I continue to believe that the Soviet regime was behind Kennedy's murder. The early sixties (the period of Fail-Safe and Seven Days in May) was the only time in the Cold War that a president's murder could actually have helped the Communist cause; in fact, the Soviet leaders had reason to hope that it would plunge America into civil war. The weakness of the plan, as always, was the human factor. If the MVD or GRU had found an assassin with conservative credentials, they would have been home free; but evidently they couldn't. They had to settle for the defector Oswald, who was at least a white American.
I recall (does anybody else?) that Earl Warren actually said that there were things about the case that might not be revealed in our lifetime. Why not, unless for fear that the revelation would bring on World War III?