Women are the key to President Obama's lead in Ohio, and Ohio is his key to stopping Mitt Romney's momentum nationally and winning the electoral college vote. Obama is still leading Romney in Ohio, but by a smaller margin: 5 percentage points, according to a new CBS News/ Quinnipiac poll, compared to the 10-point lead the poll found September 26. Obama has lost his lead nationally in many polls because women have switched to Romney. But the CBS poll finds Obama winning Ohio women by 15 points, 55 percent to 40 percent. The gender gap could be the biggest ever this election, and if it is, it probably helps Obama. He needs Ohio women to win. 

Why it's all about Ohio: Romney has the lead in several national polls, and a big one in Gallup's tracking poll, where he was ahead 52 percent to Obama's 45 percent among likely voters Sunday. You would expect swing state polls to follow national polls -- that's why they're swing states. The Obama campaign's plan to block that. They want to stop Romney's momentum by winning Ohio, Nevada, and Wisconsin, Politico's Glenn Thrush and Jonathan Martin report. Obama has an average lead of 2.8 points in Wisconsin, 3 points in Nevada, and 2.2 points in Ohio. 

Why it's all about Ohio ladies: A Politico/ George Washington University poll of likely voters find Romney leading 49 percent to Obama's 47 percent. A week earlier, Obama led 49 percent to 48 percent. Why the change? The ladies. The survey finds Obama leading among women by 6 points, a little more than half of his 11-point lead the week earlier. If women seem to be wavering more than men, that's because undecided voters are more likely to be women. After the first presidential debate, Romney wiped out Obama's lead among women, according to a Pew Research Center poll, giving him a lead of 49 percent to 45 percent. Monday's Politico poll was taken mostly before the second presidential debate (the one Obama didn't coast through). But Obama's victory was not as clear as Romney's was in the first debate.