Pinback button issued in support of 27 U.S. servicemen charged with mutiny, c. 1969.The Presidio Mutiny was a sit-down protest carried out by 27 prisoners at the Presidio stockade in San Francisco, California on October 14, 1968. The stiff sentences given out at courts martial for the participants (known as the Presidio 27) attracted attention to the extent of sentiment against the Vietnam War in the armed forces.