One of the main causes of the Vietnam War was the result of the actions of the U.S during the Cold War. The U.S aimed movements to attempt to prevent the spreading of communism. As a result, the USSR (Soviet Union) who also played a major role in WWII, came out as a strong influence on the eastern half of Europe. Despite this, the U.S started to see that the influence put on by the USSR threatened US democracy and ambitions.