Why did richard nixon withdraw troops from vietnam?

There were several different reasons why Nixon withdrew troops from Vietnam including:

1) Growing protest in the US - There were several protests, like the one at Kent State, that made national news. These protests against the US government and their actions in the Vietnam War made it increasingly difficult for Nixon to keep Americans positive about the war.

2) Lack of success in defeating the Vietcong - The US military struggled to defeat the Vietnam due to their military tactics (such as hit and runs/ambushes) as well as their lack of uniform (making it difficult to differentiate between a soldier and a citizen). Nixon wanted to cut US losses, as there was no victory in sight.