Barack Obama now leads Hillary Rodham Clinton 43 percent to 24 in South Carolina, according to a Reuters/C-SPAN/Zogby poll conducted Jan. 20-22 and released today. Heading into Saturday’s Democratic primary, Obama has the clear advantage with African-American voters, men, and young voters, showing 65 percent support from black voters compared to Clinton’s 16 percent, and leading Clinton 50 percent to 19 percent among men, with only a slightly smaller lead for the 18-29 age group. Unlike in the New Hampshire and Nevada Democratic primaries, Obama has more support from women than Clinton does, leads her by 8 percentage points as he takes 37 percent.

Clinton previously had been polling in the high 20s and into the 30s as recently as last week in American Research Group and McClatchy-MSNBC surveys. Regarding the Zogby poll results from today, John Zogby says, “Like other states before, this race appears to be fluid…The question here in South Carolina is, if Obama wins South Carolina, will his win be big enough? If his lead is cut to single digits, given where this race has been in recent weeks, it stands to be a big victory for Clinton.”

John Edwards lags behind Obama and Clinton overall, pulling in just 15 percent of respondents, and finds almost no support from African-Americans. Edwards does not lead in any demographic category, and only challenges Clinton in support from white voters, 33 percent of whom favor Clinton and 32 percent of whom favor Edwards. Edwards is, once again, heading into a primary with a battle on his hands to pull in some of the undecided voters — this Zogby poll shows 14 percent undecided. If he does surge forward close to or past Clinton, it may signal a revival of his national campaign.

The poll of 811 likely Democratic primary voters has a margin of error of ‘3.4 percentage points.