Why did the USA lose the Vietnam War?

Why did the USA lose the Vietnam War?The Americans did not lose purely for military reasons. There were other factors as well.Write an explanation AND cite a source which shows the importance of the following six factors:
1. US military tactics in Vietnam
The US could discifer the Viet Cong so they ended up killing many innocent civilians including women and babies. Also inexperienced soldiers walked into traps. source 44
2. The unpopularity of the South Vietnamese regime
They were unpolular because people thought they were murdereders and hated their tatcics of how they killed innocent civilians. This made many people not wat to join, source 46
3. The experience of the Viet Cong and the inexperience of the American soldiers
The Viet COng and their tactics was enought to defeat the Americans even thought the Americans outnumbered them. source 39
4. Domestic opposition to the war in the U.S.
The domesctic oppostition effected them becuase that was a little less support that they got.
5. Chinese and Soviet support for the Viet Cong
The communists supplied the Viet Cong and they were very close by.
6. 'But did they really lose?' Summarize the argument put forward in Source 57, and your view on it.
I agree that the South Vietnamese lost the war. We left and left the war up to them, who we had just been helping int he beginning and they lost it themsleves. yes, they probbably lost becuase they didn't have our help anymore, but it was not our war it was theirs.