Romney and Obama's second meeting was a bit more contentious than their first. Unlike in the first debate, the president came ready to battle. Obviously, the left's demands that he become more aggressive and assertive were successful.
Romney started out strong, and his final remarks ended his showing tonight on a high note. Romney's remarks on the economy, college graduates, trade policies, and the current state of the middle class were often very effective.
There is an uncertainty: this was a very contentious debate, with Obama and Romney talking over each other at times. I'm not sure how this will play with undecideds. Some might view Obama as less presidential for getting into such heated exchanges, but they could also become aggravated with Romney and view him as too belligerent. Or it might not make any difference.
Romney had the momentum going into this debate. I'd guess that the president did well enough tonight for
his troops on the left to rally behind him. I'm not sure I can say
Obama won the debate, but he didn't lose it decisively, either---at least compared to two weeks ago. And Romney might still have the momentum.
UPDATE: Polling suggests, and some in the Romney campaign have been quick to emphasize, that Romney dominated on economic questions. For example, in the CBS snap poll after the debate, Romney won the economy 64-35. I've also heard that there's been some potentially positive movement for Romney among undecided women voters after this debate. More polling will show if that movement is realized over the next week or so.