“If you win this case,” Supreme Court Justice Stephen Breyer told the Obama administration’s lawyer during oral argument in U.S. v. Jones last fall, “there is nothing to prevent the police or the government from monitoring 24 hours a day the public movement of every citizen of the United States.” That prospect, Breyer said, “sounds like 1984.”

Fortunately, the government did not win the case, writes Senior Editor Jacob Sullum. But the Court’s unanimous decision, announced in January, may not delay Breyer’s 1984 scenario for long. Unless the Court moves more boldly to restrain government use of new surveillance technologies, the Framers’ notion of a private sphere protected from “unreasonable searches and seizures” will become increasingly quaint.