Question

When was South Vietnam reunited with North Vietnam as a single communist Nation

Answer 1

When the US left.

Step-by-step explanation:

The answer is simply, when the US withdrew from Vietnam. They did NOT become democratic or capitalists, they remained communists.

Answer 2

Vietnam was divided by the 1954 Geneva Agreement that followed the French defeat at Dien Bien Phu. The last Americans were withdrawn from the South on April 30, 1975, following the Communist victory over the Saigon forces supported by the United States.