June 22, 2018 – The Supreme Court ruled today that law enforcement officers must have a warrant in order to obtain historic cell site location information. In one of the most widely-anticipated decisions in a blockbuster year for the Supreme Court, the Court found 5-4 in Carpenter v. U.S. that collecting 127 days of cell site location information requires a warrant. The Court rejected the government’s argument that the third-party doctrine, which holds that an individual loses Fourth Amendment protections in data voluntarily shared with a third party, nullified the warrant requirement.
“This case has enormous implications for privacy in the digital age,” said Greg Nojeim, Director of CDT’s Freedom, Security & Technology Project. “The Court’s reasoning in this case will be applied to other collections of data, making the Fourth Amendment much more relevant to our digital lives. Prior to this decision concerning metadata, content was the only communications information that required a warrant under the Fourth Amendment when held by a third party.”
The Court’s ruling affirms the premise that “[a] person does not surrender all Fourth Amendment protection by venturing into the public sphere.” The Court noted that many people “compulsively carry their cell phones with them all the time,” and that the affiliated location data reveals a great deal about an individual. “Mapping a cell phone’s location over the course of 127 days provides an all-encompassing record of the holder’s whereabouts. …[T]he time-stamped data provides an intimate window into a person’s life, revealing not only his particular movements, but through them his ‘familial, political, professional, religions, and sexual associations.’”
CDT submitted a brief in the case arguing that the Court should account for new technologies. CDT urged the Court to base its determinations in this area on the sensitivity of the data sought by law enforcement, and whether the person to whom it pertains would reasonably expect that it was going to be made available to others. The Court agreed with this reasoning when it noted that 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.”
The Court’s Carpenter decision follows a series of decisions at the state level to impose warrant requirements for cell phone location information. Currently, courts or legislatures in eight states require state and local law enforcement officials to obtain warrants in order to gain access to cell phone location information.
“Now that the Court has ruled that a warrant is required for law enforcement access to long-term location tracking information, it will be up to Congress to answer the questions the Court left open,” Nojeim said. “It’s crucial for lawmakers to apply a warrant requirement for shorter periods or when the government wants to locate a person at one particular moment,” he added. “Congress must finish the work started by the Court and safeguard our phones from becoming government tracking devices.” Congress engaged in a similar gap-filling exercise after the Court ruled in 1967 in Berger v. New York that a state wiretapping law lacked adequate protections to survive Fourth Amendment scrutiny.
“Congress should also close the data-laundering loophole that has opened up to permit lawless location tracking,” Nojeim added. “Telecommunications companies are selling sensitive location information to third parties who sell the information to law enforcement, thereby evading the court order requirement that would apply if law enforcement had sought the location information directly from the carrier.”