Sam Marcosson, law professor at University of Louisville Brandeis School of Law: "I thought Romney was ... not as effective, sort of a tick lower, a notch lower than he did in the first debate. I thought his comfort level wasn't as high, be it that the format or maybe with the president's higher level of aggression ... and it tended to produce some answers that were not effective for him. ...The difference in Romney's level of performance was not nearly as stark as the president's performance, which was night and day. I think the risk that I perceived coming in for the president is that he would mistake the lesson of Joe Biden and try to imitate Biden, and I think that would have been a mistake -- he had to be himself and yet find a way to be more aggressive, more strong an authoritative without trying to pretend he was Joe Biden. .... For Gov. Romney I think that the energy moment was good , when he was able to hammer home that point . While I think he was overly competitive, I think as a debater you always want to come back when you have the opportunity to return to your best themes to emphasize your message -- he did that. ... Tax cuts are pretty popular, but Romney so vulnerable, I think, and that vulnerability showed up tonight in the fact that he just won't give specifics on how he's going to pay for it. ... The highlight for Obama is that he was able to talk ... about positive accomplishments in the first term ... but tonight he was willing to do that. ... I think Obama on substance as well as style a little bit he was weak on energy policy. I think he was good at talking about holistic policy -- wanting to combine a lot of different things -- but he never was able to really engage the question. Like the question about gas prices, and he tried to slide around that question ... he didn't really talk about the Secretary of Energy."