Question

Why was the Vietnam War such a different conflict that the United States had ever experienced up to this time in history?

Answer 1

The U S failed to recognize that the Vietnam was a civil war and most of the wars in which we engaged most notably WWI and WWII were wars based on one country's domination over another. Ostensibly we fought the Vietnam War to keep the southern part of the countrytenuously democratic but with rigged electionsfrom becoming part of the communist north. At the time the U S had a treaty obligation under SEATO Southeast Asia Treaty Organization 

Answer 2

The Vietnam war was one of the first wars that the American public didn't support. Vietnam soldiers and veterans were demonized in their own country. This had a negative affect on our soldiers in Vietnam. Moral dropped, not that it was that high in the first place.

Vietnam was an awful experience for the soldiers in it. If a soldier entered a village, he could be attacked by anyone, even by a small child. And, in the jungles, there were mines and other types of lethal traps everywhere. Soldiers learned to walk in the footsteps of the guy in front of them so they didn't risk setting of a hidden explosive.
All of this contributed to an insane amount of PTSD.