On August 7, 1964, in response to an alleged North Vietnamese attack on the USS Maddox three days earlier, the US Congress passed the Gulf of Tonkin Resolution, approving and supporting "the determination of the President, as Commander in Chief, to take all necessary measures to repel any armed attack against the forces of the United States and to prevent further aggression." The resolution marked a major escalation in the US role in the Vietnam War. Review the text of the resolution and President Lyndon Johnson's message to Congress.