The Supreme Court on Monday agreed to review a case examining whether the Constitution requires law enforcement to get a warrant before obtaining cellphone location data for particular users.
The case, Carpenter v. United States, is the most significant legal dispute at the intersection between technology and the Fourth Amendment since the high court unanimously ruled in 2014 that the law forbids authorities from conducting warrantless searches of the contents of smartphones and similar devices. The Fourth Amendment protects people against unreasonable searches and seizures.
The extent to which prosecutors and other law enforcement officials can request cell-phone location data has long vexed lower courts — in part because the data is “third-party” information that’s in possession of telecommunication companies, not the targeted users themselves.
Relying on a 1979 case known as Smith v. Maryland, courts across the country have ruled that law enforcement officials don’t need a court-approved warrant to access this information. The courts reason that individuals lose a “legitimate expectation of privacy” when they voluntarily hand information about the numbers they dial to telecoms.
For example, in the case of Timothy Carpenter ― the petitioner at the center of this Supreme Court case ― federal prosecutors investigating a series of robberies sought and obtained 127 days’ worth of cell-site information about him and his movements.
With this information, “the government could identify the area in which Carpenter’s phone was located and could thereby deduce Carpenter’s location and movements at multiple points each day,” said lawyers for the American Civil Liberties Union in a petition urging the Supreme Court to hear the case.
According to the ACLU, Carpenter’s call record painted “a very detailed accounting of everywhere he went.”
“The time has come for the Supreme Court to make clear that the longstanding protections of the Fourth Amendment apply with undiminished force to these kinds of sensitive digital records,” Nathan Freed Wessler, an attorney with the ACLU’s Speech, Privacy, and Technology Project, said in a statement.
The federal government has resisted efforts to get the Fourth Amendment to apply to these location records. Instead, government lawyers point to a broad provision of federal law that gives them grounds to obtain them if they can show the records “are relevant and material to an ongoing criminal investigation.”
Based on that provision, law enforcement officials obtain tens of thousands of such records from the likes of AT&T and Verizon every year.
In a 2012 ruling on the constitutional limitations of GPS surveillance, Justice Sonia Sotomayor warned about the potential pitfalls of not curbing the authority of law enforcement to get access to a person’s every move based on “information voluntarily disclosed to third parties.”
“This approach is ill suited to the digital age,” Sotomayor wrote, “in which people reveal a great deal of information about themselves to third parties in the course of carrying out mundane tasks.”
Now that the Supreme Court has added the case to its next term, which begins in October, Sotomayor and her colleagues are poised to offer clarity in this contested area of law.
This article has been updated with more background and arguments on the case.