(CNN) -- It is widely agreed that Wednesday night's presidential debate is crucial for Mitt Romney: This is almost assuredly his last chance to turn around the election. What is less obvious is that the stakes are sky-high for Barack Obama, too: This debate could have a powerful impact upon his ability to govern in a second term. Romney is dangerously close to blowing a campaign that many election models said he should easily win. Yes, three national polls published Monday -- including CNN -- showed the two candidates within three points of each other. But for Romney, the problem is that as the polls go up and down each week, there is one constant: As Real Clear Politics demonstrates in its averaging process, Obama stays ahead and has been for nearly a year. The news for the GOP from battleground states is even worse, especially in the Midwest.
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David Gergen: Debate may represent Romney's last big chance to turn around the race
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He says the stakes are also sky-high for Obama, even if he wins election
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Obama needs a big victory to claim broad support for his plans for second term, Gergen says
Mitt Romney
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Unless he wants to depend on a wing and a prayer, @placeholder is thus in the unenviable position that he has to shake up the dynamics of the race on Wednesday night.
Barack Obama
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Obama
But his campaign has left him with so much ground to make up that it will be very hard: In the space of 90 minutes, he has to convince voters for the first time that he has a better plan for the economy, make the case that @placeholder doesn't and prove much more likable than ever before.
Mitt Romney
Romney
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And all the while, he will have to fend off jabs from Obama, who can draw from a rich trove of @placeholder mistakes in the past.
Mitt Romney
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So, yes, @placeholder can still win, but it will be darn hard.
Barack Obama
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Add together the possibility of a convincing mandate with congressional results that may be far better than expected a few months ago and what do you have: bingo, a resurgent @placeholder heading toward a second term.