San Francisco - A federal district court is poised to determine whether the government can use cell phone data obtained without a warrant to establish an individual's location. In an amicus brief filed Monday, the Electronic Frontier Foundation (EFF) and the Center for Democracy & Technology (CDT) argue that this form of surveillance is just as unconstitutional as the warrantless GPS tracking the U.S. Supreme Court already shot down in this case.

"Location data is extraordinarily sensitive. It can reveal where you worship, where your family and friends live, what sort of doctors you visit, and what meetings and activities you attend," said EFF Senior Staff Attorney Marcia Hofmann. "Whether this information is collected by a GPS device or a mobile phone company, the government should only be able to get it with a warrant based on probable cause that's approved by a judge."

In U.S. v. Jones, FBI agents planted a GPS device on a car and then tracked its position every ten seconds for 28 days without a valid search warrant. In a landmark decision earlier this year, the Supreme Court ruled that this violated the Fourth Amendment. The case is now back in the trial court, where Jones is moving to suppress six months of cell phone location data that government investigators obtained – yet again – without a warrant. In Monday's brief, EFF and CDT argue that the Fourth Amendment doesn't allow government investigators to collect cell phone data to track users' locations over a prolonged period of time without a warrant. This right isn't defeated even if cell phone users disclose their locations to service providers when their phones connect to a cell phone tower.

"As Justice Sonia Sotomayor said in the Jones GPS Supreme Court decision, the idea that privacy rights are forfeited simply by giving them to a third party is 'ill-suited to the digital age,'" said EFF Staff Attorney Hanni Fakhoury. "If the government gets its way here, it could jeopardize any expectation of privacy we have in our private movements."

For the full amicus brief in U.S. v. Jones:


Hanni Fakhoury
   Staff Attorney
   Electronic Frontier Foundation

Marcia Hofmann
   Senior Staff Attorney
   Electronic Frontier Foundation