“In 1979 the court upheld Smith’s conviction, and his 10-year prison term. Almost 35 years later, the court’s decision — in a case involving the recording of a single individual’s phone records — turns out to be the basis for a legal rationale justifying governmental spying on virtually all Americans. Smith v. Maryland, as the case is titled, set the binding precedent for what we now call metadata surveillance. That, in turn, has recently been revealed to be the keystone of the National Security Agency’s bulk collection of U.S. telephone data, in which the government chronicles every phone call originating or terminating in the United States, all in the name of the war on terror.”
http://www.wired.com/threatlevel/2013/10/nsa-smith-purse-snatching/