<p>Presidential campaigns—like genre fiction—tend to conform to a simple set of rules and tropes. </p><p>Reporters keep the vigil for a longshot candidate that’s about to catch fire. They bird-dog the front-runner’s campaign for signs that he’s stumbling. “Establishment” candidates are cast against “outsider” and “insurgent” candidates. Other checkboxes: In almost every campaign, a young candidate calls for generational change, and he is usually pitted against the aging political stock of vice presidents, losers in previous presidential campaigns, and members of political dynasties, all of whom brag about their experience.