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On Friday, the Supreme Court ruled in a five-to-four decision that law enforcement generally must obtain a warrant to gather cellphone location data from network providers. In an age where virtually everyone is carrying a location-tracking device, the decision is a huge win for privacy advocates.


The case of Carpenter v. United States was expected to set new standards for the application of the Third Party Doctrine, a precedent set in the ‘70s and ‘80s that maintains a suspect gives up their expectation of privacy if they share information with a third party. When it comes to the location data an individual shares with a telecom, the ACLU argued that police should have to go through the usual standards of demonstrating probable cause when getting a warrant to collect location data. Nathaniel Wessler, a staff attorney for the ACLU, told Gizmodo last November, “The court four decades ago could not possibly have imagined the world we live in today, where it’s really impossible to go through our daily lives without records of our most private activities being saved on the servers of companies we have relationships with.”

Chief Justice John G. Roberts Jr. wrote the majority opinion in which he insisted today’s decision is narrow. “We hold only that a warrant is required in the rare case where the suspect has a legitimate privacy interest in records held by a third party,” he wrote. Roberts specifically said the ruling does not weigh-in on the legality of real-time cell site location information (CSLI) or “a download of information on all the devices that connected to a particular cell site during a particular.”




All the court is saying today is that in the case of obtaining location records from a cellphone company, police will need to demonstrate probable cause. Previously, the Stored Communications Act set the precedent that law enforcement need only go to court and demonstrate “specific and articulable facts showing that there are reasonable grounds to believe” what could be found in the records might be relevant and material to a criminal investigation. Probable cause carries more strict and codified standards in its application. The court did give the exception that a warrant does not necessarily have to be obtained in cases in which there could be an immediate threat or danger to life.

The case began with a man named Timothy Ivory Carpenter who was sentenced to 116 years in prison for his role in a string of robberies at various RadioShack stores in Michigan and Ohio. Police had witnesses and surveillance footage placing Carpenter at the locations at which the robberies took place, but they also used 186 pages of documents obtained from cell carrier that outlined his call history and location data. The records comprised data over the course of 127 days and included unrelated information about Carpenter’s movements including where he slept at night and how often he attended church.

Chief Justice Roberts wrote, “because location information is continually logged for all of the 400 million devices in the United States—not just those belonging to persons who might happen to come under investigation— this newfound tracking capacity runs against everyone.” The Justice worried that “police need not even know in advance whether they want to follow a particular individual, or when,” and argued this violated the Fourth Amendment’s privacy protections. “Only the few without cell phones could escape this tireless and absolute surveillance,” the Justice said.

There’s still reason to believe that further debate on the issue will be hashed out in the courts. Roberts’ pronouncement that the court holds only that “a warrant is required in the rare case where the suspect has a legitimate privacy interest in records held by a third party,” is vague enough that it could be contentious.


The ACLU appears to be more than pleased with the ruling. In a press release it quoted Harold Gurewitz, an attorney who worked alongside the civil liberties organization on the Carpenter case, as saying, “The court’s decision is a vindication of the arguments we have persistently made on behalf of Timothy Carpenter throughout this litigation — that the Constitution’s privacy protections fully apply to the digital location data created by using cell phones.”

[Supreme Court of the United States]