Stuart Stevens was the chief strategist for the Romney presidential campaign. Over the years, one of the more troubling characteristics of the Democratic Party and the left in general has been a shortage of loyalty and an abundance of self-loathing. It would be a shame if we Republicans took a narrow presidential loss as a signal that those are traits we should emulate. I appreciate that Mitt Romney was never a favorite of D.C.’s green-room crowd or, frankly, of many politicians. That’s why, a year ago, so few of those people thought that he would win the Republican nomination. But...