In 1955 when France pulled out of Vietnam the U.S felt like they had to take action in order to prevent South Vietnam from falling into Communism. Starting in 1955-56 the U.S started to send military advisors to assist the South Vietnamese army. The U.S was worried that Ho Chi Minh, leader of the North Vietnamese Communists would try to unify Vietnam under Communist rule. At this time president Truman viewed Communism as the greatest post-war threat and was worried about the spread of communism in Vietnam. Truman believed that the U.S should be world police and prevent the spread of communism. As the U.S tried to fight against the spread of communism the power of Communist rebels in South Vietnam kept increasing. As a result president Truman felt obligated to send more and more military advisors until finally in 1965 Truman sent a large number of American combat troops into Vietnam to prop-up South Vietnam. This war was obviously between North Vietnam, supported by its communist allies, and the government of South Vietnam, supported by the United States of America and other anti-communist countries. The United States played a big role taking the side of the South Vietnamese army but failed to have the support of the American people. The involvement of the United States into the Vietnam War was obviously not justified for many reason which I will talk about in the following. Since the American people didn’t support the U.S getting involved in war with communist North Vietnam it clearly went against and interfered directly with people’s pursuit of happiness. As well Americans believed that the intervention in south Vietnam interfered with the “ Self-determination” of the United States. According to the United States, the pursuit of happiness is defined as: "...one of the "unalienable rights" of people enumerated in the Declaration of Independence, along with "life"