Mitt Romney is a Mormon, and that makes evangelicals unhappy. Mitt Romney implemented a form of Obamacare in Massachusetts and that makes conservatives unhappy. When Mitt Romney was a senatorial candidate and while he served as governor, he was effectively pro-choice, and that makes Republicans unhappy.
So, what's a country club Republican like Mitt to do? Well, one of his supporters has written a letter to Republicans basically asking them to forget Romney's background and previous positions because he can raise a buttload of money.
While I don't doubt Mitt Romney will once again set records for the expenditure : delegates ratio in both parties, I don't see this working. For all that the business side of the GOP may like Multiple Choice Mitt, he's just too much of a slicky boy for the religious right base.
Also, he's cruel to dogs.