The Supreme Court on Friday handed down what is arguably the most consequential privacy decision of the digital age, ruling that police need a warrant before they can seize people’s sensitive location information stored by cellphone companies. The case specifically concerns the privacy of cellphone location data, but the ruling has broad implications for government access to all manner of information collected about people and stored by the purveyors of popular technologies. In its decision, the court rejects the government’s expansive argument that people lose their privacy rights merely by using those technologies. Carpenter v. U.S., which was argued by the ACLU, involves Timothy Carpenter, who was convicted in 2013 of a string of burglaries in Detroit. To tie Carpenter to the burglaries, FBI agents obtained — without seeking a warrant — months’ worth of his location information from Carpenter’s cellphone company. They got almost 13,000 data points tracking Carpenter’s whereabouts during that period, revealing where he slept, when he attended church, and much more. Indeed, as Chief Justice John Roberts wrote in Friday’s decision, “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.”.
