The publication of a slew of documents relating to the war in Afghanistan represents one of the largest ever leaks, but what role has illicit information played in US politics?
Perhaps the most famous political scandal in US history also represents the most notorious leak.
The supply of information that "Deep Throat" - later revealed to be FBI deputy director Mark Felt - provided led reporters Bob Woodward and Carl Bernstein to uncover the Watergate scandal.
Without the illicit information it is hard to imagine the full extent of the cover-up over the burglary of the Democratic National Committee offices would have come to light, or that President Richard Nixon would have been forced to resign.
The Pentagon Papers was another leak that had a major impact.
A study of the US military's role in Vietnam (formerly Indochina) from 1945 to 1967, they were supplied to a New York Times journalist in 1971.
The publication, which the Nixon administration tried to stop, revealed details about the way the war had been escalated which seemed to contradict what the public had been told by the previous administration of President Lyndon Johnson.
Indeed, many leaks originate in the world of the military or intelligence, where whistleblowers justify the release of sensitive documents by arguing that their classified status would mean wrongdoing might not be revealed.
BBC News | 26 July 2010 - read full report :