Tensions between Hillary Clinton and Barack Obama have spilled over into bad-tempered exchanges, mostly over the controversial role being played by the former president Bill Clinton in the election campaign.
The attacks, during the course of a televised debate on Monday evening, saw the candidates glare at and speak over one another. They exposed the deep animosity and growing competitive fury as the climax of the primary season approaches.
At one stage Mr Obama effectively accused the absent former president of lying to help his wife's campaign. "I'm here. He's not," Mrs Clinton snapped, in reply. "I can't tell who I'm running against sometimes," countered Mr Obama.
Mrs Clinton tried to paint her opponent as untrustworthy on issues, saying that his votes in the Illinois state senate had facilitated sex shops near schools and that he once worked as a lawyer for a "slum landlord". It was a church project, Mr Obama said, somewhat haplessly.
The debate also turned to disputed remarks Mr Obama made about Ronald Reagan in Nevada last week, for which he has been attacked. "I said that Ronald Reagan was able to get Democrats to vote against their economic interests to push through an agenda that I objected to," said Mr Obama. "While I was working on those streets [of Chicago] watching those folks see their jobs shift overseas, you were a corporate lawyer sitting on the board at Wal-Mart."
The debate returned to the subject of Bill Clinton when Mr Obama was asked to respond to the remarks by the Nobel Prize-winning black author Toni Morrison, who once observed that Bill Clinton "is our first black president, blacker than any actual black person who could ever be elected in our children's lifetime".
Praising Mr Clinton's affinity with black people, Mr Obama brought the house down with a remark that he would have to investigate more of Bill's dancing abilities, before judging "whether he was in fact a brother".
All day yesterday Mr Obama's complaint that he did not know who he was running against remained valid. Mrs Clinton flew back to Washington DC in the early hours, leaving the job of campaigning in South Carolina for the next few days to Mr Clinton and their daughter, Chelsea.
Mr Clinton's first campaign stop was at the Lizard's Thicket restaurant to meet voters and eat a Southern breakfast of "coffee, grits and eggs". He brushed aside Mr Obama's complaints. "I feel pretty chilled," he insisted, claiming he was just pushing back at "false and persistent criticisms of Hillary... There was nothing specific I said which was inaccurate," he said. "I try to be very careful about what I say and not to use too many adjectives."
But the bitterness of the feuding still hung over the campaign. It was all about "Bill" when the media finally caught up with Mrs Clinton. But she sidestepped the questions, calling them "totally off topic and off base... I think what we saw last night is that he's very frustrated – Senator Obama is very frustrated," she said.
Mrs Clinton has gone in search of votes for the bigger challenge ahead, when 22 states vote on 5 February. The expectation always was, that with its large Africa American electorate, South Carolina would go to Mr Obama. But given the excitement Mr Clinton generates when he travels around the state, even that is no longer a certainty.
* Fred Thompson last night quit the race for the Republican nomination. He failed to register in double figures in the early primaries and had pinned his hopes on a surprise win in South Carolina. Instead the state plumped for John McCain and the former Tennessee senator could now throw his support behind the frontrunner.
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