See "Gore, Albert" and "2000 Election" as an additional illustration of how this worked from the other side. That guy was running as the incumbent vice president under Bill Clinton, and he had so thoroughly sold his soul in politics that he couldn't even carry his home state (Tennessee), or even Clinton's home state of Arkansas.
Close to 4 million conservatives stayed home because he was a moderate. I think he ran a real good campaign as well, but evidently these 3+ million warned after McCain that they would do this if a conservative was not put on the ticket. They did it. I want them back
Maybe Romney shouldn’t have been the nominee, but nobody that ran would have done any better. Rick Perry probably had a better message and all three legs of the stool, but he probably should have waited until he was done with the pain meds before he jumped in. Now he is damaged permanently. Santorum had the social conservative leg well entrenched, but like Huckabee, has a poor record on the budget. Team Obama would have had a field day, and he also would have lost the “woman” vote by about 65-35.