After World War 2 had ended France came back 2 Vietnam expecting to take control of the country as before the war but Ho Chi Minh wasn’t going allow France to allow France to rule the country again so the Viet Minh went to war with France to fight for its independence. At this time the USA were sympathetic and saw it as a poor country trying to fight off a larger more powerful country.
In 1949 who shares a border with North Vietnam turned communist this concerned the USA as it thought China would be on the communist side with Ho Chi Minh who would fight capitalism across the Asia this was called the domino theory the idea was that as one country fell to communism the neighbouring country would also fall like a row of dominoes.
The Americans did not want this to happen so they had a policy of containment the idea of this was to stop the spread of communism this also tied in with the Truman Doctrine these factors lead to the USA giving money and military advisers to France to fight the communists.
The war between France and the Viet Minh ended with the French being defeated at Dien Bien Pu in 1954 and the 17th parallel became a boarder between the communist south and the capitalist south they agreed that elections would take place but the USA prevented these elections because of fear that the communists would win.
War broke out between the communist north and capitalist south the USA continued to send money and weapons but it was inevitable that the communists would win because China and the USSR were supplying North Vietnam also South Vietnamese citizens were Buddhists and the government was catholic this and the government being evil led to them joining the Viet Cong which were fighting against its own government.
In 1964American war ships got attacked in North Vietnam waters by patrol boats. This lead to the Tonkin Gulf resolution this gave president Johnson the power to wage war on Vietnam when the resolution was signed only one politician was against the resolution.
As a result of this the Vietnam conflict began in March 1965 when 3500 us marines landed at Da Nang these are all valid reasons why they went to war the reason I think is most important was the thinking behind the domino theory as the USA thought that the whole of Asia could fall quickly and more than half the worlds population could be communist.
