The Vietnam War was the longest war that America got involved in. It began in 1957 and ended in 1975. Vietnam, a small country in Southeast Asia, was divided into North and South Vietnam because some of the Vietnamese were Communists and others weren't. The North Vietnamese were the Communists and wanted to take over South Vietnam.

President Harry S. Truman felt the United States needed to help any nation that was threatened by Communists. So the United States helped South Vietnam. It has been the only war that America has not won.