The USS Maddox destroyed several torpedo boats belonging to North Vietnam in Aug. 02 1964. It was claimed that the boats were stalking the USS Maddox, which was patrolling the North Vietnam’s coast on an intelligence mission.
Another attack by USS Turner Joy and Maddox, which were in the same area, was done two days later. However, the reasons behind the attacks were sketchy (The Vietnam War the Bitter End 1969 – 1975, 1997).
After these attacks, the Tonkin Gulf resolution was passed on Aug 04, 1964 during the presidency of Lyndon B. Johnson authorizing military action in south East Asia. This was because North Vietnamese torpedo boats, which were situated in the Gulf of Tonkin, attacked US destroyers without any kind of provocation. On Aug. 7, the same year the US senate approved air strikes towards North Vietnam army.