The race for the Republican nomination may be coming down to Newt Gingrich and Mitt Romney, but in the contest for the Iowa caucuses, their high-profile battle might still turn out to be a sideshow. The national party has spent the last two weeks resigning itself to a choice between the former speaker and the former Massachusetts governor. But Iowa Republicans may end up choosing between Gingrich and Representative Ron Paul.

In every post-Thanksgiving poll but one, Paul has been neck and neck for second place in Iowa. In most of them, he has lagged well behind the soaring speaker, coming in just below 20 percent while Gingrich hovers around 30. But a new Iowa survey, from Public Policy Polling, shows Gingrich leading Paul by just a single point, 22 percent to 21.

Moreover, the caucuses are not won by opinion polls alone. They’re won by the politician who can pack Iowa’s churches, libraries and community centers at 7 p.m. exactly on a frigid January Tuesday, and whose supporters won’t suddenly decide to back a different candidate during an hour’s worth of jawing, dealing and very public voting.

That’s how Howard Dean ended up losing Iowa by 19 points in 2004, even though last-minute polls showed him neck and neck with John Kerry and John Edwards. Dean held on to his most committed supporters, but his campaign was outhustled, outorganized and outnegotiated for the rest. His lukewarm backers either didn’t show up at all, or else they did show up and then changed their minds during the course of the caucusing itself.

Ron Paul isn’t going to take 37.6 percent of the caucus vote, as Kerry did in 2004. But he has a better organization in Iowa than Gingrich and inspires more enthusiasm than Romney, making it perfectly possible that he could eke out a narrow victory. On Monday, before the latest round of polling, Tim Carney noted in the Washington Examiner that Gingrich’s support in the state is broad but shallow (“I don’t really like Gingrich,” one Iowan told Carney. “I was just told he’s the guy to beat Mitt”), while Paul’s support is narrow but deep. If Rick Perry, Michele Bachmann or even Rick Santorum gains a little more ground at Gingrich’s expense, Paul might be able to win the caucuses with less than 25 percent of the vote.

Should Iowa really come down to Paul versus Gingrich, the clash will make for a fascinating contrast. Physically, neither man resembles a classic presidential candidate (especially compared to Romney and Perry) but for completely different reasons. Paul is all bone and sinew and nervous energy – an Ichabod Crane or a Jack Sprat, hunched and herky-jerky in too-large suits. Gingrich is broad and self-assured and faintly decadent, with a Cheshire Cat’s face and a body that looks like it’s ready for its toga.

Charlie Neibergall/Associated Press

Neither man talks like a typical presidential candidate, either: They’re more verbose, less sound bite-ridden, more digressive and less embarrassed about displaying erudition. But again, their specific rhetorical styles are worlds apart. It’s useful to imagine both of them as the kind of eccentric uncle who talks your ear off at a Christmas party. Uncle Newt has an easygoing and expansive mien, the latest gadget on his belt, and a remarkably persuasive five-point case for why you should invest in his new business venture. Uncle Ron just wants to hector you about the evils of the Trilateral Commission.

Most important, they represent two very different endpoints for the Tea Party movement. Paul, for all his crankishness, is the kind of conservative that Tea Partiers want to believe themselves to be: Deeply principled, impressively consistent, a foe of big government in nearly all its forms (the Department of Defense very much included), a man of ideas rather than of party.

Gingrich, on the other hand, is the kind of conservative that liberals believe most Tea Partiers to be – not a genuine “don’t tread on me” libertarian, but a partisan Republican whose unstinting support for George W. Bush’s deficit spending morphed into hand-wringing horror of “socialism” once a Democrat captured the Oval Office.

Paul’s rigid consistency can be a vice, and Gingrich’s flexibility a virtue. (Its disastrous ending notwithstanding, his term as speaker included genuine accomplishments that wouldn’t have been possible without a willingness to deal and compromise.) But for a movement that conceives of itself as a rebuke to the grubby compromises of Washington business-as-usual, the Texan congressman should represent a beau ideal, and the former speaker of the house should represent the enemy.

But Romney, not Gingrich, has been cast from day one as the candidate that no principled small-government conservative can possibly support. And the former speaker seems to have persuaded many people (though not me) that he could actually beat Romney for the nomination, whereas a vote for Paul is clearly just a protest vote.

So Iowa Tea Partiers face a choice. If the town hall crashers and Washington Mall marchers of 2009 settle on a Medicare Part D-supporting, Freddie Mac-advising, Nancy Pelosi-snuggling Washington insider as their not-Romney standard bearer in 2012, then every liberal who ever sneered at the Tea Party will get to say “I told you so.” If Paul wins the caucuses, on the other hand, the movement will keep its honor – but also deliver the Republican nomination gift-wrapped to Mitt Romney.