When former Florida Gov. Jeb Bush announced that he would “actively explore the possibility of running for president of the United States,” America’s legion of political junkies didn’t exactly jump for joy. On the contrary, many of them — especially if they are conservative or libertarian-leaning activists — rolled their eyes, sighed with world-weary despair, or simply fell into a spell of gentle, quiet weeping. “If Jeb Bush is the nominee,” best-selling author Brad Thor announced, “I will never vote Republican again.” On Twitter, writer Ben Shapiro lampooned the “GOP geniuses” behind the Jeb push: “In 2012, the top issue...