The reason that the Vietnam War was started was that North Vietnam wanted to take over South Vietnam and turn it into a communist country, and South Vietnam fought back, wanting to stay under a non-communist rule. The U.S. joined in because North Vietnam ousted the French from what was French Indochina. The French were backed by the U.S. and when North Vietam wanted to take over South Vietnam, the U.S. committed to protect South Vietnam as a U.S. puppet state and as a containment policy to stop the spread if communism. Also North Vietnam and the Viet Cong wanted to make both Vietnams one country again.