(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
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.