It might have been Mitt Romney’s most revealing moment in all the Republican debates. Badgered by Texas Gov. Rick Perry, who was continually interrupting him, Romney appealed to CNN moderator Anderson Cooper to reassert the rules of the debate: “Anderson?” That one-word plaint could stand for all of Romney’s straight-arrowness. It is a virtue and a curse. “Scandal” and “Romney” are two words you expect never to have to see in a sentence together. He’s every bit as upstanding as you would expect from a former Mormon bishop, a father of five and grandfather of 16. Romney is a familiar...