Mitt Romney has surged to a 4-percentage-point lead in 12 crucial swing states, largely because he has erased President Obama's lead among women voters, according to a USA Today/Gallup poll released Monday.

The battle for women has been a major focus of both campaigns, and is expected to figure prominently in their closing arguments in Tuesday night's debate and in TV ads during the last three weeks before election day.

As a group, women tend to wait longer than men to choose their candidates, which makes them — especially blue-collar "waitress moms" hit hard by the economy's troubles — a key swing vote. Women overwhelmingly backed Obama throughout the campaign, so why are they suddenly warming to Romney? Here, five theories:

1. Romney showed them he's not crazy
Romney's "humor and authority" in the first presidential debate changed everything, says Tim Stanley at Britain's Telegraph. His pledge to protect Social Security, Medicare, and financial regulation reassured them "that while he is a traditional Republican, he isn't crazy." Romney reinforced that image after stepping off the stage, by saying he has no plans to pursue federal anti-abortion legislation, making it harder for Obama to "portray Romney as an antediluvian conservative who would swap sex-ed classes for chastity belts." Obama might be able to change all that, says Digby at Hullabaloo, if he points out that the real Mitt is all about "destroying Medicare, Medicaid, and calling half the country a bunch of dependent losers he doesn't have to care about."

2. He's blurring where he stands on abortion
"Romney has been blurry on abortion," says Margaret Talbot at The New Yorker. He promised to "preserve and protect a woman's right to chose" when he was running for governor of Massachusetts, then vetoed a bill making emergency contraception more accessible. In this year's GOP primaries, he "declared himself proudly pro-life;" now he insists anti-abortion legislation isn't on his agenda. The truth is that women's issues are among "the starkest differences between the Obama and Romney tickets." Romney's GOP doesn't just want to limit "the right to abortion but, astonishingly, the right to contraception, too." Women can't "pursue education and careers" if you deny them the right to "plan when they will give birth." Romney's hoping they won't notice what he's up to until it's too late.

3. Women are worried about the deficit
Abortion isn't "the losing issue for the GOP" many Democrats think it is, says Laura Vanderkam at USA Today. They're as likely to favor abortion rights as they are to oppose them, and "more women will pay into the Social Security system, for instance, and will send their children to schools, than will ever have an abortion." Besides, we've had Republican presidents and Congresses, and they haven't overturned Roe v. Wade, "so it seems unlikely the next president will be able to institute an immediate nationwide abortion ban, let alone a ban on birth control." The reality this campaign season is that voters, women included, "rank jobs, the economy, and the federal budget deficit as more important than abortion." 

4. Romney showed he's a good listener
Republicans, citing internal polls, think they know how Romney won over women, says Mike Allen at Politico: Their focus groups, one GOP insider says, told them that women who watched the first debate found Obama to be "the interesting but arrogant guy that turns them off." Romney "was a reliable father. He showed women that he's a listener." In the first debate, the Republican source said, Obama "was the husband who says: 'That's your problem? Here's the solution.' Mitt was the husband who says: 'Well, you, know I've been thinking about this. I've got some ideas. You wanna talk about them?' Women want to know that you listen to them." Both candidates, Allen says, will try to come cross as "the good husband" in Tuesday's debate.

5. The poll is wrong
The "GOP poll denialists" really were "crazed" when they insisted that pollsters were deliberately skewing their surveys to give Obama an edge, says Jonathan Chait at New York. The Obama campaign, however, is right when it says the USA Today/Gallup poll is malarkey. Poll denialists said pollsters were simply interviewing too many Democrats. Team Obama is saying that Gallup, which found that registered voters prefer Obama by 4 points, is messing up when it calculates who's actually going to show up and cast a ballot on election day. Gallup is giving the GOP a 9-percentage-point edge among so-called likely voters. "Historically, Republicans vote at a higher rate than Democrats. But the difference is usually a couple percentage points, not 9."