Answer:
Officially the Vietnam was lasted for 20 years. The US became involves on the 8th of March 1968. After the Second World, a cold war was declared involving The USSR and the USA. Essentially, this was a battle involving communism and capitalism. In the Truman Doctrine, the US let the USSR know that it hated communism. Right after WW2, Russia wanted Germany to suffer for the 20 million soldiers which had lost their lives in WW2. The US were keen to redevelop Germany and create a fair economy. The US wanted to contain communism and stem its spread. In the case of Vietnam, the North was Communist and the South was Capitalist. The US thought that if South Vietnam fell, then so would its neighbouring countries. That is why America became involved in Vietnam
