In a preview of what will certainly become a central argument of the Obama reelection campaign, the American Prospect’s Jamelle Bouie says that Mitt Romney will serve at the pleasure of the Republican party’s rightwing base:

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. … If conservatives expect to set the agenda — and if Romney, as president, wants to maintain their support — then he can’t govern from the center. Nor does he plan to.

My opinion of Romney is as low, perhaps lower, than Bouie’s. But I think he’s hanging his speculation in the wrong frame.

On the one hand, yes: Mitt Romney is quintessentially the kind of guy who enters politics in order to be something, not do something. In this respect, it’s easy to imagine him dangling on the strings of his puppet master.

Much as a general election campaign is fundamentally different in nature than a primary campaign, things change once a party gains power on both ends of Pennsylvania Ave. The grenade-throwing backbenchers are wrangled and pressed into good-soldier service. The national party committees become more closely aligned with the internal communications staffs in the White House and congressional leadership offices. Partisan pollsters and focus-group maestros package weekly messaging hymnals that everyone’s supposed to sing from on the Sunday-morning public affairs shows.

Bouie imagines that the right wing of the party is going to drive this agenda, and that Romney will in effect march like just another good soldier.

But rather than try to anticipate how a Romney administration will interact with conservative Republicans in Congress, why not step back and ask a different question: 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.

In practice, I think this means we could see stimulus measures that are called something other than “stimulus”; a proposal to re-close the “Donut Hole” in Medicare’s prescription drug program if ObamaCare is struck down by the Supreme Court; and, lest we forget, Medicare reforms that conveniently exempt everyone age 55 and over.

In short, liberals are dreaming (nightmaring?) if they think Republicans are going to position themselves far out of step with public opinion on budget reform and taxes. The Romney administration is going to look a lot more like Bush’s third term than Goldwater’s imaginary first term.