Another poll out, this one from Rasmussen Reports, suggesting a last-minute Rick Santorum surge in Iowa.

Santorum has an Iowa ad that plays up his anti-abortion voting record. It notes that he’s been married for 21 years and has a whole bunch of kids and that they’ve all been home-schooled. It features praise from Mike Huckabee, too and was apparently inspired by VH-1′s pop-up videos.

I’ve been pouring over polling data, and I’ve reached a few conclusions:

1.) If Mitt Romney wins the Iowa caucuses, Mitt Romney will be nearly unstoppable in the 2012 Republican primaries.

2.) If Ron Paul wins the Iowa caucuses and Mitt Romney finishes second, Mitt Romney will be virtually unstoppable in the 2012 Republican primaries. [A Paul victory will scare the living daylights out of establishment Republican leaders and they'll circle the wagons. Plus, it will suck up all the media attention, leaving little benefit for whoever finishes third...]

But if an Anti-Romney (other than Ron Paul) finishes first in Iowa, things are going to get mighty interesting and incredibly unpredictable awfully fast.

So far, several would-be Anti-Romneys have risen to the front of the pack, including Bachmann, Perry, Cain and Gingrich.

But each of them withered once the media spotlight focuses on them. Now, the Iowa caucuses are less than a week away and polls suggest the race remains fluid.

Evangelicals make up about half of the Iowa Republican caucus base, and they’re really skeptical of Mitt Romney, if you believe a plethora of polls out there.

Gingrich is fading, and his polling trend lines suggest his descent will continue. Perry is stagnant. In Iowa, folks who like Michele Bachmann disproportionately like Rick Santorum. And vice versa. Both are polling in low double digits in the latest poll, by Public Policy Polling.

Both are faring well among Iowans who voted for Mike Huckabee in 2008.

If Bachmann and Santorum draw equal numbers of voters on Caucus day, it probably guarantees that Mitt Romney and Ron Paul will cross the Iowa finish line in first or second place.

But if either Bachmann or Santorum begins to falter in the final days, we could see a stampede toward whichever of the two looks strongest.

And if that shift becomes clear in the final days, it’s likely that many Perry and Gingrich-backers will be tempted to jump on the bandwagon.

Now, a new poll released today suggests it is Santorum is peaking at the right time. It suggests Santorum has pulled ahead of Bachmann and is nearing the front of the pack.

If he’s seen as the ascendant Anti-Romney on caucus day, he could pull off a real stunning come-from-behind victory.

Polling suggest that Santorum — despite polling poorly until recently — has high overall favorability ratings amond Iowa Republicans. Nobody has slung mud at him until now because nobody thought he had a chance. And now, if he is gaining momentum, it may be too late to try to effectively trash him.

Plus, Santorum has basically been living in Iowa. And he’s spent time in all 99 counties. He’s done the leg work and his ground game is better in Iowa is better than many of his opponents. In addition, he’s a loyal, churchgoing Catholic. His appeal can stretch beyond the 2008 Huckabee electorate.

If Romney wins in Iowa AND wins in New Hampshire, it’s hard to come up with a blueprint for stopping him. However, if Santorum rallies evangelicals in Iowa, he can fight through New Hampshire and head to South Carolina, where he’d be the early odds-on favorite.

Any candidate who trails Santorum in Iowa (other than Mitt Romney) will immediately see their fundraising efforts run aground, and the field will immediately narrow.

Mitt Romney will remain a formidable candidate, no matter what happens in Iowa. He has more money, better organization, high name recognition and impressive discipline. He’s been thoroughly vetted and he’s spent the past five years honing his presidential campaign skills.

Once the media spotlight shines brightly on Santorum, he’ll face the tough kind of scrutiny that follows a frontrunner. And he could crash and burn, leaving the race to Mitt Romney by default.

But there won’t be time to fire up that spotlight until AFTER the Iowa caucuses.

Pop quiz for campaign buffs.

A rich Republican politician with disputed conservative credentials and New England ties who had distanced himself from Ronald Reagan in the somewhat distant past tries to present himself as the heir to the Reagan Revolution.

Iowa Republican voters groan and guffaw and reject the well-funded putative frontrunner. He loses badly — even a Southern Baptist preacher tops him in the caucuses.

A few days later, New Hampshire Republican primary voters: (Pick all that apply)

A.) Deliver a second-consecutive defeat to their New England neighbor and his campaign never recovers.

B.) Embrace their New England neighbor and he goes on to win the presidency.

C.) Neither A nor B.

D.) Both A and B.

Answer below the jump. (more…)