citizen when returning from a trip abroad. That's because entry to the United States is viewed as a unique set of circumstances, given its importance for national safety and security. The U.S. Supreme Court discussed this in a case called United States v. Ramsey, 431 U.S. 606 (1977), which basically said that all searches taking place at a U.S. border are reasonable and that the law doesn't give you any expectation of privacy there.
This is an emerging area of U.S. law, and may lead to litigation in the future. For now, however, refusing to give CBP officials access to your phone or other electronic device doesn't seem to work—you are likely to have an unpleasant encounter at a minimum, and possibly have your devices seized with an order for you to return at a later date.
One can hope that other courts will, upon encountering the cases that will inevitable arise concerning this issue, choose to follow the Ninth Circuit, which held in a case called United States v. Cotterman that border agents need to at least have a reasonable suspicion of criminal activity before they search a laptop.
The court's reasoning pointed to the fact that a laptop's contents are highly personal and that such devices "are simultaneously offices and personal diaries. They contain the most intimate details of our lives: financial records, confidential business documents, medical records and private emails. This type of material implicates the Fourth Amendment’s specific guarantee of the people’s right to be secure in their 'papers.'"
If you're entering the U.S. in one of the states that's within the jurisdiction of the Ninth Circuit, you could try asserting the Cotterman holding—but you might end up having to take your case to court to enforce it regardless. And if you're outside the Ninth Circuit, you'll need to decide whether to go along with the CBP request or to hold firm and perhaps end up being the next test case.