Surely by now you’ve figured out that you shouldn’t be listening to any of us, haven’t you? One of the more nitwitted arguments of Marxist-Leninists—back when there were such people—was that history is a science and human behavior is as predictable as chemical interaction, rendering sociological results inevitable,; and if few of us in what passes for the commentariat these days would put matters in such a way, we still tend to view politics as a series of patterns determined by previous patterns, which are defined by ideology and demographics. Intangibles, X factors, monkey wrenches in the machinery—or, in other words, human beings acting like human beings—get lost in the accounting, and sometimes the result is a conventional wisdom that not only proves wrong but also didn’t make sense in the first place. To argue that this election is about demographics suggests major blocs congenitally programmed to support one candidate or another: Naturally, for instance, young people are going...