Just read a book on Eisenhower, and how he was adamant not to involve us in a jungle war beyond the very limited role of 500-600 combat advisors. Kennedy came in talking like Mr. Tough Guy who had to stand up to the Russians/communism to change his image of a lazy rich kid who never did much in the House or Senate, got us involved deeper and deeper to the point where Johnson could easily make the next stop toward major involvement.
The book sees Eisenhower's farewell speech, not just the military-industrial complex portion, as a warning to Kennedy, which he and his band of Ivy League elitists (who the author terms a bunch of "don't worry, we got this" kids who were in over their heads) ignored.
Easily one of the stupidest and most costly examples of American foreign policy in any century, and one so avoidable had Kennedy/Johnson's war hawks listened to others who saw it for what it was, an anti-colonialism civil war. Instead they bought into the stupidity of the domino theory.