In September 1901, at the Pan-American Exposition in Buffalo, a young man shot President William McKinley; by the end of the day the police and government were convinced that he was the victim of a national Anarchist conspiracy. Some sixty years later, President Kennedy and his brother were both the victims of assassins’ bullets. Yet on this occasion, the government would do all they could to deny that conspiracy might lie behind these brutal murders – even as popular suspicion spread that the Kennedy brothers were indeed the victims of conspiracy, and, perhaps, the very same set of conspirators. Maybe the government itself, the CIA or the FBI might have been involved? The paper will explore how narratives of conspiracy influenced and altered the interpretation of events surrounding these three assassinations, seeing in the shift between McKinley and the Kennedys, a profound alteration in the public life of American politics and, just as vitally, in what Norman Mailer imagined as the dream-life of the nation.