I am writing an essay on My Lai and as an Introduction I need to write a short paragraph on the Vietnamese War. Any help would be appreciated!

Hey everyone,

I'm writing an essay on the Watergate scandal and I have to talk about the Vietnam War since it leads to the Pentagon Papers and the eventually cover up of the burglary to steal those papers.

I came across a section in a book that reads Cambodia was a neutral territory but before it states that the North Vietnamese had "safe" havens inside the country.

Could somebody please help me understand this? Thanks in advance.