On a list of some of the world’s best-known conspiracy theories, Americans are most likely to believe the one about JFK‘s assassination. But President George W. Bush and President Obama don't escape suspicion.

A new Rasmussen Reports national telephone survey finds that just 45% of American Adults reject as false the theory that President John F. Kennedy was assassinated by more than one shooter. Thirty-two percent (32%) believe more than one shooter was involved in the 1963 assassination in Dallas, and another 23% are undecided. (To see survey question wording,click here.)

Last November, on the 50th anniversary of the assassination, 36% of adults said Kennedy was the victim of a lone gunman, but just as many (37%) said he was the victim of a larger conspiracy.