White Male Vote Especially Critical

"We want to campaign closer to the ground than we did in those two weeks, where we did a lot of rallies, and they have their place," he said. "But there are all kinds of other things we'd like to do and should do that connotes the fact, which is that he is a bottom-up, grass-roots person who has always been about -- from the time he was an organizer in the shadow of closed steel mills, who has been fighting and working for people who were squeezed."

James P. Hoffa, general president of the International Brotherhood of Teamsters, said Obama should do better with working-class men in Pennsylvania. "One of the problems with Ohio was there really wasn't the time," he said. "There's going to be more time to campaign in Pennsylvania. I'm not using it as an excuse, but he didn't have the time to spend the time in the state."

The other question for Obama is whether he would have any less trouble winning the votes of working-class white men in a general election. Republican strategists look at such places as southern Ohio and question whether Obama could ever carry downscale white voters in the fall. But Stern said the difference between running against Clinton in the primary and Sen. John McCain (R-Ariz.) in the general election is significant.

"In the primary, there's another candidate who has a legitimate case to be made about caring about people who work, about standing up as it relates to special interests," he said. "But I think John McCain has a very different record here."

Axelrod argued that, given time, Obama can win over white working-class men. "I think there's still plenty of receptivity out there," he said. "I think as people get to know him, just as has been true elsewhere, we can reduce that number."

Polling director Jon Cohen and polling analyst Jennifer Agiesta contributed to this report.