ANALYSIS: Debate Day Round II

PHOTO: Romney ObamaDavid Goldman/Eric Gay/AP Photo
Republican presidential nominee Mitt Romney and President Barack Obama speak during their first presidential debate at the University of Denver.

If it's Tuesday, it must be debate day. And talk about a change of fortunes.

Back on October 3 in Denver the question was this: Can Mitt Romney do well enough in the first debate to halt a surging President Obama?

Tune in to for livestreaming coverage of the second 2012 Presidential Town Hall Debate in Hempstead, N.Y. Coverage kicks off with ABC News' live preview show at noon, and full debate coverage begins at 8 p.m.

Even Romney backers acknowledged that if the former Massachusetts Governor had not fared well in Denver it was going to be a long, cold and frustrating five weeks.

Now it is Obama who has to find a way to stop the forward momentum that Romney has built since the Denver debate -- momentum that is showing no signs of abating.

New polling in Pennsylvania shows President Obama's double digit lead in the Keystone state is now down to four points. And Republicans are telling us that they are seeing this tightening in plenty of other states (like Pennsylvania) where Romney isn't even spending a dime.

So, what's at stake tonight at Hofstra University, the site of the second of three presidential debates? Here's The Note's rundown from ABC News Political Director Amy Walter:

• Denver gave Romney a second chance. After months of being defined by Team Obama and negative ads, voters got a very different view of the Republican nominee. As one undecided voter at a Columbus, Ohio focus group sponsored by the Annenberg Public Policy Center at the University of Pennsylvania remarked last week: "I saw a different side of Romney that I didn't know existed."

• Obama has to show voters that he actually wants a second term and that he has some specific answers for why voters should expect the next four years to look any better or different from the previous four. Simply reminding voters of how bad things were when he got to the White House isn't enough. He needs to tell voters what he's going to do to make the next four years better for them.

• These are two men who often struggle with the "empathy thing." As we saw in Denver, they know how to rattle off numbers and statistics, but neither related all those statistics to real people. Tonight, they will literally be looking those real people directly in the face.

• Aggressively Appropriate: Partisans like to see their guy throw punches (see, for example, "Biden, Joe"), but that's not what undecided and swing voters are looking for. They want to see what the candidates are going to do for them, not what they are going to say about each other. This puts a premium on being able to subtly undercut your opponent's arguments, while never losing sight of the voter who asked the question in the first place.