WASHINGTON -- Leon Panetta says the Democrats face "several land mines" in this presidential election, one of them being "this racial division between African-Americans and white voters."

"If that continues, there is no way the Democrats can win in November," Bill Clinton's former White House chief of staff told me.

It is an ominous warning delivered by one of the party's most respected political advisers who has been a Hillary Clinton supporter since day one.

The problem is a sensitive one among Democrats, but Clinton and her supporters, bloggers and now one of the party's elder statesmen are raising the issue.

Hillary Clinton's remark last week about "white Americans" came up Sunday on "Meet the Press" in a question Tim Russert put to Clinton fund-raiser Terry McAuliffe. The New York senator had pointed to an Associated Press poll that, she said, "found how Sen. Obama's support among working, hardworking Americans, white Americans, is weakening again, and how whites in both states who had not completed college were supporting me."

Harlem Rep. Charles Rangel, one of Clinton's original supporters, told the New York Daily News, "I can't believe Sen. Clinton would say anything that dumb." New York Times columnist Bob Herbert charged that she was in effect raising the race issue to boost her support in the West Virginia primary.

The Daily Kos Web site, the bible of the Democratic left, ran a lengthy analysis Monday entitled "White Voters, Obama and Appalachia." It asked why the Democratic front-runner was running poorly in states like Kentucky and West Virginia and in the rest of Appalachia, which stretches from New York into the Deep South.

The analysis, replete with demographic-vote maps of the region, said it does not believe Obama "has a significant 'race problem,'" but "he has and will continue to have a problem with some white voters who are clustered mostly in Appalachia."

After all, among the nearly 30 primaries that Obama has won, many were in states where there are relatively few black voters, like Iowa, Idaho, Utah, Vermont, North Dakota, Wisconsin, Wyoming, Washington, etc.

Still, there were clear signals in recent polling data that raise questions about Obama's drawing power in key swing states that Democrats must carry if they are to win in November.

A Quinnipiac poll released May 1 showed Clinton leading John McCain in Florida, Ohio and Pennsylvania, but Obama merely ties McCain in Ohio and Florida, though beats him handily in Pennsylvania.

Yet Panetta, who remains personally close to the Clintons, is under no illusions that the former first lady has much of a chance in the final rounds before primary season ends in June.

"Unless something unforeseen takes place between now and June, you clearly have to say Barack Obama is in a very strong position to get the nomination," he said.

"But I understand that having come this far, having fought the battles, it makes sense to stay in and fight the remaining primaries so the voters in those states can have a choice," he told me. Continued...