former US President Jimmy Carter claimed last night that many of Barack Obama's most vocal critics were racist.
He said they had been spurred into bitter attacks on his policies by their revulsion at the election of America's first black president.
In a blistering attack on the right after watching Mr Obama endure a summer of hostility, he singled out Joe Wilson, the congressman who shouted "you lie" while Mr Obama was making a speech on healthcare to the US Congress last week.
That attack, Mr Carter alleged, was also "based on racism".
He said: "I think that an overwhelming proportion of the intensely demonstrated animosity toward President Barack Obama is based on the fact that he is a black man, he's African American.
"I live in the South, and I have seen the South come a long way," said Mr Carter, a native of Georgia.
"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."
Mr Carter has become the most prominent voice to level a direct charge of racism at Mr Obama's critics and the comments could provoke a contentious debate on race that the White House is eager to avoid.
It has emerged since last week that Mr Wilson was among a small group of Republicans who supported a campaign to keep the Confederate flag flying over South Carolina's capitol building.
The flag is regarded by African Americans, and many others, as a symbol of the pro-slavery South.
Mr Wilson's son, Alan, said yesterday: "There is not a racist bone in my dad's body. He doesn't even laugh at distasteful jokes. I won't comment on former President Carter, because I don't know President Carter. But I know my dad, and it's just not in him."
Opponents have compared Mr Obama to Hitler, the Joker from the 'Batman' films and the Antichrist.
They have also called him a Nazi, a socialist, a communist and questioned his nationality.
Demonstrators toting guns have appeared outside the president's town hall appearances while a handful of preachers have led congregations in prayers that Mr Obama would die.
"Those kind of things are not just casual outcomes of a sincere debate on whether we should have a national programme on healthcare," said Mr Carter. "It's deeper than that."
Robert Gibbs, the White House spokesman, said: "I don't think the president believes that people are upset because of the colour of his skin."
His remarks demonstrated the administration's keenness to bury a debate that would divert attention from the president's already overloaded agenda.
Organisers of the conservative "tea party" protests against the president have insisted their opposition is based merely on dislike of his "big government" policies. (© Daily Telegraph, London)