In the first victory since former contractor Edward Snowden leaked classified security documents to the world, a US federal judge said Monday that the National Security Agency's mass data collection program of American phone records is unconstitutional, and that there is no proof such information "actually stopped an imminent terrorist attack." Judge Richard J. Leon of the District of Columbia ordered the Obama administration to cease its spying on the two men that brought the case forward, as well as destroy all records of their calling history. The plaintiffs were Larry Klayman and Charles Strange, both conservative legal activists. "I cannot imagine a more 'indiscriminate' and 'arbitrary' invasion than this systematic and high-tech collection and retention of personal data on virtually every single citizen for purposes of querying and analyzing it without prior judicial approval," wrote Leon in his 68-page ruling. "Surely, such a program infringes on 'that degree of privacy' that the founders enshrined in the Fourth Amendment." The Fourth Amendment of the US constitution prohibits unreasonable search and seizure, and mandates that all warrants be issued on the basis of probable cause. However "in light of the significant national security interests at stake in this case and the novelty of the constitutional issues," Leon said he would give the government time to appeal the ruling. Responding to the ruling, Snowden released a statement to journalist Glenn Greenwald, who first reported on the leaks. "I acted on my belief that the NSA's mass surveillance programs would not withstand a constitutional challenge, and that the American public deserved a chance to see these issues determined by open courts," he said. "Today, a secret program authorized by a secret court was, when exposed to the light of day, found to violate Americans' rights. It is the first of many.