A lot of conventional wisdom suggests that Mitt Romney is almost sure to be the Republican nominee for president in 2012. He's consistently been at or near the top in national polls. He looks and sounds presidential, he's raised a lot of money, and of Republicans actually running (which rules out Christie, for example) and with a realistic shot at getting nominated (sorry, Ambassador Huntsman), he probably has the best chance of winning the general election.
But at the same time, Romney been consistently polling well under 30 percent, in fact rarely breaking 25% (see Gallup for example). In the latest polls her comes in behind Herman Cain. Moreover, conservative support is currently split across the rest of the field, but as a group, Cain, Perry, Bachman, Gingrich, and Santorum outpoll Perry by about two to one. As the lower-tier candidates inevitably start dropping out, it's unlikely Romney will prove to be the second choice of many of their supporters.
So who is likely to wind up with those votes? Josh Marshall of Talking Points Memo quotes two TPM readers, JR and WB, who offer good reasons to think it's Rick Perry. In brief, Perry is way ahead of everybody else except Romney in terms of political infrastructure and fundraising, and while Cain's current polls are impressive and he's proved an inspiring speaker, he has very little in the way of a campaign organization.
I'd been thinking along similar, if simpler, lines myself: Hard-core conservatives want anybody but Romney -- someone who accepts evolution, until recently backed Planned Parenthood and the rights of gays and lesbians, and runs away from his one notable political accomplishment was, namely introducing health insurance reform in Massachusetts that served as the model for what the right calls "Obamacare." While Cain can't be ruled out, he's never held elective office, and Perry has a huge advantage in terms of establishment support.
Santorum, Gingrich, and Bachman are such long shots I'd expect them to drop out early on as their funds run out. Huntsman is another one unlikely to hang on, though his relatively tiny number of relatively moderate supporters are more likely to go to Romney or even Paul than Perry or Cain.
That leaves Ron Paul, who is a breed apart. His supporters are harder to classify on a moderate-conservative axis, and he's got enough backing that he's likely to stay in the race for a while no matter what, despite his low poll numbers.
So there's a fair chance that conventional wisdom as of a couple of months ago had it right: It's likely to come down to Romney versus Perry, with a large fraction of Republicans preferring Perry's politics but Romney's electability. Who gets nominated may well depend on which consideration they deem more important.