Great debate Tuesday. Both candidates had their moments, but when the dust settled, Romney's most memorable moments were negative ("binders full of women" and the Libya thing) whereas Obama's were positive (the Libya thing and calling Romney on his bullshit).
After the first debate, deeper polling showed that its main effect was an increase in Republican enthusiasm for Romney and a drop in Democratic enthusiasm for Obama. That produced a post-debate bounce for Romney (but not enough to completely erase the lead Obama had going in). As data came in the weekend following the 1st debate, it started to look like Romney's bounce was leveling off.
Then we had the VP debate where Biden mopped the floor with Ryan and helped recover some of the Democratic enthusiasm that was lost the week before. Polls with data after that debate showed that effect, with Obama starting to separate from Romney.
IMO, Tuesday's debate will further that trend. Obama came out strong and assertive, and didn't let stand Romney's promises that everyone could eat all the sweets they wanted and never gain a pound. He also reminded Americans of the "severely conservative" Romney who ran in the Republican primaries. before the etch-a-sketch was shaken and a different Romney emerged.
Nate Silver at FiveThirtyEight is showing that the Romney bounce is over and Obama is maintaining a lead in key states, albeit by slim margins.
http://fivethirtyeight.blogs.nytimes.com/
With another debate on Monday and the election in less than 3 weeks, Romney needs to do something to regain the momentum he had after the first debate. OTOH, if Obama can follow up with another strong performance on Monday, and no "surprise" emerges between now and election day, it looks like he'll win another 4 years. Also, it looks like the senate will remain in Democratic control and the House in Republican control. What'll be interesting is if Congressional Republicans actually start to work with Obama rather than opposing everything in hopes of winning the White House.