The amount of money that the defense contractors got for supplying the Vietnam War was staggering. If it was true that Kennedy wanted to withdraw and avoid the conflict, then that is a very real motive to get rid of him.

Of course, Kennedy was not a real supporter of the CIA in view of the advice they gave him concerning the Bays of Pigs fiasco. He ended up getting rid of Dulles at the CIA, and guess who ended up as a member of the Warren Commission - Dulles.

The mob had it's motive, with RFK putting the heat on Hoffa and Giancana like he did. And obviously Castro would like to see him gone after the attempts on his life, the Bay of Pigs, the missle crisis.

I don't think we will ever know the real truth.