After the end of the Second World War, the Allies wished for France to be a major world power. The immediate reason for USA switching sides therefore was to re-establish French influence in its former colony as a means of containing communism in the region. This policy ran into problems following the declaration of Vietnamese Independence by Ho Chi Minh, the leader of the Viet Minh in September 1945.
The reimposition of French rule in Vietnam was bound to lead to conflict with the Viet Minh and France soon became embroiled in a guerrilla war. Despite being provided with substantial financial aid by the USA during this period, the French suffered a humiliating defeat in 1954 at Dien Bien Phu in the north of the country.
Under the Geneva Accords of 1954 it was agreed between the major powers that France should leave Vietnam which was divided into two. North Vietnam became communist under Ho Chi Minh and South Vietnam became non- communist. This proved to be an unsatisfactory solution in the short term even though elections were promised in both North and South, with a view to uniting the country.
Fighting broke out in the South. With the departure of the French this only left the USA to stop the spread of communism and therefore led to its increased involvement in Vietnamese affairs.
The USA became involved first in the political situation in Vietnam by forcing South Vietnam not to hold elections for fear of a communist victory. Instead the USA set up a new government under Ngo Dinh Diem who made himself a dictator and became increasingly unpopular. His government was corrupt and brutal and he was a Roman Catholic ruling a Buddhist majority. Diem also refused to hold elections in the South because he thought the communists would not allow free elections in the North. Diem’s unpopularity was the most important reason in the short term of continued US involvement as more South Vietnamese turned to communism and against the USA, causing more tension with the North.
As the American political move proved unsuccessful, the North felt the time had come to unite Vietnam by armed force. It sponsored the creation of a communist organization in the South called the Viet Cong which used the same guerrilla tactics against the American sponsored government that had been used previously against the French.
Successive American presidents, who repeated pledges that America would defend freedom around the world, were therefore drawn in to giving more and more money, equipment and military aid to South Vietnam. Kennedy for example was forced to send military advisors to train and direct the South Vietnamese Army in how to counteract guerrilla warfare. As the support for the communists in the South grew, American involvement escalated. By 1963 when Kennedy was assassinated there was 16,000 US military advisors in South Vietnam but despite this assistance, South Vietnam seemed on the verge of collapse.
In spite of the military commitment, Kennedy maintained he was determined that the USA would not ‘blunder into war, unclear about aims or how to get out again’. His successor Lyndon Johnson was more prepared to commit the USA to a full scale conflict to prevent the spread of communism. He recognised that the current strategy was not working and to pull out would have showed America to be weak. He also needed to show he was a strong president in order to be re-elected so his only option was to increase involvement by sending combat troops rather than advisors.
In August 1964, the Americans exaggerated a minor incident in the Gulf of Tongking when a US destroyer supporting the South Vietnamese was reputedly fired on by North Vietnamese patrol boats. Following this incident the US Congress gave Johnson overwhelming support to take all necessary measures to prevent further aggression and achieve peace and security. This gave him the authority he felt was needed to justify taking direct military action.
In March 1965, 3,500 US marines landed at Da Nang which meant that America was at war in Vietnam and by December 1965 there were 150,000 troops stationed in the country.
The domino theory of the spread of communism convinced America that a stand had to be made somewhere and that place was Vietnam. Once the political solution had failed through the unpopular Diem government, the escalation of American involvement from financial aid and equipment to full scale military involvement was inevitable.