The Gulf of Tonkin incident (), also known as the USS "Maddox" incident, was an international confrontation that led to the United States engaging more directly in the Vietnam War. It involved both a proven confrontation on August 2, 1964 and a claim of a second confrontation on August 4, 1964 between ships of North Vietnam and the United States in the waters of the Gulf of Tonkin. The original American report blamed North Vietnam for both incidents, but the Pentagon Papers, the memoirs of Robert McNamara, and NSA publications from 2005, suggest that the dismissal of legitimate concerns regarding the veracity of the second incident by Department of State and other government personnel was used to justify an escalation by the US to a state of war against North Vietnam.