It’s just one poll, but that’s the first time he’s led in the state in nearly three weeks — and the same poll had him trailing Santorum by nine just a week ago. Another poll out today has the race tied and PPP’s new one, while showing Santorum still ahead by four, has Romney roaring back from a 15-point deficit over the past seven days. (Rasmussen also has Santorum up by four.) How’d he do it? Relentless laser bursts from the Super PAC death star taking their toll on Sweater Vest or something else happening on the ground? Dave Weigel notes that Santorum remains popular among Michigan voters despite losing 11 points to Mitt this week, so the death star’s probably not the culprit. Rather, he speculates that the recent media attention to contraception and Santorum’s outspoken criticism of it might be starting to bite: According to PPP, Michigan voters view birth control favorably by a 56/22 spread. Dig further into the crosstabs and you find this:

Santorum crushes Romney among men but trails by four among women, a gender gap between them that we’ve seen before. Just one little wrinkle in the theory, though: If contraception is hurting Santorum with women in Michigan, how come he’s surging among women nationally?

In a week when much of the national media attention on former Sen. Rick Santorum’s presidential campaign focused on his views on contraception, the Gallup tracking poll showed Santorum’s support among women increasing by 12 points, vaulting him into a 10-point lead among women over former Massachusetts Gov. Mitt Romney…

In the week of Feb. 13-19, according to Gallup’s presidential primary tracking poll of registered Republican voters and Republican-leaning independents, Santorum led Romney 34 percent to 29 percent among men and 36 percent to 26 percent among women

In Gallup’s previous week of polling–Feb. 6-12–Romney had led Santorum among men by 32 percent to 28 percent, and among women by 36 percent to 24 percent.

Not only did Santorum gain twice as many points among women last week than he did among men, he actually now does better overall among the former group than the latter. At the very least, then, the contraception issue isn’t impeding his surge in the national polls with either gender; at most, it might actually be helping him insofar as it’s drawing socially conservative women who object to the new HHS contraception mandate into his camp. In fact, in Arizona, where Romney still leads by four, there’s almost no gender gap at all. He beats Santorum by three points among men and five points among women. The problem for RS is that, even though he leads Romney by 10 points nationally in Gallup’s tracker, fully 58 percent of Republicans still think Mitt is more electable against Obama. That’s a high hurdle for Santorum to overcome with undecideds. Could be that Weigel’s right insofar as Michigan voters like RS and respect his views on contraception but have gotten increasingly worried that he simply won’t play in the general election.

According to Nate Silver’s statistical model, the state is now almost a perfectly even toss-up. Seven days and counting.