At the heart of the matter is the gender gap. Men and women have diverged in every presidential race since 1980. In 2008, Mr. Obama won 56 percent of the female vote (versus 43 percent for John McCain) and 49 percent of the male vote (to Senator McCain's 48 percent), for a seven-point gender gap. For now, Obama leads Mr. Romney among women in major polls – by 20 points in the latest Pew Research Center poll, fewer in others – and is tied or trailing Romney among men.
The likely question for Obama, then, isn't whether he will get more women than men to vote for him, but how big the margin will be. If Obama is to win, he will need a big women's vote to offset an expected deficit in the men's vote.
"The reason the gender gap is so important is not just the difference in points between men and women, it's that there are more women than men overall, more women registered to vote, and a higher female turnout rate," says Dianne Bystrom, director of the Carrie Chapman Catt Center for Women and Politics at Iowa State University in Ames.
Republicans say the blowup over birth control won't harm the party's chances in November.
"I'm not making light of the fact that there was a hit to the party, but the collective damage was probably short term," says Linda DiVall, a Republican pollster. "Do I expect it to be a lingering problem that will hurt us in the fall? No, I don't. The focus will still be on the economy."