With the anniversary of President Kennedy's death coming up, it made me think of a theory as to why there were so many assassinations and attempts during that period of American history (JFK, RFK, MLK, Malcolm X, and Lennon all died, attempts made on Wallace, Ford, and Reagan).
It's been theorized that one of the causes of today's mass shootings are copycats. With that in mind, is it likely that some kind of "Oswald effect" drove much of it, or was it due to unique circumstances that it happened in the same era?