(Agencies)
Updated: 2008-01-26 19:20

COLUMBIA, S.C. - In a Democratic primary sure to attract a large number of black voters, race remained a persistent subtext as Barack Obama found himself going up against two Clintons.

Democratic presidential candidate Senator Barack Obama (D-IL) speaks during a campaign stop at North Charleston High School in North Charleston, South Carolina January 24, 2008.  [Agencies]

South Carolina became a "must win" state for Obama, whose victory in the Iowa caucuses Jan. 3 began to fade after he lost contests in Nevada and New Hampshire to Hillary Rodham Clinton. A win here on Saturday could help reinforce Obama's co-frontrunner status with Clinton, while a loss would severely imperil his candidacy.

Polls showed Obama favored to win the state in large part due to his strong support among black voters, who are expected to comprise more than 50 percent of the electorate. The Illinois senator is running to be the first black president.

The state Democratic Party chairwoman, Carol Fowler, predicted a record turnout.

Obama has made a direct appeal to blacks here after rarely mentioning race throughout the campaign. He'll continue that strategy going forward, making trips to Georgia and Alabama later this weekend. Both states hold primaries on the multistate "Mega Tuesday" contest Feb. 5 and feature a significant number of black voters.

For her part, Clinton was already looking ahead to Feb. 5 even as the South Carolina primary loomed. She campaigned in California, Arizona and New Jersey early in the week before returning to South Carolina on Thursday. She was headed to Tennessee after the polls close here Saturday.

With his wife's attention directed elsewhere, Bill Clinton stepped into a starring role in South Carolina, aggressively challenging Obama's record while scolding the media for what the former president said was unfair coverage of the contest.

Widely popular among black voters, Bill Clinton complained that reporters cared too much about the racial aspect of the campaign even as he predicted Obama would win here because of his race.

His high-profile role left Obama to complain that he didn't know which Clinton he was running against.

John Edwards, who has pinned his fading hopes on his native South Carolina, campaigned actively in the state throughout the week. The former North Carolina senator won the state's primary in 2004, but polls showed him running a distant third to Obama and Clinton.

The run-up to the primary was noteworthy for its nasty tone from a rancorous televised debate early in the week to the first negative ads of the campaign.

Clinton and Obama clashed bitterly in a televised forum Monday in Myrtle Beach, chiding one another on issues of character and trustworthiness. Edwards tried to rise above the rancor while pleading for equal air time.

The two leading candidates also squared off in a pair of radio ads - Clinton's challenging Obama's claim that Republicans were once "the party of ideas," and Obama's saying the former first lady would "do anything" to be elected. The ads stayed up only briefly.