Which Country Started The Vietnam War And How And Why?

The Vietnam War is between North Vietnam and South Vietnam with US military backing. It is the north basis of nationalism to oust foreign influence "the US imperialism".

To the south is anti-communist and US to stop communism spread into South Vietnam and Southeast Asia - Truman's domino effect.

Within Vietnam the war started in 1956, when the south does not carry out National Election under the Paris Treaty held two years earlier 1954, which end French colonialism in Vietnam, Laos & Cambodia. The Paris Treaty agreement to divided Vietnam into two parts at the 17th parallel. With Communist government in the north under Ho Chi Minh and Monarch rule under Emperor Bao Dai in the south, but in 1955 President Ngo Dinh Diem deposed Monarchy rule for South Vietnam to be a republic.

The US fear of Ho Chi Minh victory in the national election - support South Vietnam not to hold an national election. The guerrillas war start to by insurgence in south Vietnam known as "Viet Cong". The US supported South Vietnam with military warfare's and advisers.

US direct involvement in Vietnam with troops started in 1965 on the false basis of 1964 the gulf of Tonkin resolution. From 1965 to 1973 US involvement in Vietnam expanded the war to modern warfare. The Vietnam War is  the longest US conflicts and the rest is history.