While I’m conspiratorializing, let’s do the other major one.
My ideas on this are a little wild, but I think Lee Harvey Oswald shot Kennedy because he was a Communist, and JFK was leading a global fight against Communism. You know, “We shall pay any price, bear any burden, meet any hardship, support any friend, oppose any foe, in order to assure the survival and the success of liberty.”
Communist=tyranny, ergo Lee Harvey Oswald=assassin. Hell, he was married to a Russian, and spent time in both the Soviet Union and Cuba.
I don’t see any reason to think he was given instructions to shoot Kennedy, but see no reason to rule it out. If there was an actual conspiracy, it was a Communist conspiracy, which was cleverly turned, as these things tend to be by even mediocre propagandists, into an attack on the very people trying to protect us from the Communists: our military and government.
Maybe I need to write a book. The market seems to be large, and this view–which would seem self evident given a shred of historical knowledge–seems underrepresented.