Slate: Sotomayor, Fourth Amendment Visionary

Slate: Sotomayor, Fourth Amendment Visionary by Mark Joseph Stern

How the Supreme Court vindicated the justice’s prescient theory of digital privacy.

Can the government access records of your cellphone’s location history over a period of weeks, months, even years, without obtaining a warrant? On Friday, the Supreme Court ruled forcefully that it cannot in Carpenter v. United States, perhaps the most important Fourth Amendment decision of the 21st century so far. Chief Justice John Roberts’ majority opinion—joined only by the court’s liberals in a 5–4 ruling—has been widely praised for putting real constitutional limits on the modern surveillance state. But Roberts’ decision drew heavily from ideas put forth by Justice Sonia Sotomayor in a prescient concurring opinion six years ago. Indeed, Carpenter might not have been possible had Sotomayor not already laid the groundwork for a dramatic expansion of digital privacy.