"Anyone From Vietnam Era Remember" I enlisted for flight school  

 I enlisted for flight school ASAP, agreeing to take the first open seat.

1968 was the year that we, that is South Vietnam, USA and allies lost that war. Militarily, the communists attacks were suicide, stripping themselves of their core of well trained and motivated troops and hard to replace material.

Psychologically, America was crippled. We had been told for months that the communists were losing large. 
Then Mini Tet happened, a another well planned and disciplined operation, further discouraging Americans. Obvious propaganda at those points. The communists, VC and NVA had the initiative and would use it to telling effect. 

1968 was the peak of US troops in Vietnam, declining annually until we formally just went home. In the end, America stopped supporting South Vietnam, allowing the North to exploit weaknesses in the South Vietnam military.

Contrary to general perception, the South Vietnamese military was generally effective, but lacked the strategic initiative that would gave allowed them to pick where and when to fight. The Cambodian excursion was a success as far as it went.

There is no winning a civil war for another country. The end of that war was inevitable when we resumed the French strategy.