Last month, during a Republican debate, Ron Paul was asked whether he promised to support the GOP nominee next year, no matter who emerges from the primary process. “Not right now I don’t,” Paul said, “not unless they’re willing to end the war and bring our troops home.” Apparently, in the ensuing weeks, “not right now” has become “no.” Paul called his Republican presidential rivals, including frontrunner Rudy Giuliani, “neo-conservatives” whom he couldn’t support in the general election should his own bid fail. “They think we’re supposed to spread our goodness through force,” Paul said. For example, none will pledge...