Vietnam War: Reasons for US involvement

Between 1965 and 1973 US troops fought a disastrous war against communists in South Vietnam. In the end, the wealthiest country in the world was unable to defeat the Vietnamese fighters.

Why did the USA fight and lose the Vietnam War?

Vietnam divided

Vietnam had been a French colony. After the Second World War, Vietnamese nationalists and communists, led by Ho Chi Minh, fought against the French. In 1954 the French decided to pull out and Vietnam was divided in two. Communists took power in North Vietnam.

South Vietnam was ruled by an anti-communist leader called Ngo Dinh Diem. In 1959 the communist government of the North decided to encourage a revolution in the South. Southern communists, who had fled North, returned to fight. These forces were known as the Vietcong.

From 1954 South Vietnam depended on aid from the USA. American policy was based on the 'domino theory': the belief that because neighboring states are so interdependent, the collapse of one will lead to the collapse of others. The Americans used this theory as a justification of their involvement in foreign states, particularly in South-East Asia, which they felt were likely to be taken over by the communists.

In November 1961 President Kennedy began providing wide-ranging support for the army of the South, including some American soldiers as 'combat advisers'. He hoped that with this help Diem would be able to defeat the communist rebels. This did not happen. The Americans became increasingly unhappy with Diem.

In 1963 Diem's government further annoyed the USA by clashing with local Buddhists. With American approval, a group of South Vietnamese generals overthrew Diem in a coup in November 1963.

The Gulf of Tonkin Incident

In 1964 regular North Vietnamese forces marched south along what became known as the Ho Chi Minh Trail to support the Vietcong. Without outside help South Vietnam looked doomed. American involvement increased dramatically after a clash at sea between North Vietnam and the USA in August 1964.

An American destroyer near the coast of North Vietnam was attacked by North Vietnamese ships. No serious damage was done in this so-called Gulf of Tonkin Incident. However, the new American President, Johnson, ordered the bombing of Northern naval bases in retaliation. Congress passed a resolution giving the President power to 'take all necessary steps, including the use of armed force' in order to defend South Vietnam. After this Johnson felt he had full authority to step up American involvement in the war.