If this was a debate based on points and who had the most zingers then it was Obama hands down. But in the overall picture Obama failed to do what was necessary in the eyes of voters and Romney succeeded.
ROOMNEY:
Romney's job in the debate was simply to appear presidential and that he had the competence to be commander in chief. Romney did not have any big flubs, missteps, or major statements that were seen as gaffes. He did what he needed to do and showed that he was up to the task. Romney focused on big picture stuff and didn't get into the weeds much on specifics. There were opportunities that he could have went full force at Obama on the Benghazi attack mess in Libya but he held back. He could have went after Obama on a number of issues in an "attack dog" type manner, but he didn't. In the eyes of undecided voters Romney made himself look presidential. Also Romney went back to economic issues a number of times. In those moments he scored points, because most people knows that the economy is #1 issue this time around.
OBAMA:
As far as Obama he failed to get Romney into any big pitfalls. Anyone who knows about these debates realizes that one key thing a debate person can do is prepare pitfalls for your opponent to fall into. I'm sure Obama had well planned comebacks that he rehearsed regarding Libya, and other foreign policy issues. The thing is Romney ended up agreeing with Obama on a lot of things. In the debate you can tell Obama was a bit frustrated by that and some of Romney's answers. The problem is Obama didn't cause Romney to have any big mess ups. That is what he needed if he was hoping to change the momentum in this race. That did not happen.
Instead he took some swipes at Romney. A couple of those include the comment that he said while he was working on sanctions with Iran that Romney was investing in China. That is one of those low blow petty attacks that only fire up your base. The other one was when he quipped Romney about having fewer bayonets and horses and that we have things called aircraft carriers that planes land on. That statement got a lot of laughs and cheers from his base, but I assure you that not many undecided voters saw that and said, "wow...yeah Romney is a complete dumbass! I'm voting for Obama!" No, that was a petty swipe at Romney's intelligence and it doesn't work on a national stage in a televised debate as much as some in this forum are thinking it did. There were also more factual errors Obama made than Romney made. A couple of the big ones were regarding the Auto Bailouts when Romney argued for a managed bankruptcy and including guarantees. The other was on the troop withdrawal negotiations in Iraq.
CONCLUSION:
Simply put this debate did not change the race like the first debate did. In the first debate Obama barely showed up and in fact Romney caused the Obama campaign to lose all the ground they had made spending millions in attack ads on him. This debate only showed that Romney is a capable commander in chief even if Obama won the debate on points and aggressiveness. The problem for Obama is that Romney mainly kept himself from major pitfalls and made himself look presidential. Obama while had some great zingers on Romney showed himself a bit less presidential in the minds of serious undecideds. Obama did draw some blood on Romney, but it was not enough to change the momentum. There was even a CNN left leaning commentator after the debate that said that Obama won the debate but Romney came away looking presidential.