My grandfather went to Vietnam in 1966. It was just the beginning of American troops moving into Vietnam. The Gulf of Tonkin Resolution gave the president the authority to put troops in Vietnam when ships were attacked. My grandfather was a lieutenant in an engineering company repairing combat vehicles and other heavy equipment. He was on a promotion board to help promote others to higher ranks. There were a lot of supply problems and he was sent on special assignments to fix them.
Also the political environment in history involved the 1965 Voting Rights