PRISM is a clandestine national security electronic surveillance program operated by the United States National Security Agency (NSA) since 2007. PRISM is a government code name for a data-collection effort known officially by the SIGAD US-984XN.
On September 11, 2007, U.S. President George W. Bush signed the Protect America Act of 2007, allowing the NSA to start a massive domestic surveillance program. The program is operated under the supervision of the U.S. Foreign Intelligence Surveillance Court (FISC) pursuant to the Foreign Intelligence Surveillance Act (FISA).
Its existence was leaked five years later by NSA contractor Edward Snowden, who claimed the extent of mass data collection was far greater than the public knew, and included “dangerous” and “criminal” activities in law. The disclosures were published by The Guardian and The Washington Post on June 6, 2013.
A document included in the leak indicated that PRISM was “the number one source of raw intelligence used for NSA analytic reports.”
The leaked information came to light one day after the revelation that the FISC had been ordering a business unit of the telecommunications company Verizon Communications to turn over to the NSA logs tracking all of its customers’ telephone calls on an ongoing daily basis.
U.S. government officials have disputed some aspects of the Guardian and Washington Post stories and have defended the program by asserting it cannot be used on domestic targets without a warrant, that it has helped to prevent acts of terrorism, and that it receives independent oversight from the federal government’s executive, judicial and legislative branches.
NSA Director General Keith B. Alexander has stated[when?] that communications surveillance helped prevent more than 50 potential terrorist attacks worldwide (at least 10 of them in the U.S.) between 2001 and 2013, and PRISM contributed in over 90 percent of those cases.
On June 19, 2013, U.S. President Barack Obama, during a visit to Germany, stated that the NSA’s data gathering practices constitute “a circumscribed, narrow system directed at us being able to protect our people.”