At its core, it was a battle between Democracy and Communism fronted by surrogates with South Vietnam , Australia, New Zealand, South Korea, Thailand, the Philippines and the US representing the former, and North Vietnam, China and the USSR standing in for Communism.
You also can't forget the Hmong, who fought against the Northern Vietnamese. The Hmong allied with the US.
The Cold War.
An agreement made by opposing sides in a war to stop fighting for a certain time; a truce.
The Vietnam War was one of the worst in American history. Combat in the jungle was difficult, and it was hard to know who exactly was the enemy, since Vietnam had two different sides of the war as well.
The simple answer is that they did not win the war for either side, nor establish an actual moral superiority between the opposing sides.
Suggest: Statistics About The Vietnam War. Recommended by the History Channel.