On Friday, June 22, the Supreme Court ruled on Carpenter v. United States deciding that the government cannot access records of your cell phone’s location without a warrant. This important Fourth Amendment decision came to a 5-4 ruling, with the liberal justices voting in favor of Carpenter. This decision, while credited to Chief Justice John Roberts, drew heavily from the 2012 work of Justice Sonia Sotomayor, the first Hispanic supreme court justice.
United States v. Jones was a 2012 case with similarities to the Carpenter case. In the Jones case, a police officer attached a GPS tracking device to the bottom of Antoine Jones’ car without a valid warrant, then tracked its movement for nearly a month. The information was used to charge Jones with drug trafficking, but he argued that the police officer had violated his Fourth Amendment right against search and seizure. The Supreme Court agreed with Jones, and while the majority opinion written by Justice Antonin Scalia was signed by Sotomayor, she wrote a concurring opinion which came to serve as inspiration for Friday’s Carpenter decision.
In Sotomayor’s concurrence, she stated that “physical intrusion is now unnecessary to many forms of surveillance.” She noted that it is increasingly common for the government to “assemble data that reveal private aspects of identity… [without] physical invasion on property.”
Since 2012, Sotomayor’s opinion has been cited several times in lower courts. In 2014 it was even cited by Roberts in a landmark opinion holding that the police may not search cellphones without a warrant. In the Carpenter case, the American Civil Liberties Union, who represented Carpenter, also referenced Sotomayor’s concurrence from the Jones case.
While Roberts chose to exercise his right as chief justice to assign the opinion to himself, much of the opinion drew from Sotomayor’s. Moving forward, this decision is expected to settle many 21st-century privacy cases which tend to be vague and complicated due to technology.