The reason behind the us entering the Vietnam War was a general attempt to prevent Communism.
Communism although good in theory particular for the masses, doesn’t always work.
Sadly it doesn’t work as it is human nature for people to be greedy, the leaders are generally better off and ordinary people don’t normally work harder without incentive.
Throughout the 1950’s and 1960’s many countries adopted a communist government, including Vietnam or as it was known then French Indochina.
In America in the late 40’s the fear of Communism became increasingly prevalent with people believing that Communism was taking over the world, the us felt that it was losing the cold war and wanted to stop Communist talking over.
In Vietnam during the 1950’s and early 1960’s the French who were the colonial power were fighting to maintain control of the country and to regain national pride after being conquered themselves in world war 2 by Nazi Germany, the French were less concerned about communism than the Americans.
It became clear that the French were losing the war in Indochina and eventually withdrew from the country in 1954, fearing that the communist North Vietnam would take over all of Indochina and possibly south East Asia the us began sending ever increasing war materials and aid the capitalist Vietnam.
Why Did the US Enter the Vietnam War: the capitalist south Vietnamese were losing the fight against the communist north Vietnamese and Americans feared the communists would take over.
In 1959 American military advisors were authorized to fire back if fired upon, by the mid sixes the United states were deploying combat troops reaching a height of 543,000 troops in 1969.