Kennedy had a more pacifist approach to politics than some people would have liked. Some people? Yes, some people. Kennedy didn't invade Cuba, he basically wanted to make peace with the USSR and go to the moon together, and upset "some people". Richard C. Hoagland has by far the most interesting theory on the Kennedy assassination: he thinks Nazis killed him. Nazis you say? Yes, the Nasa Nazis, who, by definition, had no desire to work with Communists. Crazy you say? Yes, but probably not as much as you think. Through Operation Paperclip, Overcast, and the rest, thousands of Nazi scientists were taken out of Germany to American soil, including the famous Wernher Von Braun (Nasa director) who once was no less than an SS officer. Hoagland argues that both Communist Russia and Capitalist America knew of ancient ruins on the moon, left there by, yes, aliens, and that the space race was all about getting to this abandoned technology first. Kennedy, says Hoagland, wanted to go there together with the USSR. This much is attested by other sources, though minus the ancient alien ruins, naturally. The Nazi presence is another big topic and I won't go into it, except to say that Jim Marrs wrote a book about it called Rise of the Fourth Reich and that one of his books was the basis of Oliver Stone's movie on the Kennedy assassination, Crossfire: The Plot that Killed Kennedy.