Instead of emerging as the inevitable candidate, the former governor finds himself in a Republican primary field of eight, and it could billow to as many as 15. Among the already declared is Marco Rubio, the freshman senator from Florida and one of Jeb’s former protégés. Jeb has underwhelmed the base — in Iowa, he polls in seventh place — and revealed himself to be far less polished on the hustings than his supporters had anticipated, particularly when answering questions that force him to navigate between family loyalty and a rational foreign policy. His one job above all else was to distinguish himself from his father and his brother, who rattle about Jeb’s campaign like a pair of unzappable ghosts. Yet when Fox News’ Megyn Kelly asked him whether he’d have supported the Iraq War, knowing what he knows now, the governor’s whiffing sequence of answers made clear he’d only thought through how to distinguish himself personally from his brother — by telling the story of his marriage, mainly, to a beautiful Mexican woman he’d met in León when he was still a high-school teen — but not politically.

Anyone who’s familiar with Jeb, though, doesn’t seem nearly as fixated on this episode as members of the national press corps. They know that freestyling is his natural political mode. As governor, Jeb genuinely enjoyed mixing it up with local reporters, almost always fielding more queries than his staff would have liked. “He’d do a five-minute gaggle” — mediaspeak for a mini press conference — “and you’d get five stories,” says Adam C. Smith, the political editor of the Tampa Bay Times. “He’d think out loud, he liked to banter. Compared to Charlie Crist, who never said anything, he was fun to cover.” But now, it seems, the very qualities that served Jeb well with the Florida press — spontaneity, authenticity — are serving him poorly on the national stage. Which is a shame, in its way: One of the pleasures of being around him, day to day, on the stump, is his enthusiasm for speaking off the cuff. (And I report this, it should be noted, as a person who agrees with exactly nothing the governor says.) ...