The American strategy in the Vietnam war was to increase the body count by killing lots of Viet cong to scare the Vietnamese into removing the communism.
America didn’t have the political will to stay in Vietnam because we were losing so many soldiers and because people realized we didn’t have any type of control of the situation in Vietnam. Which is why we weren’t able to rid Vietnam of communism
The soldiers thought that the war was a unstable political mess that really had no chance. They would see some of the tech the Vietcong had since they were partnered with Russia they had more high tech weapons which made them think that we were getting ripped off by the government since in Washington had really no clue about what was really going on in Vietnam
The Vietnamese strategy of warfare was guerilla so they went around killing innocent villagers to show their power since they were 100% supported by their government.
If Persia had won the battle of marathon then America probably have democracy or alot of the things we get from them like schooling. Also Greece would probably have got overrun and taken over by Persia destroying the Greek name and what was known about the Greeks.