JFK's Assassination Prompted by Film?

Amongst the hundreds of theories surrounding the assassination of JFK's assassination, one stands out to me as perhaps one of the most interesting (if not the most far fetched).

The connection between Lee Harvey Oswald and "The Manchurian Candidate" directed by John Frankenheimer, has been cause for great speculation. The film follows an American soldier who is brainwashed by Communists to assassinate an American presidential candidate. This theme has an eerily similar plot line to the real life assassination of JFK and some have claimed that the script provided a blueprint for Lee Harvey Oswald's actions. The film played for a full year next to Oswald's post office and it has been calculated that he saw the film on more than one occasion. Some claim he saw it "numerous times" and developed an infatuation for its political plot. The film was pulled from theaters soon after the assassination due its creepily similar motif.

Any validity behind this? If so, can films be held responsible for the actions of others? Let's hope not...