Obama dips but still has big South Carolina lead

By John Whitesides, Political Correspondent

FLORENCE, South Carolina (Reuters) - Democrat Barack Obama's big lead over rival Hillary Clinton has slipped but is still substantial two days before the presidential primary election in South Carolina, where candidates were competing vigorously to win support from black voters.

Former President Bill Clinton, whose wife is battling with challenger John Edwards to stay out of third place in South Carolina, lashed out at Obama and the media for elevating race in the campaign.

Obama's lead fell 3 points overnight to give him a 39 percent to 24 percent edge over Clinton in South Carolina, according to a Reuters/C-SPAN/Zogby poll released on Thursday.

Edwards, a former senator from neighboring North Carolina, climbed four points to reach 19 percent -- within striking distance of Clinton and second place.

The poll has a margin of error of 3.4 percentage points.

The shifts have occurred since Monday night's angry debate in Myrtle Beach, where Obama and Clinton traded harsh accusations about their records and Edwards chastised the pair for squabbling.

Since then, Obama and Clinton have cranked up their bitter fight for the Democratic nomination in November's election to succeed President George W. Bush. Both candidates prepared harsh radio ads in South Carolina on Wednesday attacking each other.

Bill Clinton said on Wednesday it was unfair that the former first lady had been accused of "playing the race card" in the campaign.