Rick Santorum would lose the general by double digits. He is not a serious contender. Period
If he is repudiated by the Republican Establishment. My problem with Romney is that he reminds me of Wilkie. The differences between Wilkie and FDR were minimal. Wilkie won more votes than had any previous Republican , but his only issue was the Third Term. What decided that election was the Fall of France followed by the Battle of Britain. Wilkie was nominated because he was an acceptable version of FDR and Taft was not.