Time's Michael Scherer had a nice piece Thursday about the GOP battle for third here, which could turn out to be nearly as important as the Huckabee/Romney fight for first. One interesting nugget:

His new position on the issue is a substantial shift from last year, when Thompson said in a Fox News interview that it was not realistic to expel the roughly 12 million illegal immigrants who are here. "You're going to have to, in some way, work out a deal where they can have some aspirations of citizenship," he told Hannity and Colmes in April of 2006.

But his new position--no "amnesty," crack down on employers who break the law--has had little trouble earning credibility among the state's more hard-line immigration activists. Last week, the anti-immigration movement's standard-bearer, Colorado Rep. Tom Tancredo, dropped out of the race and threw his support to Romney. But on the ground in Iowa, most of Tancredo's support appears to have shifted to Thompson, including former U.S. Senate candidate Bill Salier, who was Tancredo's state campaign director, and Angie Weaver Anderson, who ran the western end of the state for Tancredo. "I don't know anybody who was with Tancredo who went with Romney," said [U.S. Rep. Steve] King [Thompson's Iowa campaign chairman], after the last of the crowd had begun to filter out into the snow. "I have yet to find the first person."

Though Thompson seems to have fizzled in the last few days (er, above and beyond the extended fizzle that's been going on since September), it's important to note that King and Salier are both beloved by conservatives here, particularly immigration hard-liners. (Salier is a former Marine who came out of nowhere to almost defeat Rep. Greg Ganske in a GOP Senate primary a few years back.)   

On the other hand, you get the sense that McCain's New Hampshire momentum is really spilling over here. Among other things, he's now going to make a previously unplanned visit to Iowa on Wednesday and Thursday--touching down in the east, heading to Des Moines in the evening, then out west to Council Bluffs and Sioux City the following morning. Either this is one of the great head fakes of the campaign, or the McCain people really see something developing, and recent polling suggests the latter. The Pollster.com trend line has McCain surging to third in the last few days, with Thompson close to flat and Giuliani nose-diving into Ron Paul territory.

One other thing: Don't forget about McCain's Sam Brownback endorsement from a few months ago. A Brownback aide tells me that a couple of staffers and most of Brownback's volunteers went over to the McCain camp after the endorsement, and the senator himself will be here later in the week to stump for McCain. Brownback obviously doesn't command masses--otherwise he wouldn't have dropped out. But he does give McCain real cred with pro-lifers, which could be important in the final few days here.

Update: The McCain campaign tells me the Iowa trip Wednesday and Thursday has been planned for weeks. It may still be a head fake, but it doesn't sound like a response to a late-breaking development.

--Noam Scheiber