Obama dips, but still has big South Carolina lead

FLORENCE, S.C. - Democrat Barack Obama's big lead over rival Hillary Clinton slipped slightly but is still substantial two days before South Carolina's presidential primary, according to a Reuters/C-SPAN/Zogby poll released on Thursday.

Obama's lead dipped three points overnight to give him a 39 percent to 24 percent edge over Clinton in the rolling tracking poll. John Edwards climbed four points to reach 19 percent -- within striking distance of Clinton and second place.

US Democratic presidential candidate Senator Barack Obama (D-IL) talks to voters during a campaign stop at Dillon High School in Dillon, South Carolina, January 23, 2008. (REUTERS/Jonathan Ernst)

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.

"Since the debate, Obama and Clinton have dropped and Edwards has been rising," said pollster John Zogby. "There is definitely some movement here."

Obama's dip came largely among black voters, who are expected to make up more than half of the Democratic primary electorate in South Carolina on Saturday.

Support for Obama, an Illinois senator who would be the first black U.S. president, fell from 65 percent to 56 percent among African-Americans, with Clinton climbing two points among blacks to 18 percent.

Edwards held a slight lead over Clinton among likely white voters at 35 percent to 32 percent. Obama had 19 percent.

EDWARDS CLIMBS

In the last of the three days of polling on Wednesday, Edwards led Clinton for second place and has been climbing steadily each day.

"If the trajectories continue, it's within the realm of possibility that Clinton could come in third," Zogby said.

Clinton, a New York senator who would be the first woman U.S. president, came in third behind the winner Obama and Edwards in Iowa, but bounced back with wins in New Hampshire and Nevada heading into the showdown in South Carolina.

Obama has spent the past two days on a bus tour of South Carolina, while Clinton has been out of the state campaigning in California, Arizona, Pennsylvania and New Jersey ahead of the Feb. 5 "Super Tuesday" round of contests in 22 states.

About 13 percent of voters in Saturday's primary say they are still not sure who to support. "That's a lot for three candidates who are this well known," Zogby said.

Obama led among most sub-groups, including men, women, liberals, conservatives, young, low-income, and union household voters. Clinton edged Obama out among the oldest voters, above age 70. Edwards led Obama among Republicans.

The rolling poll of 811 likely Democratic voters in South Carolina was taken Monday through Wednesday. In a rolling poll, the most recent day's results are added while the oldest day's results are dropped in order to track changing momentum.