Race has bedeviled this country from the start, when the Founding Fathers ducked the slavery issue for fear of killing the nation in its cradle.
Obviously, much has changed. For one thing, Americans are seriously weighing the prospect of elevating a black man to the White House in November.
But as this past week's debate over "the race card" illustrates, there is still no subject in American politics as fraught as the color of a candidate's skin.
Angered by remarks Barack Obama made to an audience in rural Missouri, Sen. John McCain of Arizona, who is white, accused the Illinois senator, who is black, of using race as wedge to win support.
Democrats accused McCain of cynically turning things on their head; by crying foul, they claimed, McCain managed to put race front and center just as he was stepping up his personal attacks on Obama.
Both candidates stand to gain -- and lose -- from the testy back-and-forth, underscoring just how incendiary, and complex, racial politics remain more than 200 years after vexing the first set of American politicians.
"It is not to Barack Obama's advantage to make this a big issue," said Dan T. Carter, a history professor at the University of South Carolina, who has written extensively about race and politics. At the same time, McCain cannot afford to be seen as exploiting racial tensions for political gain, Carter said: "It is simply not acceptable to the majority of people, including many of those who may be sympathetic."
That may explain why the candidates acted the way they did: Obama ignoring McCain and leaving his initial response to aides -- who quickly shifted the subject to the economy and foreign policy -- and McCain portraying himself as the victim of a rhetorical mugging.
(On Saturday, Obama called the comments from the McCain camp an effort "to distract people from talking about real issues." McCain told reporters on Friday he was "ready to move on.")
Race has been a subtle issue in the presidential contest all along. That was inevitable, given the historic nature of Obama's campaign and his background as the son of a black man from Kenya and a white woman from Kansas. (With his biracial background, Obama gets it coming and going; on Friday his town hall meeting in Florida was interrupted by protesters claiming he has been neglectful of the black community.)
The two candidates have for the most part steered clear of open racial appeals. But that changed, McCain aides say, when Obama mentioned his Republican rival and condemned GOP scare tactics in the same breath.
"Nobody really thinks that Bush or McCain have a real answer for the challenges we face," Obama told the Missouri crowd, predicting Republicans would question his patriotism and highlight his unusual name and the fact that he doesn't "look like all those other presidents on those dollars."
The statement was similar to comments Obama has made before. But this time the McCain campaign responded sharply. "Barack Obama has played the race card . . . from the bottom of the deck," campaign manager Rick Davis said in a written statement, which McCain subsequently endorsed.
McCain aides called the response a matter of personal honor, since Obama mentioned his opponent by name. Democrats called it an excuse -- a long-awaited one -- to inject race into the campaign.
Whoever picked the fight, neither side has clean hands.
Obama benefited in the Democratic presidential primary from anger stirred by suggestions that his rival, Sen. Hillary Rodham Clinton of New York, and her surrogates were using race to appeal to white voters. Although Obama never explicitly made that case -- and usually works to downplay his ethnicity -- he is thought to be counting on strong black support in November to win battleground states such as Michigan and Pennsylvania, and to put Republican-leaning states such as North Carolina and perhaps even Georgia into play.
"Race plays a role in American politics in a lot of different ways. It's not just Ku Klux Klan-style racism," said Vincent Hutchings, a University of Michigan specialist on the intersection of race and politics. "When a large number of African Americans decide to support Barack Obama on the assumption he'd be a better vehicle for pursuing their interests, that's taking race into consideration."
McCain, for his part, has made an effort to reach out to black audiences. On Friday he spoke to the Urban League, and last month he addressed the National Assn. for the Advancement of Colored People. He has condemned inflammatory statements made by supporters, including a Cincinnati radio host who incited a crowd with cracks using the Democrat's full name, Barack Hussein Obama.
But Republican candidates have a history of playing on prejudice, particularly in the South, both openly and through the use of political code words and suggestive images.