Mr. Kimbrough is an Obama supporter but he would not hazard a guess as to how his white buddies will vote. He said economic disaster had exacerbated racial tensions. With the mills closed, the work force is resegregating.

Carl Davidson, a white friend and an Obama supporter, sat in Mr. Kimbrough’s living room. “My father voted for Edwards in the primary and now he wants McCain,” said Mr. Davidson, whose father and grandfather labored in the mills. “Without realizing it, he’s wrapped up in white-identity politics.”

Sorting out white-voter discomfort with Mr. Obama is tricky business. Most speak of unease with his newness. But one in five primary voters surveyed in the Edison/Mitofsky exit poll in Pennsylvania said race was a factor.

Ivan Stickles, a carpenter, worked on his motorcycle in his driveway in Hopewell. Mr. Stickles, 57, is not taking what he sees as a gamble on Obama.

“There’s this e-mail that he didn’t shake hands with the troops,” Mr. Stickles said of a rumor that is false. “I don’t have the time to check out if it’s true, but if it is, it’s very offensive.”

In Hookstown, Kristine Lakovich, 48, works the counter at Kiner’s Superette. She likes Mr. Obama, a preference she keeps to herself. “If you ask people around here, he’s not exactly the right answer,” Ms. Lakovich said. “People are split between their politics and their prejudice.”

Nationally, the Obama campaign shies from talk of race, preferring to argue that the poor economy will dominate this election. Such delicacy holds no purchase here. An organizer with the United Steelworkers met with 30 workers in Beaver. He could not have been blunter. Mr. Obama, he told them, stands for national health care, strong unions and preserving Social Security.

“Some of you won’t vote for him because he’s black,” the organizer concluded. “Well, he’s a Democrat. Get over it.”