Schmidt argues that, thanks to missed opportunities at the Republican convention, Romney still faces the task of defining himself and his vision to the American people. Moreover, some analysts argue he must also use the platform as an opportunity to woo new voters - including some of Mr. Obama's - if he wants to make a play for swing states like Ohio, where some recent polls show him outside the margin of victory.
"Not only does he have to stand side by side with the president and just get through it, so to speak, he's also going to have to change some minds," said Democratic strategist Michael Feldman, who advised Al Gore in his 2000 presidential bid.
According to Feldman, it's critical that Romney present his own policy ideas while effectively challenging the president's record - all without sacrificing his gravitas. Given his past struggles relating to everyday Americans, that's something he isn't sure will come easily to the candidate.
"He hasn't quite connected to voters yet on a variety of levels," Feldman said. "And it's hard when you're delivering a hard hit on your opponent to come across as being likeable at the same time. But that's what he has to do."
"The problem Romney has is, you never want the words 'make-or-break' associated with your name. So here he is under so much pressure from the media and his supporters and his donors to really deliver something, and yet it's really hard to do that," said Alan Schroeder, a professor at Northeastern University and the author of "Presidential Debates: 50 Years of High-Risk TV." "He has expectations that are in some ways lower, because he's the underdog, but in some ways they're higher - because there's so much pressure on him to succeed."
Romney, of course, is not alone in facing challenges. The president's backers have noted repeatedly that his rhetorical style doesn't mesh with the traditional debate format, and efforts to lower expectations on his behalf went unrewarded: According to a recent Pew Research study, a majority of voters - 51 percent - think the president will win the debate, while only 29 percent said the same of Romney.
To boot, debate moderator Jim Lehrer is also playing with a looser format -- which may not be the ideal set-up for a president known for speaking in long, complex sentences.
"The fact is, the president is a smart guy and his rhetorical style is that he likes to explain things," said Feldman. "If his challenge is to be brief then maybe some structure is helpful for that."
"The double-edge of the expectations sword for President Obama right now is that people are expecting him to do better ... which makes his job tougher," Feldman said. A function of those expectations, he says, is that the bar is higher for the president than it is for his rival.
When it comes to preparedness, however, Romney is expected to have the edge.
"Romney's strengths are experience and preparedness. He has spent a lot of time preparing for these debates, by all accounts, over the course of the summer. And he's had a lot of experience over the last four years participating in these debates," said Schmidt. "When you watch the arc of his progress - from 2008 to 2012 - it's clear he has the capacity for improvement and he gets better. Obama simply hasn't participated in the number of debates that Romney has, and he hasn't, by all accounts, spent the time preparing that Mitt Romney has."
Nevertheless, Simmons argues that despite expectations and his proclivity for long-winded answers, the president's biggest responsibility tonight is "to not drop the ball in any significant way."
"A tie is perfectly fine for the president," he said. "The pressure is clearly on Governor Romney to change the dynamic. The president needs to do no harm."
At this point, there's only so much either candidate can do to prepare. But according to Simmons, there are a few last-minute nuggets of advice that apply to all debaters - Republican or Democrat.
"Wear good makeup. Don't sigh. Don't look at your watch," he said. "Those things are probably point number one."