When, at the height of the Vietnam War in the 1970s, a disaffected Pentagon analyst published explosive details about how the White House was running the campaign, US military commanders soon found themselves being forced into ordering a humiliating retreat from the war zone.
The Pentagon Papers, which were leaked to the New York Times in 1971 by Daniel Ellsberg, a Democrat-supporting defence expert, lifted the lid on how successive presidents going back to Harry Truman had deliberately misled the American public on the conduct of the war.
