The Vietnam War
The Vietnam War was the longest war the United States ever participated in. The US was working with the South Vietnamese to overthrow the Communist Government of North Vietnam, but was unable to succeed. Fighting had already been going on for 11 years prior, known as the first phase. The Vietnamese were fighting the French Government for control of Vietnam. They were victorious in 1954, at which time Vietnam was then split into North and South Vietnam.
USA entered into the battle, based on the “Truman Doctrine”, which declared the United States must help any nation challenged by Communism. It was generally feared of one Southeast Asian country joined with the Communists, others would follow, creating a domino effect and empowering the Communists. The United States remained in the war until January of 1973, when a cease-fire agreement was signed. American troops were withdrawn within 2 months. Fighting resumed, but US troops did not return. South Vietnam surrendered April 30, 1975.
The United States involvement in this war is still a hotly debated topic. Even today, Americans are split in their opinions of the handling of our participation in this massively destructive war.