Although trouble had existed in Viet Nam long before the US became involved, the Kennedy administration marked the beginning of America's role in SE Asia. Kennedy sent advisors to Viet Nam, but it was his successor, Lyndon Johnson, who initiated full US military involvement in 1963. The war was extremely unpopular on the home front and led to massive war protests, draft age young men fleeing to Canada and an extremely misguided attitude of anti-war protestors toward returning American military personnel.
President Nixon cut back on US troop involvement, but slow progress in bringing the war to an end, escalated protests and Viet Nam became "Nixon's War" to the liberal protestors who seemingly forgot the President Johnson had involved the US in an unwinnable, unpopular war. The war would come to an end during the Ford administration when Saigon fell in April 1975.
For more see: https://en.wikipedia.org/wiki/Vietnam_War
Family connections: None. I was of draft age during the war and attending college, thus granted a student deferment. Vision technology had not progressed to the point where light-weight, strong eyeglasses had been developed. I imagine my vision would have warranted a 4-f classification.