The Gulf of Tonkin Incident began with an “imaginary” attack by three North Vietnamese torpedo boats on the Maddox, a U.S. destroyer, in the Gulf of Tonkin on 2 August 1964. Two days later, that vessel and another U.S. destroyer in the area both reported themselves under renewed attack, although North Vietnam subsequently insisted that it hadn’t attacked — and no attack is now believed to have occurred on the 4th of August.

Within hours, Johnson ordered retaliatory air strikes on the bases of the North Vietnamese boats and announced, in a television address to the American public the same evening, that U.S. naval forces had been attacked. In a message he sent to Congress the following day, the President affirmed that “the North Vietnamese regime had conducted further deliberate attacks against U.S. naval vessels operating in international waters.”
Johnson requested approval of a resolution “expressing the unity and determination of the United States in supporting freedom and in protecting peace in southeast Asia”. He said that the resolution should express support “for all necessary action to protect our Armed Forces” — but repeated previous assurances that “the United States… seeks no wider war”. As the nation entered the final three months of political campaigning for the 1964 elections (in which Johnson was standing for election), the president contended that the resolution would help “hostile nations… understand” that the United States was unified in its determination “to continue to protect its national interests.”[2]