11. LBJ Did It
The relationship between Jack Kennedy and his Vice President was a contemptuous one, to say the very least. Lyndon B. Johnson's personality was recently described as one of "grandiose narcissism," and his pick as Vice Presidential candidate, some say, was strictly one of strategy to win Johnson's home state of Texas in the 1960 election. His presidential aspirations were also no secret, which likely also fuels the fire of his most critical conspiracy theorists. Also fueling the fire of this speculation is the fact that a 2003 Gallup poll reveals that about 20% of Americans believe that Johnson was directly involved in the assassination of President Kennedy; to make matters more interesting, rumors have circulated for quite some time regarding phone recordings of Jackie Kennedy apparently pending release that allegedly indicate her suspicions of Johnson's involvement in her husband's murder. Again, this is all speculation at this point. Doubtful as this one is and while LBJ was far from the most popular President because of his escalation of the Vietnam War, any real credibility towards this hypothesis likely died with Johnson in 1973.