In a 5-4 vote, the Supreme Court of the United States (SCOTUS ) ruled today that law enforcement must obtain a search warrant before obtaining and accessing cell phone location information from mobile carriers and other entities.
SCOTUS justices ruled that a phone's location data, even if stored on a third-party service, deserves the same level of privacy protections under the Fourth Amendment as data stored on the device itself.
Police have always needed a warrant to access data stored on a device, hence the Supreme Court ruled that one is also needed to access location data stored by mobile carriers and similar companies.
"While individuals regularly leave their vehicles, they compulsively carry cell phones with them all the time," wrote SCOTUS Chief Justice John Roberts in the court's decision.
"Accordingly, when the Government tracks the location of a cell phone it achieves near perfect surveillance-------, as if it had attached an ankle monitor to the phone's user. Moreover, the retrospective quality of the data here gives police access to a category of information otherwise unknowable.
"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," Chief Justice Roberts said.
As such, SCOTUS justices ruled that there's a need to limit the tracking of all cell phone location, and restrict access to such data only if law enforcement can obtain a warrant from a US judge after producing evidence of probable cause.
Chief Justice Roberts clarified that a warrant can be waived in extreme scenarios, such as when authorities are dealing with emergencies of life and death, or when handling national security matters.
The ruling came in the Carpenter v. US case filed in 2011. Back then, the FBI arrested members of a gang who committed armed robberies at several RadioShack and T-Mobile stores.
While under questioning, gang members revealed they worked under the leadership of Timothy Carpenter. Police obtained a court order for Carpenter's cell phone location information, which put him near the robberies.
Carpenter received more than 100 years in prison, but he would have walked free if police did not have his cell phone's location data.
Carpenter fought his case by arguing that a court order should not have been enough to obtain access to his mobile's location data, and a search warrant should have been obtained instead, which needed the FBI to present more extensive evidence in front of a judge that he had committed a crime.
Today's Supreme Court ruling is one of great importance, but not solely for privacy rights advocates. The Supreme Court's decision also breaks a well-established train of thought that argues the user loses his right to privacy when he allows his data to be stored with a third-party.
Several US government officials and many privacy advocacy groups have praised the SCOTUS decision.