The far right, says Jamelle Bouie:

Romney is running for president as a right-wing Republican with right-wing ideas, and it is absurd to think that he would suddenly revert to the Mitt who governed Massachusetts. Even if he wanted to, he would first have to contend with a conservative movement that sees itself as the dominant partner in this relationship.

Scott Galupo counters:

How would the GOP, as a whole, maintain enough popularity to keep its grip on the White House and Congress? Looked at this way, Bouie’s vision of conservatives forcing Romney to impose an unpopular agenda of deep spending cuts and tax cuts for the wealthy seems farfetched. The more likely scenario is that Romney and a Republican-led Congress are going to do everything in their power to stay in power.