North Vietnamese torpedo boats reportedly made two sets of attacks on American vessels in the Gulf of Tonkin, off Vietnam (August 2 and 4). It was the basis of the Tonkin Gulf Resolution, committing major American forces to the Vietnam War, though some critics later questioned the facts. By year's end, 20,000 to 25,000 American troops and hundreds of American warplanes were in Vietnam.
Tonkin Gulf Resolution (August 7): American congressional resolution, passed in the House unanimously and in the Senate with only two dissenting votes, authorized President Lyndon B. Johnson to take the United States into the undeclared Vietnam War, which he immediately did. The authorization was granted after reported North Vietnamese torpedo boat attacks on two American naval vessels in the Gulf of Tonkin; the reports were later the subject of great controversy.