Mitt Romney is an incredibly vulnerable Republican candidate, from his numerous policy reversals to his championing of the Massachusetts health care law that served as the basis from Obamacare. But for him to lose, somebody else has to beat him. And like Tim Pawlenty before him, Texas Gov. Rick Perry is blowing his chances to exploit Romney’s weaknesses. The defining moment in this debate may well have been the point at which Perry went on the attack against Romney for being a flip flopper. As I noted earlier, there’s a long file to choose from. And Perry had clearly rehearsed...