Jacob Sullum on Warrantless Cellphone Tracking

Last month the New Jersey Supreme Court ruled that police generally need a warrant to obtain information about the locations of cellphone users. Last week the U.S. Court of Appeals for the 5th Circuit said just the opposite. The first decision was based on Article I, Paragraph 7 of the New Jersey Constitution, while the second was based on the Fourth Amendment to the U.S. Constitution. But as Senior Editor Jacob Sullum notes, those provisions are virtually identical, banning "unreasonable searches and seizures" of "persons, houses, papers, and effects." The crucial difference between the two decisions, Sullum says, is the "third party doctrine," an increasingly alarming menace to privacy.