Vietnam was considered as the part of INDIA and CHINA. This area was dominated by the French, Strong national movement started in Vietnam against the French dominance. During the 2nd World War, Vietnam was captured by JAPAN. After surrender of JAPAN, the French forces came back to recapture Vietnam and establish its dominance once again. These series of events triggered the Vietnamese National movement and it was lead by the famous Communist leader Ho Chi Minh, who was fighting with the support of peoples army called Việt Minh Front.
In 1954 French forces were defeated in the famous battle of Dien Bien Phu. In the same year Geneva Conference was convened, in which the decision was taken to divide Vietnam into two parts and later to conduct elections to decide about the Unification.
The southern part of the government which was supported by the US denied to go for elections and when people unrest triggered against the government, the government tried to suppress it with the support of US military forces. But the nationalist sentiments of the people were much stronger , which helped them to give a tough resistance against the forces through Guerilla warfare.
Moreover, this was the time US government was domestically and internationally isolated. By 1975, US started to withdraw its forces and in 1976 Vietnam emerged as an Independent and Unified country.