President John Fitzgerald Kennedy assassinated himself in order to create a time paradox that would unleash enough energy to banish the Greys/Lams back to their home dimension. Vincent Price and Christopher Lee joined forces to cast the magic silver bullet that JFK fired from Elvis Presley's old army rifle.
He then retired to an island in the South Pacific with Marilyn Monroe, who faked her own death so they could be together.
Now you know.