The number of white Democratic voters who said that race influenced their choice on Tuesday was among the highest recorded in voter surveys in the Clinton-Obama nomination fight. Two in 10 white West Virginia voters said that race was an important factor in their vote, and more than 8 in 10 of them backed Mrs. Clinton, according to surveys of voters leaving the polls.

With Mr. Obama still solidly ahead of Mrs. Clinton in the delegate fight, the West Virginia results are unlikely to adversely affect Mr. Obama’s chances of winning the nomination. Yet a strong Clinton victory in another general election battleground state  like her wins in Ohio and Pennsylvania this spring  could raise fresh questions about Mr. Obama’s ability to carry swing states in a contest against Senator John McCain in the fall.

Image Senator Hillary Rodham Clinton with her campaign chairman, Terry McAuliffe, in Charleston, W.Va. Credit... Chris Keane/Reuters

The voter surveys showing a strong racial component to the West Virginia voting suggest that Mr. Obama would still face pockets of significant Democratic resistance if he does become the party’s first black nominee. While he has argued that he could broaden the Democratic base in the fall, given his popularity with independents and his strong showing in traditionally Republican states like Colorado and Virginia, the Clinton camp has pointed to his modest support from white voters and blue-collar workers as weak links in his coalition.

Obama supporters accused Mrs. Clinton of playing the race card last week when she explicitly said that she had more support among “white Americans” than he did. Yet however blunt she may have been, white and financially struggling voters in West Virginia  and in Kentucky, which votes next week and which Mr. Obama has all but conceded to Mrs. Clinton  have become a major force keeping her in the presidential race at this late stage.