But a new AP-Yahoo News poll shows that race could also play a big role in how some voters make their choice - and this may not bode well for Barack Obama.
According to the poll released Saturday, a little over one-third of white Democrats and independents agreed with at least one negative adjective about blacks, and they are less likely to vote for Obama than those who don't hold such views.
"There are a lot fewer bigots than there were 50 years ago, but that doesn't mean there's only a few bigots," said Stanford University political scientist Paul Sniderman, who helped analyze the exhaustive survey.
The pollsters set out to determine why Obama is locked in such a close race with Republican presidential candidate John McCain even as the political landscape seems to favor Democrats; President George W. Bush's unpopularity, the Iraq war, and a national sense of economic hard times cut against Republican candidates, as does the fact that Democratic voters outnumber Republicans.
Lots of Republicans harbor prejudices, too, but the survey found they weren't voting against Obama because of his race. Most Republicans wouldn't vote for any Democrat for president - white, black or brown.
The survey also focused on the racial attitudes of independent voters because they are likely to decide the election.
The poll does show that many whites who see blacks in a negative light are still willing (or even eager) to vote for Obama. But statistical models derived from the poll suggest that Obama's support would be as much as 6 percentage points higher if there were no white racial prejudice.
However, a CBS/New York Times poll released earlier this week showed that Obama holds a two point edge over McCain among all white women, making a 21-percentage point swing in Obama's favor from the previous week.
On the other side of the racial question, the poll shows the Illinois Democrat is drawing almost unanimous support from blacks.
But a sign that the economy may trump prejudice comes in the telling result from the question, "Would you say things in this country are heading in the right direction, or are they off on the wrong track?" Among ALL voters, 72 percent said the country was on the wrong track; only 27 percent said the U.S. was headed in the right direction.
Other findings in the polls, among ALL voters: 54 percent had "very favorable" or "somewhat favorable" impressions of Obama, compared to 50 percent for McCain. The "very favorable" response for Obama (30) was more than twice that of his rival (13).
Favorable impressions for the Democratic Party were also generally higher than for the Republicans.
And how do voters characterize the candidates? When offered a list of adjectives describing each candidate, those most frequently chosen for Obama were "Intelligent" (61%), "Popular" (58%), "Will bring about change" (51%), "Inexperienced" (47%), and "Honest" (36%).
For McCain the most frequently picked adjectives were "Experienced" (58%), "Strong military leader" (49%), "Intelligent" (47%), "Courageous" (44%), and "Past his prime" (36%).
The poll used a methodology developed by Knowledge Networks, a Menlo Park, Calif., firm that interviews people online after randomly selecting and screening them over the telephone. (Numerous studies have shown that people are more likely to report embarrassing behavior and unpopular opinions when answering questions on a computer rather than talking to a stranger.)
Other techniques used in the poll included recording people's responses to black or white faces flashed on a computer screen; asking participants to rate how well certain adjectives apply to blacks; measuring whether people believe blacks' troubles are their own fault; and simply asking people how much they like or dislike blacks.
The poll sought to measure latent prejudices among whites by asking about factors contributing to the state of black America. One finding: More than a quarter of white Democrats agreed that "if blacks would only try harder, they could be just as well off as whites."
Those who agreed with that statement were much less likely to back Obama than those who didn't.
Among white independents, racial stereotyping is not uncommon. For example, while about 20 percent of independent voters called blacks "intelligent" or "smart," more than one third latched on the adjective "complaining," and 24 percent said blacks were "violent."
Nearly four in 10 white independents agreed that blacks would be better off if they "try harder."
Researchers used mathematical modeling to sort out the relative impact of a huge swath of variables that might have an impact on people's votes - including race, ideology, party identification, the hunger for change, and the sentiments of Sen. Hillary Clinton's backers.
Just 59 percent of her white Democratic supporters said they wanted Obama to be president. Nearly 17 percent of Clinton's white backers said plan to vote for McCain.
The survey of 2,227 adults was conducted Aug. 27 to Sept. 5. It has a margin of sampling error of plus or minus 2.1 percentage points.
Pollster Frank Luntz said that race can affect what voters tell polltakers, as was evident in exit polling during the primaries.
"In the states that were north of the Mason-Dixon line and east of the Mississippi River, states like Ohio and Pennsylvania, they got the exit polling numbers wrong because people said 'I voted for Barack Obama,' but, in fact, they voted for Hillary Clinton,' Luntz told Early Show anchor Erica Hill.
Luntz said, in fact, voters in the South were more likely to be honest with poll takers about whom they voted for when race was part of the mix.
Luntz did say, however, that pocketbook issues may trump prejudice, saying he believes Obama will take Pennsylvania, a state he lost to Clinton, despite heavy spending there by the Republicans.
"Barack Obama has proven he does well in the suburban vote, and the suburbs of Philadelphia and the suburbs of Pittsburgh, I think, will put Obama over the top," Luntz said.
And perhaps most telling that prejudice - or even long-held party loyalty - may not trump the economy for voters: In Indiana, which has been a safe state for Republicans for years (George W. Bush beat John Kerry 60 percent to 39 percent), McCain leads Obama by only six points, according to a CNN/Time poll.