So much for post-racial politics.
Former U.S. president Jimmy Carter has reopened old wounds with his explosive claim that racism is at the root of a wave of anger directed at Barack Obama.
Mr. Obama's supporters say a white U.S. congressman's public heckling suggests many Americans aren't ready to accept the reality that an African-American is in the White House.
"I think that an overwhelming proportion of the intensely demonstrated animosity toward President Barack Obama is based on the fact that he's a black man," Mr. Carter, 84, told NBC television.
Mr. Carter's accusation mirrors comments by many liberal pundits and columnists after Republican lawmaker Joe Wilson shouted out "You lie" during Mr. Obama's prime-time speech to Congress last week.
"I live in the South, and I have seen the South come a long way," Mr. Carter added. "But that racism inclination still exists, and I think it has bubbled up to the surface because of a belief among many white people, not just in the South but across the country, that African-Americans are not qualified to lead this great country. It is an abominable circumstance, and grieves me and concerns me deeply."
This week, the U.S. House of Representatives voted 240-179 to reprimand Mr. Wilson, a South Carolina Republican.
Mr. Obama, however, has carefully avoided being drawn into the debate. He quickly accepted Mr. Wilson's apology. And yesterday White House press secretary Robert Gibbs dismissed the notion that race explains the angry opposition to its health-care proposals and corporate bailouts.
"The President does not believe that the criticism comes based on the colour of his skin," Mr. Gibbs insisted. "We understand that people have disagreements with some of the decisions that we've made."
Mr. Carter's comments echoed those of several prominent newspaper columnists.
Maureen Dowd of The New York Times suggested that Mr. Wilson's taunts show that Mr. Obama is "at the centre of a period of racial turbulence sparked by his ascension."
"This President is the ultimate civil rights figure - a black man whose legitimacy is constantly challenged by a loco fringe," she added.
And Washington Post columnist Colbert King similarly warned of "something loose in the land, an ugliness and hatred directed toward Barack Obama, the nation's first African-American president."
Recent protests by conservative, anti-big-government groups drew thousands to Washington, some carrying racially charged signs and slogans. One portrayed Mr. Obama as a witch doctor, and others said "I want my country back." Many demonstrators wore "I'm with Joe Wilson" T-shirts.
Conservatives counter that the charges of racism are a diversionary tactic to deflect attention away from Mr. Obama's troubled health-care reforms and sinking popularity.
"It's a mark of desperation to raise the race card when there's no evidence whatsoever that this was the issue," said Roger Pilon, director of constitutional studies at the Cato Institute in Washington.
"There's a real fear in the White House that this may be the end of his effort on health care."
Gil Troy, a professor of U.S. history at McGill University, said he sees little difference between the treatment of Mr. Obama and the way opponents attacked his predecessors, Bill Clinton and George W. Bush.
He pointed out that Mr. Clinton spent much of his presidency dealing with personal political attacks, while Mr. Bush was often branded a liar over his decision to invade Iraq.
"When Obama was elected, everyone was talking about how it was a sign of Americans' political maturity," Prof. Troy said. "To immediately start playing the race card the first time he runs into trouble is a mark of his supporters' immaturity."
If nothing else, the controversy makes it clear that Mr. Obama's political honeymoon is over, he added.
"His supporters are trying to demonize and marginalize normal politics. Conservatives do it to liberals. This time liberals are doing it to conservatives."
Others see something far more disturbing at work. Mr. Wilson's comments reflect growing fear and anger among Obama opponents, argued Gary Weaver, a professor of international relations and an expert on cross-cultural relations.
"Many people have a problem accepting the reality that there's a black guy in the White House," said Prof. Weaver, co-author of America's Midlife Crisis: The Future of a Troubled Superpower.
"They're angry and they're afraid that their way of life and their culture has been hijacked and it will never go back to what it was."
While there's nothing overtly racist in what Mr. Wilson did, it reflects a pattern of disrespect that most blacks would regard as subtle racism, according to Prof. Weaver.
"You can't tell what's in the heart of another person," he explained.
"You can't prove that it's racist. He didn't use the N-word. But for any black American who's over 40 years old, he's heard that kind of stuff before... being talked down to like a child."
The good news is that, by putting his cards on the table, Mr. Carter has created an opportunity to openly debate the issue of race.
"Gradually, Americans will get used to the fact that, yeah, we elected a black president of the United States, that he's competent, he's not a foreigner, he has a nice wife, a couple of kids and he's just like the rest of us," Prof. Weaver said.