The Gulf of Tonkin incident was a minor clash between two US Navy vessels and North Vietnamese torpedo boats in the Gulf of Tonkin off the coast of Vietnam. The clash led to President Lyndon B. Johnson passing the Gulf of Tonkin Resolution through the US Congress and pursuing escalation of the Vietnam War, deploying the first combat troops to fight against the communists.
The small North Vietnamese navy was on high alert due to the South Vietnamese naval bombardments of its ports of Thanh Hoa and Vinh, and, when the US Navy destroyer USS Maddox entered North Vietnamese territorial waters while performing a signals patrol, three North Vietnamese torpedo boats were sent out to confront the vessel. Maddox fired three warning shots, and the torpedo boats responded with torpedoes and machine gun fire. Maddox fired 280 shells at the North Vietnamese boats, and the three ships each sustained damage, while 4 sailors were killed and 6 wounded. No US personnel were harmed, and Maddox was entirely unscathed except for a single bullet hole. The two forces broke off from the clash, and President Lyndon B. Johnson warned the US Congress that he would pursue retaliation against North Vietnam if it continued to act against the US with hostility.
Two days later, US command misinterpreted a North Vietnamese radio message, believing that a call for readiness against another South Vietnamese naval raid was actually a call to resume the attack on the Maddox. While no attack was to come, the US captain informed President Johnson that they were unsure if they were being attacked, but that it was likely. Johnson responded by invoking the War Powers Act and passing the Gulf of Tonkin Resolution, which enabled him to escalate the war on Vietnam and to carry out reprisals against the North Vietnamese. Johnson assured the public that he was not seeking a broader war in Vietnam, but, at 10:40 AM on 5 August 1964, US aircraft bombed four torpedo boat bases and an oil storage facility in Vinh in Operation Pierce Arrow. The North Vietnamese government, unlike the US government, believed the US to be actively seeking a broader war and began to send NVA regulars to invade the South. Not long after, in accordance with the Gulf of Tonkin Resolution, Johnson deployed the first US conventional combat troops to South Vietnam, and the US formally entered the Vietnam War. Johnson's ordering of the "limited" reprisals and his escalation of the war won him support from both liberal de-escalationists who saw his reprisals as proportional to the alleged North Vietnamese attack as well as conservative hawks who sought to take a stronger stance against communism, winning him re-election in November of that year.