o be sure, predictions of Trump’s demise have so far proven wrong—he has defied conventional wisdom, and continues to be the frontrunner in the Republican presidential primary despite controversies that would have eliminated almost any other candidate. But the trajectory of the campaign thus far, Nunberg says, means that it is more likely than not that Trump will lose the first presidential contests in Iowa and New Hampshire, then hobble into South Carolina having lost frontrunner status and ceded momentum to his competitors. If Trump loses Iowa and New Hampshire, he’ll stumble into South Carolina. “Once Cruz wins Iowa, and...