Supreme Court Rules Police Need Warrant to Track Cell Phones

Friday’s 5-4 decision reverses a previous ruling that cell phone location data is not protected by the Fourth Amendment and therefore doesn’t require a warrant.

Supreme Court Rules Police Need Warrant to Track Cell Phones

The ruling does include exceptions for emergencies such as bomb threats and child abductions.

The U.S. Supreme Court ruled Friday that police must obtain a search warrant to access cell phone location data to use as trial evidence.

“We decline to grant the state unrestricted access to a wireless carrier’s database of physical location information,” Chief Justice John G. Roberts Jr. wrote for the majority.

The 5-4 decision reverses a previous ruling by a Sixth Circuit Court of Appeals judge that police can obtain location data without a warrant if an individual voluntarily shares their information with a third party, such as a cell phone provider, reports NPR.

In Carpenter v. the United States, police gathered months of phone location data from Timothy Carpenter, the suspect in a 2011 robbery trial in Detroit. They gathered 127 days’ worth of data, which consisted of approximately 12,898 different locations, without obtaining a warrant.

The judge ruled that cell phone location data isn’t protected by the Fourth Amendment, which forbids unreasonable search and seizure, and therefore didn’t require a warrant. Carpenter was sentenced to 116 years in prison for his role in the string of robberies.

Justice Roberts ruled the government’s searches of Carpenter’s phone records were considered a Fourth Amendment search.

“The government’s position fails to contend with the seismic shifts in digital technology that made possible the tracking of not only Carpenter’s location but also everyone else’s, not for a short period but for years and years,” he wrote.

The decision did make several exceptions for emergencies like bomb threats and child abductions, according to the NY Times. Police can also still respond to an emergency and obtain records without a warrant.

“Such exigencies include the need to pursue a fleeing suspect, protect individuals who are threatened with imminent harm or prevent the imminent destruction of evidence,” Roberts wrote.

ACLU attorney Nathan Freed Wessler, who represented Carpenter, called Friday’s decision a “groundbreaking victory for Americans’ privacy rights in the digital age.”

“The Supreme Court has given privacy law an update that it has badly needed for many years, finally bringing it in line with the realities of modern life,” he added. “The government can no longer claim that the mere act of using technology eliminates the Fourth Amendment’s protections.”

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About the Author


Amy is Campus Safety’s Executive Editor. Prior to joining the editorial team in 2017, she worked in both events and digital marketing.

Amy has many close relatives and friends who are teachers, motivating her to learn and share as much as she can about campus security. She has a minor in education and has worked with children in several capacities, further deepening her passion for keeping students safe.

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