(CNN) -- What a difference two debates have made. Before the first presidential debate last week, President Barack Obama appeared to be cruising toward re-election and possibly a thumping victory. After the first presidential debate, that changed dramatically: Suddenly, we had a horse race. Now after the vice presidential debate Thursday night, we not only have a horse race, but partisans fired up on both sides. Joe Biden relit the fire under Democrats in a passionate, often dominant tangle with Paul Ryan. Going into that encounter, Democratic spirits were not only drooping but some were beginning to panic that they were throwing away the election.
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David Gergen: Two debates in two weeks have transformed presidential race
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Gergen says the polls have tightened, partisans on both sides are fired up
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CNN poll gave a slight edge to Paul Ryan; Gergen says he had edge on style
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Gergen: Tuesday's town hall debate looks increasingly important
An old pro, @placeholder knows how to play to seniors, women and the middle class.
The CNN poll of registered voters who had watched the debate reached a similar conclusion: Forty-eight percent said @placeholder won, 44% said Biden, though the difference was within the poll's margin of error.