The commonly accepted dates for the Vietnam conflict are 1954 to 1975. Most of the military fighting occurred between 1957 and 1973. Because Congress never officially passed a vote to declare a war, the United States was never technically at war with North Vietnam.
Vietnam was divided as the result of a treaty ending the Korean War. According to the original provision, it was to be re-unified a couple of years later. However, Dwight D. Eisenhower helped the southern half of the country organize into a new nation. The anti-communist South Vietnam, backed by the United States, engaged in a military confrontation with the communist North Vietnam until 1973, when the United States withdrew its troops. Two years later, Vietnam re-unified under communist rule.