Conspiracy theories, rampant in the United States, have an unusual power to motivate people to action. Some conspiracy theories are associated with various right-wing or left-wing ideologies, while others transcend ideology, like those surrounding the 9/11 attacks or the assassination of John F. Kennedy. Under the right circumstances, such theories can motivate people to violence, especially if the conspiracy theories single out specific people or organizations as the villains. Most extremist movements develop or depend on conspiracy theories to some degree. In the United States, extreme right-wing movements have a particularly close relationship to conspiracy theories.