It sometimes seems technology provides a moving target for the Fourth Amendment, evolving new means of snooping on people while courts struggle to keep up. That's the case with Chatrie v. United States, in which the U.S. Supreme Court will soon determine how much leeway the authorities have to electronically search whole geographic areas to discover who was present. Civil liberties groups like the Institute for Justice and the Electronic Frontier Foundation are scrambling to hold the line on search-and-seizure protections in a world where smartphones create a constant record of most people's locations.
