The influx of white-collar suburbanites into northern Virginia helped Obama win the state in 2008, the first time since 1964 that a Democrat has carried Virginia. In New Hampshire, a similar suburban influx has helped break the Granite State’s Republican lock.

Colorado and Nevada could depend on turnout by Hispanic voters, who polls show prefer Obama overwhelmingly.

In Iowa, the middle class is the group to watch.

“We have low unemployment. And it’s not farms, because Obama has been good for agriculture,” said Sen. Tom Harkin, D-Iowa. “It has to do with the loss of wealth by the middle class, and that’s not unique to Iowa.”

– Slipping away from Obama? Florida and North Carolina. Privately, Obama supporters bemoan a struggling effort in Florida, though the president held a raucous rally Tuesday in Delray Beach that drew 11,000. Romney has been slowly gaining and was up 1.8 percentage points Tuesday in poll averages reported by RealClearPolitics, a nonpartisan website.

“Florida’s one of those states, it’s like a freight liner, and once it turns – and I think it’s turned – it’s hard to turn back,” Madden said.

North Carolina appears to be heading out of Obama’s reach. The campaign insists it has thousands of volunteers stumping hard, but Romney averages nearly a 6 percentage point lead in the latest polls.

– Ohio: A political world of its own, the state is always an election year puzzle and will be visited frequently by the canddiates because its diverse population largely mirrors America.

Analyst Peter Brown of the Quinnipiac University poll found that though Romney has cut Obama’s 10 percentage point lead last month in half, making up 5 more percentage points in such a short time is difficult.

– Big Obama states: Pennsylvania, Michigan, Wisconsin and Minnesota. Obama’s Pennsylvania lead in the Quinnipiac poll last week shrunk to 4 percentage points, down from 12 in September, as Romney’s favorability rating was up 5 percentage points.

Adding Rep. Paul Ryan of Wisconsin to the Republican ticket has helped put that state in play, and Romney’s Michigan roots – his father was the state’s governor and his family is still active – gives him a boost. Minnesota remains a long shot – Republicans say they’re making a renewed effort; Democrats scoff.

– Big Romney states: Arizona and Montana could swing away from Republicans, at least in part because of tight U.S. Senate races that could draw more Democrats to the polls

A Rocky Mountain Poll earlier this month in Arizona found Obama and Romney in a statistical tie. The difference, wrote research director Earl de Berge, will depend on who best turns out their voters “and whether the Democrats can hang onto the Latino vote.”