Romney has steadily gained in the Gallup poll in recent weeks, turning what had been a growing deficit in September into a growing lead since his strong first debate performance. And when Gallup shifted its voter model from registered voters to likely voters last week, Romney's numbers improved even more (among registered voters, the race is at Romney 48, Obama 46).
The new numbers, of course, don't include much or any data collected after Tuesday night's debate. It will take days to determine what effect that might have had.
In addition, Democrats have cast doubt on Gallup's likely-voter model, with the Obama campaign releasing an entire memo on it earlier this week when Gallup showed Romney opening up a similar lead in the 12 most competitive states in the country.