Running for office requires particular skills, and success in other fields does not necessarily carry over to the campaign trial. Consider retired Gen. Wesley Clark. On paper, he was a dream candidate: West Point valedictorian, Rhodes Scholar, combat veteran of Vietnam with a Silver Star, White House Fellow, commander in chief of the US European Command. But after he announced his candidacy for the 2004 Democratic presidential nomination, he bobbled questions that an experienced politician could easily have anticipated. Would he have voted for the Iraq War? “I don’t know if I would have or not,” he said. “Mary, help!” he called to his press secretary, when reporters bore in. “Come back and listen to this.” He got a little better over time, but never quite got the hang of presidential politics, and his campaign fizzled…

Even very famous people are often unready for the scrutiny that comes with a presidential race. Billionaire H. Ross Perot had first gained national attention in 1969, when he tried to bring Christmas presents to American prisoners of war in Vietnam. In 1992, he initially got a great deal of support when he announced his campaign for the presidency as an independent. At one point, he even ran ahead of both Gov. Bill Clinton and President George H.W. Bush. But then his eccentricities came to light, and he became unhinged. Among other things, he accused Republicans of a bizarre plot to disrupt his daughter’s wedding. He defiantly underscored his oddness with his choice of an official campaign song: Patsy Cline’s “Crazy.” Though he ended up with a substantial share of the popular vote, he did not win a single electoral vote.