(MSNBC) -- Voters will have their chance to size up President Barack Obama and Republican presidential nominee Mitt Romney side-by-side, when both men take the stage at the University of Denver Wednesday night for their first of three debates.
And with Election Day just a month away, expectations and anticipation for tonight's showdown are mile high.
Romney, the Republican presidential hopeful, trails Obama in most polls, both nationally and in key battleground states. Tonight's debate offers the challenger an opportunity to change the dynamics of the race and Romney is expected to take an aggressive posture in hopes of doing just that.
Both candidates have spent a lot of time in the critical swing state fighting for those nine electoral votes but recent polling has President Barack Obama in the lead. Gov. John Hickenlooper, D-Colo., discusses.
For his part, Obama will have to guard against his Republican opponent's attacks – particularly on the anemic economy, and the administration's response to a terrorist attack against a U.S. embassy last month in Libya – all while trying to illustrate the "contrast" between himself and Romney.
The stakes on Wednesday evening are especially high for Romney, who's trailed Obama in most polls since each party's national conventions concluded at the beginning of September. A series of missteps by the former Massachusetts governor – involving his quick response to the Libya incident and the revelation of secretly recorded remarks seeming to write off 47 percent of voters, whom he called "dependent" upon government – have put the private equity titan in the unenviable position of having to make up ground versus Obama.
October's three debates might be Romney's last, best hope to accomplish that goal. Political observers typically look toward three moments in an election for a candidate to change the state of the campaign. The first two – choosing a running mate and the national convention – have come and gone.
That leaves the debates – Wednesday in Denver, Oct. 11 in Hempstead, N.Y. and Oct. 22 in Boca Raton, Fla. – for Romney to make his argument.
The Republican nominee will look to deliver the kind of aggressive attacks on Obama for which his conservative supporters have clamored.
Several Romney voters at events here in Colorado preceding Wednesday's showdown said they feared he currently trailed Obama. All of them said they wanted to see the GOP nominee come out swinging versus the president.
"I don't think he has been tough enough," said Caroline Peale, who attended Ann Romney's event on Tuesday afternoon in Littleton. "He has so much ammunition. He doesn't use it!"
Peggy Fulster, a self-described independent voter who decided for Romney in recent months, said: "I believe he's behind, but I think he can make up ground. I think a lot of people are sitting on the sidelines to see what happens in the debates."
The risk for Romney could involve seeming too aggressive; he must straddle a delicate dividing line between criticizing the president and seeming petulant in a way that could turn off many swing voters.
Obama is sure to play defense at moments of the debate, which will be moderated by Jim Lehrer of PBS. But the debate format is largely open-ended in a way that could maximize interactions between the candidates. As a result of a coin toss, Obama will deliver the first opening statement and Romney will give the final remarks of the evening.
The president's campaign has sought to play down expectations for Obama, emphasizing that the president hasn't debated since the 2008 general election. Obama spent much of the past weekend and the first half of this week practicing for tonight's matchup, huddling in Henderson, Nev., with senior staff and Massachusetts Sen. John Kerry, the 2004 Democratic presidential nominee who is playing the role of Romney in mock debates.
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Obama, speaking a few days ago in Las Vegas, framed the debate as an opportunity to engage with Romney on issues of substance, playing down expectations and dismissing the notion of debate winners and losers.
"Gov. Romney, he's a good debater. I'm just OK," the president said. "But what I'm most concerned about is having a serious discussion about what we need to do to keep the country growing and restore security for hardworking Americans. That's what people are going to be listening for. That's the debate that you deserve."
Much of Obama's campaign has focused on illustrating the differences between the two men, rather than embracing the model of an election that is effectively an up-or-down referendum on the president's first term. Obama is likely this evening to continue in that vein, and has ample ammunition of his own to go after Romney. The Democrat's campaign has turned Romney's "47 percent" video into the subject of attack lines, and the president invokes Romney's own low effective tax rate as evidence for why taxes should be reformed such that the wealthy pay a higher share of taxes.
Like Obama, Romney has spent a considerable amount of time preparing for these attacks and downplaying expectations. Romney's team has pointed out that, despite the numerous primary debates earlier this cycle, the Republican presidential nominee hasn't faced a Democratic opponent in about a decade, when he first ran for governor of Massachusetts.
"There's going to be all the scoring of winning and losing, and you know, in my view, it's not so much winning and losing or even the people themselves," Romney said at a rally Monday evening in the Denver area.
NBC's Mark Murray breaks down the newest national and state polling ahead of tonight's debate.
Romney added: "I look forward to these debates. I'm delighted that we're going to have three debates. It'll be a conversation with the American people that will span almost an entire month."
Ohio Sen. Rob Portman, a veteran of debate preparations for past Republican nominees, has taken the lead on playing Obama in practice sessions versus Romney. Portman traveled with Romney to Denver, and the two of them mostly worked privately on Tuesday in anticipation of tonight's debate.
Would-be first lady Ann Romney pronounced her husband "excited" and "focused" in a rally Tuesday afternoon.
But whether there are that many undecided voters remaining on the sideline is another question. The challenge – for both candidates – could end up involving the number of voters who appear to have already determined their vote, making it more difficult than usual for either Romney or Obama to sway voters with a strong debate performance.
Tuesday's NBC News-Wall Street Journal poll found that most voters, 60 percent, called the debate either "just somewhat important" or "not at all important."