Americans adore irresponsible, flashy celebrities. But they do not vote for them. Michael Jackson’s funeral crashed the Internet. Had he ever tried to run for dog-catcher, it would have been a very different story. Sarah Palin is about to experience the weight of this rule. Between her speeches and her book deal, she can reasonably hope to earn $10 million over the next two years. She’ll fly in private jets, sleep in sumptuous hotel suites, receive rhapsodic applause. Yet there will be no escaping another story line. Faced with exasperating criticism and the accumulating cares of public office—she quit to...