The best-case scenario for Mitt Romney is that his debate performance convinced some independents to vote for him and maybe even swung a Democratic voter or two.  CNN polled Romney’s debate victory at historic levels. CNN’s poll also showed a change in voter preference towards Romney across every issue. Given the near unanimity by which viewers favored Romney’s performance, it is very possible that Romney may receive a convention-like bounce.

Under the worst-case scenario, Romney does not pick up any swing voters. However, even without picking up swing voters, Romney still succeeded in inspiring Republicans. Surveying social media, talk radio, conservative blogs, and just talking to Republicans in general, the GOP excitement is at a campaign high. This is how it was supposed to feel after the convention. The excitement will lead to increased donations, full phone banks, and many more sets of legs canvassing neighborhoods. As evidence of this, former Howard Dean’s campaign manager, Joe Trippi, noted that Republican online voter registrations have been coming in at double their average rate since 20 minutes into the debate. Pollsters should certainly see a surge from a much more animated, involved base even if swing voters remain on the fence.

While history seldom remembers losers who made a comeback, but still lost, it is worth looking at John Kerry’s 2004 campaign. Kerry trailed Bush by nearly six points in September before the first debate changed the trajectory of the race. Kerry would make up more than three points in October and come within a few thousand votes of achieving an Electoral College victory.

Romney’s poll deficit is not as severe as Kerry’s was in 2004. Romney trails by about three points nationally. Before the debate, he trailed in swing states, by less than four points  in Florida, Virginia, Iowa, and Colorado. Ohio, Nevada, and New Hampshire are all within about five points. A debate bounce could equalize these small but steady leads and transform the battleground states into true toss-ups.

The first debate is supposed to be a good night for the challenger. Romney only needed to acquit himself respectably and he would have seen a small move in the polls.  Romney far exceeded expectations. The question for Romney is whether he will come up just short, despite one of the great Republican debate performances, or if he will maintain his momentum throughout the next month and be one of rare challengers to defeat a sitting President.