The U.S. Congress approves the Gulf of Tonkin Resolution, granting President Lyndon B. Johnson authority "to take all necessary measures to repel any armed attack against the forces of the United States and to prevent further aggression."
The resolution followed the Gulf of Tonkin incident where the USS Maddox engaged North Vietnamese torpedo boats. Two days later a second attacked was reported but it is now believed not to be factual. The Resolution lead to increased U.S. involvement in the Vietnam War. More