Ever since Mitt Romney’s initial surge in polls in the wake of his dominant Oct. 3 debate performance, the race has settled down into one in which Romney enjoys the edge in most national polls, while state polls suggest President Obama has the edge in Ohio. No recent poll has shown Romney leading in Ohio, and though not impossible, it will be difficult for him to win the presidency without the state.

Right now, it isn’t clear where the race is in Ohio. According to the Real Clear Politics average of polls, Obama has an edge of 2.3 points. But the average may not be a reliable gauge as to where things stand, because as Jay Cost has diagrammed, the polls aren’t clustered around that average, but instead, they are scattered all over the place. Of the 11 polls used in the average, three of them have the race tied, while another three have Obama up at least four points.

In 2004, the Ohio exit polls found that of the 11 percent of voters who decided in the last week of the campaign, John Kerry won 60 percent to 40 percent. That suggests that in the last week, Kerry closed the gap by about 2.2 points. In 2004, obviously President Bush had enough of a lead that Kerry’s gains turned out to be too little, too late. If there’s a similar number of late deciders breaking toward Romney as they did the challenger in 2004, then it could potentially be enough to put him over the top. It just depends which polls are closer to the truth. If Obama is in fact winning Ohio by four or five points, then it’s very unlikely to see how Romney closes the gap over the next week and a half. If, however, the race is tied there, or Obama has a very narrow edge, then it’s possible that a similar break to the one Kerry had would be enough for Romney to take the Buckeye state, and likely, the presidency.