If I was making a purely speculative movie with total poetic licence about the Kennedy assassination the plot would be as follows.
Dulles is convinced JFK will not fight in Vietnam. A syndicate is formed with Dulles, Hoover, Johnson and the Mob. The hit team is lead by GHWB and the actual trigger pulled by Liddy and Hunt. Nixon has nothing to do with it. Strange though in real life he was in Dallas that day, even more curious the reason why?
So in my movie the syndicate frames Nixon for Watergate to prevent him from exposing them, and Bob Woodward is a CIA plant.
Wow how crazy Eh!