From Hempstead, New York -

The next twist and turn in the race for the White House could well depend on what happens in the second Presidential debate between President Obama and Republican Mitt Romney, as they face off at Hofstra University in New York on Tuesday night.

"Governor Romney wants to capitalize on what he did in Denver and President Obama has to kind of recover from that," said Meena Bose, a presidential scholar at Hofstra.

"It's a challenge for both President Obama and Governor Romney," Bose told me in the media filing center set up for the debate, as she rightly noted the up and down performances by both candidates in past debates.

The format also presents its own challenges, as the questions will mainly be asked by undecided voters from the New York area, who will pose their queries in a town hall format, all on the same stage as Messrs. Obama and Romney.

"I think it's harder for the candidates to attack each other," Bose said, saying that with voters just a few feet away, the idea of slashing attacks might not play that well.

One would expect that the President will try to bounce back from his lackluster debate earlier this month in Denver; since then, the polls have definitely shifted towards Romney and the Republicans in swing states - and another performance like that could be a death blow with just three weeks left until Election Day.

The wild card obviously is what will the voters ask about?

One can assume that we will plow familiar ground on the economy and more; whether we get into foreign affairs is not as clear - that will be the sole focus of the final debate next Monday October 22.

While both sides will certainly be able to figure out most of the attack lines that the other will focus on, like the "47% remark" of Romney and the issue of whether you are better off than four years ago, it is important to realize that maybe substance really didn't play a huge role in the first debate.

Yes, Romney was judged to be the winner of that debate - by voters in both parties and independents.

But was it because his arguments were better or that he had the high ground on a number of subjects? I'm not so sure about that - to me, it was all about the bad performance of the President, and how he did not look like he really wanted to be there.

"I think image matters," Bose told me. "You want to convey that you are happy to be here."

For Bose, the important goal for both candidates is to try to connect with the undecided voters on stage.

So far we have had two debates where the President and Vice President have drawn a lot of scrutiny for what they were doing when they were not speaking; we'll see if that gets repeated tonight.

The President would probably be happy with a more assertive night where he gets into the meat of the issues and goes on the offensive a little.

Romney would likely be pleased with a debate that - as a minimum - was seen as a draw, so he can keep his momentum going.  Another debate "win" would be huge for his campaign.

The polls definitately moved after the Denver debate - will they do so again after this one?