WASHINGTON — For many Democrats, the 2008 presidential campaign is a celebration of those who once only dreamed of gaining power, with "you go, girl" cheers for Hillary Rodham Clinton and black pride in Barack Obama.

But as the top two candidates tap the excitement among Democrats over the prospects of a female or black president, a difficult question is confronting the field's No. 3 contender, John Edwards: What is a white man to do?

Edwards' status as a Southern, white male — characteristics that propelled Democrats Lyndon B. Johnson, Jimmy Carter and Bill Clinton to the White House — this year has offered some limitations, to the frustration of his campaign. "We can't make John black. We can't make him a woman," said Edwards' wife, Elizabeth, in one discontented moment this summer. "Those things get you a lot of press."

Now, as Edwards lays out the closing argument of his primary election campaign, that he is the most "electable" candidate and the most able to help fellow Democrats in conservative states, race and gender are forcing him to tread lightly.

Edwards' claims are sensitive, given that he is asserting he has more appeal to voters nationwide than do the front-runners, a white woman and a black man.

"He may not be saying it, but he's putting the argument out there that white male rural voters won't vote for a black guy or a woman," Taylor Marsh, a Democratic blogger and radio talk-show host, said in an interview. Marsh also recently raised the race and gender questions in a blog posting about Edwards' electability claims.

Garnet Coleman, a black state lawmaker from Texas, said Edwards was sending a subtle message about the risks of nominating someone who would be vulnerable to racism and sexism in the broader electorate.

"He's trying to make sure that when Democrats make a selection, they realize that the world is not perfect and they have to consider the long haul," said Coleman, who has endorsed Edwards based on his electability in the South.

"He has to be diplomatic," Coleman added. "He doesn't want to make it seem like he believes that an African American or a woman couldn't govern the country. It'd be real easy for someone to come out and say he's being insensitive to women and African Americans."

Coming from Edwards, who has campaigned to the left of Obama and Clinton, the electability claim is particularly eye-catching, because it seems to violate the traditional rule that the most electable Democrats are centrists. Some people also find it to be uncomfortably reminiscent of the coded language that was honed by the same Jesse Helms political machine that Edwards, a former senator, once defeated in North Carolina.

Edwards' advisers reject any suggestion that the electability claim is a special appeal to white voters or a statement that the nation would reject a woman or black man as president. Instead, they said, Edwards is claiming that he is less divisive than Clinton and more experienced than Obama.

And they contend that Edwards, thanks to his working-class roots in Robbins, N.C., is more in tune with the "culture" of rural voters. Moreover, they say Edwards is pushing a populist agenda that wins in the South.

Dave "Mudcat" Saunders, an Edwards strategist who specializes in attracting rural voters, charges that New York Sen. Clinton would bring "toxic coattails" and doom lower-level Democratic candidates in conservative areas. "It's not about women. It's about that woman," he said.

In recent days, Edwards has claimed that his candidacy could help Democrats win a "supermajority" in Congress, thanks to an ability to campaign in so-called red states that he honed with his 1998 win in North Carolina.

"I know what you have to do to win in battleground states, and to win in tough, tough congressional districts, and what you have to do to put out your message that works in those kind of places," he told NBC, adding later that, "I am the strongest candidate on the Democratic side in these battleground areas."