Bill’s cool and Barack’s an uptight prig. Cue the laughter. Bring on the guffaws. But wait — didn’t we already know that? It’s easy enough for conservatives, libertarians, et al, to gloat about Barack Obama’s recent petulant, child-like performances — at first unable to be even slightly gracious in compromise with Republicans on the tax bill and then, only a few days later, fleeing in panic when Clinton acted the real president, fielding questions with a relaxed authority so surpassing Obama’s it was almost comical. But there is a bigger reason not to gloat. We are stuck with this odd...