It's the vexing issue hiding in plain sight.
"I know there are some people who won't vote for me because I'm black, and that's ok," said Democratic candidate Barack Obama.
Even as the economy seems to be in freefall, as Americans grapple with whether to vote for Obama, the first African American presidential nominee, or his Republican opponent, John McCain, it's a decision unavoidably colored by race, whether we like it - whether we admit it - or not.
When asked if race will affect a voter's decision, some say it is unavoidable, and that there are some voters who - issues aside - just aren't ready to cross that racial divide at the polling booth.
Barack Obama, the son of a white American mother and a black father from Kenya, says his race is not an issue for him.
"I self-identify as African American. That's how I'm treated and that's how I'm viewed, and I'm proud of it."
But his race is an issue for some Americans.
"I don't want to say I'm prejudiced or anything, but for one, I'm not going to, I don't want to vote for a colored man to be our president," said one voter.
"There are a group of people who will never, ever vote for Barack Obama," said Melissa Harris-Lacewell, a professor of politics and African American studies at Princeton University, and an Obama supporter.
"On the other extreme there are a group of white voters who are beside themselves with excitement about the idea of being in a multi-racial coalition led by a black candidate,' she said. "Then there is the vast middle. That group of voters are really the people that the Obama campaign is worried about making sure that the strategy is one about policy, about issues, about positions and not about questions of race."
Joe Trippi, a Democratic political consultant and an analyst for CBS News, says that Obama is running to be America's president, "not African-America's president or White-America's president, but everybody's president.
"And any time he gets sidetracked into defending or bringing up race, it doesn't help him."
In fact, race is a political hot potato that burns anyone who gets close. When Hillary Clinton said she more than Obama appealed to "hard-working Americans, white Americans," she was accused of exploiting the racial divide. When Sarah Palin tells her crowds Obama doesn't see America like they do, she says she means he's an elitist. Others hear racial code words.
… as when he is referred to at GOP rallies as "Barack Hussein Obama."
And when Obama said Republicans were trying to make voters afraid of him - remarking that the Democrat "doesn't look like all the other presidents on the dollar bill" - the McCain camp accused him of playing the race card.
Dan Bartlett, former counselor to President George W. Bush, now a CBS News political analyst, says the McCain campaign knows the boundaries.
"They've learned the lesson from the primary process with Bill Clinton and Hillary Clinton," Bartlett said. "And I think it's a simple lesson, that nothing really good comes out of even going up to the line, so to speak."
"But many whites thought the lines was crossed by the blistering language of Obama's former minister, The Reverend Jeremiah Wright - comments Obama said were not only wrong but divisive.
It forced the Senator from Illinois to tackle race in America head-on, in a speech last March in Philadelphia where he said, " I have asserted a firm conviction - a conviction rooted in my faith in God and my faith in the American people - that working together we can move beyond some of our old racial wounds, and that in fact we have no choice if we are to continue on the path of a more perfect union."
But that might be easier said than done.
For 10 years University of Washington social psychologist Anthony Greenwald has been studying "implicit bias," or unconscious attitudes. They don't control behavior, but they lurk in all of us.
Greenwald teases them out of the mind's deep recesses with a test (left) measuring rapid responses to flashing images. When it comes to Americans' attitudes on race, he found a widespread preference for whites.
"We find that 75% or so have this preference for white relative to black," Greenwald said.
What does that mean for the election?
"When voters are undecided, our test can pick up something that will predict how they will vote," he said.
David Sears, who studies polls at UCLA, has seen something similar. He calls it racial resentment - the belief of some whites that blacks complain too much, or don't try hard enough - attitudes they take into the voting booth.
"It turns out to be one of the strongest predictors of preference between Obama and McCain," Sears said. "I think there's reason to believe that Obama's not doing as well as a comparable white Democrat would do."
Still, Obama is ahead in the polls.
To Californians with long memories, it all sounds familiar. When Los Angeles Mayor Tom Bradley ran for governor in 1982, it appeared he was certain to become California's first black chief executive; the last polls had him up 10 points. Yet, he lost.
Joe Trippi was Bradley's deputy campaign manager.
"It was probably the most crushing defeat I've been part of."
"It gave us the term "the Bradley Effect" - the assumption that when it comes to black candidates, polls (or rather people who talk to pollsters) lie, fearing they'll be seen as bigots.
When Douglas Wilder ran for governor of Virginia in 1989 he was up 9 points, but squeaked to victory by less than one point.
What about Obama?
"The country has come a hell of a long way," Trippi said. "I think it's a mistake to think that there'll be any kind of big surprise like there was in the Bradley campaign in 1982. But I also think it'd be a mistake to say, 'It's all gone.'"
CBS pollster Kathleen Frankovic doesn't see it any more. In recent elections with black candidates - Deval Patrick's winning governor's race in Massachusetts, in Tennessee, Harold Ford losing his run for the Senate, both in 2006 - the polls were right-on.
"I really do believe that the so-called Bradley effect is an artifact of a certain place and a certain time," she said. "It's an artifact of the 1980s."
What's new? Frankovic says high-ranking blacks in the Bush White House have gotten Americans used to blacks in positions of authority.
Even pop culture has helped Americans entertain the idea of a black commander-in-chief.
Strong, successful black presidents in movies (Morgan Freeman in "Deep Impact") and TV shows (Dennis Haysbert in "24") may have set the stage.
fictionalized media allow us to try things on for size.
UCLA sociology professor Darnell Hunt, who has done research on race and the media, says fictionalized media "allow us to try things on for size.
"The media are pretty good at normalizing things, and if people see it enough in the media, suddenly it seems like something that, yeah, this can happen."
But this is the real world, with real world issues: two foreign wars, and an economy in deep crisis.
So what do voters say?
"But we've never had a black president before, so … (shrugs her shoulders)"
"I hope that people will get past race and just figure out which one of these guys is most, would be the best candidate for this country. This should supersede race."
"I don't care if he's green, white, black or purple - it doesn't matter, if they can perform and do the job, it doesn't matter to me."