That debate was a game changer. Debates don’t often matter, but it’s becoming increasingly clear that the one last Wednesday definitely did. The polls have swung wildly in Mitt Romney’s favor since then, giving Romney small leads nationwide.
If Romney wins the election now, he can have the debate to thank. It showed he had the leadership capabilities necessary to be president, and the enthusiasm and energy to get things done. Debates haven’t often mattered, but in 1960, 1976, 1980, 2000 and 2012 they have.

Romney has gotten a huge boost in the polls. In the Pew poll, which has a history of slightly overestimating the Democratic vote share, Romney got perhaps his largest bump. Pew does monthly polls, and in September Romney was down 51/43. In the poll that came out Monday, he was up 49/45.

The internals of the poll were great news for Romney too. In September’s poll, he was down among voters age 18 to 49 by a margin of 56/39, but in October was up by a margin of 49/46. That’s a total swing of 20 points.

In September he was down by 18 points among women; now he’s tied. This poll also showed him with a net favorable rating, correcting a problem that has plagued Romney since the start of his campaign.

However that wasn’t the only good news in the polls for Romney. Real Clear Politics is a site that averages out the polls in all sorts of races, and Tuesday was the first day of the general election in which the average of polls showed Romney in the lead, even if only by 0.7 percent. There are still several pre-debate polls included in that average, too. As they go away, I would expect for Romney’s lead to expand.

The debate isn’t the only thing that’s going to help Romney in the polls. Currently, many of the polls are of registered voters, not of likely voters. There is a generally accepted convention that registered voters are a subset of adults, likely voters are a subset of registered voters, and actual voters are a subset of likely voters.

Each of these subsets is a slightly more Republican population than the one before it. The kinds of people least likely to vote are also the kinds of people likely to be Democrats, on average. Minorities, younger voters and lower income voters are all relatively solid Democratic constituencies and are all groups least likely to turn out and vote.

What does this mean for polling? Combine the demographic realities with the emerging enthusiasm gap showing Republicans much more enthusiastic about voting than Democrats, and this means that when pollsters switch from registered to likely voters, their samples will get more Republican.

All of this combined should show the Obama campaign that they need a game changer much like Romney had last Wednesday. But as fewer people are expected to watch the next debate, any possibility for turn around from that alone is minimal. Add to this that the format of the debate is a town hall style (where questions are asked by audience members), which is more difficult to be aggressive in, and the race is going to get much closer in the last four weeks of the campaign.

Keene is a junior majoring in political science, economics and public policy. He can be reached for comment at [email protected]