At the end of World War II, political and military tensions between the United States and its one-time ally – the Soviet Union increased dramatically. The U.S. perceived communism, a social, economic and political ideology encouraged by the Soviet Union and China, as a significant threat to its national security and power. Fearing communism would spread over to Vietnam and potentially Southeast Asia, the U.S. opposed the communist independence movement there.
The U.S. first involvement in Vietnam began in 1949 when they provided military aid to France in the form of military observers and weaponry in the First Indochina War under President Eisenhower. The French defeat in Dien Bien Phu led to a peace conference in Geneva in July 1954 which resulted in splitting the former French colony Indochina into three separate countries, viz. Laos, Cambodia and Vietnam. The last was also temporarily divided along the 17th Parallel into the communist North Vietnam and the anti-communist South Vietnam until a nationwide election would be held to unify the country. However, in 1956, South Vietnam backed by the U.S. blocked the unifying elections set by the 1954 Geneva Accords. To support South Vietnamese government, 2,000 military advisors were sent to Vietnam under President Kennedy – which rocketed to 16,300 in 1963. In return, Hanoi formed the National Liberation Front better known as Viet Cong in 1960 to incite insurgency in the South.
In 1964, after an alleged attack on two U.S. Navy vessels, the Gulf of Tonkin Resolution was passed by the U.S. Congress authorizing President Johnson to use military forces in Southeast Asia. The first U.S. combat troops were sent to Vietnam a year after that. The number of troops exceeded 200,000 at the end of the year and peaked at 540,000 in 1968. In the same year, a surprising and massive attack known as the “Tet Offensive” threatened U.S. position in both South Vietnam and its own country, and therefore was widely considered as a turning point of the Vietnam War.
In 1969, President Nixon proposed the so-called “Vietnamization” which gave South Vietnamese Army greater responsibility in fighting the war while still receiving American aid as well as air and naval support if necessary. However, the 1972 Easter Offensive put a big question mark on the policy’s effectiveness, suggesting that the South Vietnamese forces could not wage a full-scale war against the North Communists without considerable air power support from the U.S.
In 1970, the war was escalated into Vietnam’s neighbors as Nixon attempted to destroy Viet Cong’s supply bases to South Vietnam in Laos and Cambodia. That, however, provoked tremendous anti-war protests in the U.S. and all around the world, which had been started since the Tet Offensive and My Lai massacre in March 1968.
In January 1973, the Paris Peace Accords was signed establishing a ceasefire and allowing prisoner of war exchange following U.S. force withdrawal from Vietnam. The accord officially ended the U.S. and its allies’ direct involvement in Vietnam despite its continued support for South Vietnam until the end of the war. Eventually, the fall of Saigon on April 30, 1975 marked the end of the Vietnam War and Vietnam was reunified as a communist country.