Will the term “Rockefeller Republican” someday give way to the term “Romney Republican”? Newt Gingrich suggests it’s a possibility:

“It is the Nelson Rockefeller problem,” said Mr. Gingrich. “There is a natural ceiling. Rockefeller always did better in the general election run but the problem is if you don’t get the nomination you don’t get to go head to head.” …

Added Mr. Gingrich: “He’s a very likable person. He works very hard. He’s very smart. And he is a Massachusetts moderate Republican.”

As I’ve watched Mitt Romney over the course of this campaign, I’ve wondered myself what it is about him that seems to prevent him from acquiring a broad coalition of conservative support. Folks repeatedly cite Romneycare and his mercurial policy positions as reasons not to choose Romney — and both are damaging elements of his portfolio. But no candidate is without a problematic past (that was even true of Ronald Reagan!), and what politician hasn’t switched his position on something? Is it just that Romney won’t disavow his roots enough? That he won’t completely denounce Romneycare or say unequivocally that TARP was a mistake? But he’s promised to repeal Obamacare — and the only GOP candidate with credibility on TARP is Michele Bachmann. Is it that he’s disavowed his roots too much so that he seems insincere? But some of the most prominent conservatives in the country first proved their activist chops on the liberal side of the aisle (think David Horowitz, Dennis Miller, Abby Johnson, even Andrew Breitbart, etc., etc., etc.). True, those conservatives weren’t and aren’t politicians, but the point is, converts are often the most compelling spokespeople for a cause. By that logic, that Romney was ever once pro-choice, for example, shouldn’t discredit his pro-life position now: If anything, it ought to give it more credibility because he’s considered all the options.

But Gingrich’s comments make the misgivings about Romney a bit clearer. No matter how likable, no matter how hard-working, no matter how smart, he will always be perceived as a “Massachusetts moderate Republican.” First impressions are hard to overcome. Furthermore, the man just looks and sounds like a politician — at a time when political prowess seems to count less with conservatives than plain ol’ common sense. Romney knows that and has tried to capitalize on his past business experience, but he’s squeezed on either side by candidates who boast more experience than him in their respective sectors (Cain in the private sector, Perry in the public). It’s been said that Romney is helped by the fact that he’s a known quantity: This cycle, he hasn’t gone through the “brutalization” Perry did in his first few debates, for example. That is, nobody has really bothered to vet Romney much. That’s one reason he’s still a frontrunner despite his ties to Obamacare. But it also hurts him to be as well-known as he is because, well, nobody bothers to vet him. Cain’s 9-9-9 plan has drawn attention and Perry’s energy plan is frontpage news, but people mock the many points of Romney’s 59-point plan without bothering to learn what the points really are.

At this point, he’s less a moderate than a known unknown, an untested tested, a chronic campaigner who is perennially paler-in-comparison than his competitors. A Romney Republican.