With two days to go until South Carolina holds the first Southern primary in the race for the White House, a new poll shows Joe Biden holding a large lead over front-runner Sen. Bernie Sanders in a state the former vice president sees as a firewall for his struggling presidential campaign.

Biden stands at 36 percent support among likely Democratic presidential primary voters, according to a Monmouth University poll released on Thursday, with Sanders at 16 percent and billionaire hedge fund manager-turned-environmental advocate Tom Steyer at 15 percent.

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Sen. Elizabeth Warren of Massachusetts stands at 8 percent in the survey, with former South Bend, Ind., Mayor Pete Buttigieg at 6 percent; Sen. Amy Klobuchar of Minnesota at 5 percent; and Rep. Tulsi Gabbard of Hawaii at 1 percent. Fifteen percent of those questioned said they remained undecided ahead of Saturday’s primary.

The poll’s release came one day after longtime Rep. James Clyburn – the dean of Palmetto State Democrats – endorsed the former vice president. The endorsement of Clyburn, the most senior black politician in the state, was seen as a boost for Biden.

“Biden appears to be holding on to his core support among African-Americans in South Carolina,” Monmouth University Polling Institute Director Patrick Murray said.

Thanks to his eight years as vice president under President Barack Obama, America’s first black commander-in-chief, Biden remains popular with African-American voters. And after disappointing fourth- and fifth-place finishes in the predominantly white states of Iowa and New Hampshire, Biden’s campaign is predicting a victory in South Carolina – where roughly 60 percent of the Democratic presidential primary electorate is black.

The poll indicates Biden earning the support of 45 percent of black voters, with Steyer at 17 percent and Sanders at 13 percent. White voters were more divided, with Biden at 26 percent, Sanders 17 percent, Warren and Buttigieg each at 13 percent and Steyer at 12 percent.

Just 4 in 10 of those polled said they were firmly behind the candidate they’re currently supporting, but Murray noted: “A key metric for Biden in this make-or-break state is that his support appears to be firm. There is still a large chunk of the electorate who are undecided, but they are mainly moderate black voters. That’s a group that tends to like Biden.”

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The Monmouth University poll was conducted Feb. 23-25, mostly before Wednesday night’s combative Democratic presidential primary debate in Charleston. Live telephone operators questioned 454 likely Democratic presidential primary voters in South Carolina, with a margin of error of plus or minus 4.6 percentage points.

Two other polls released in recent days indicated Biden with a large double-digit lead over his 2020 rivals in South Carolina – but three other surveys pointed to the former vice president holding on to a slim single-digit advantage over Sanders, who narrowly won the New Hampshire primary before blowing out the rest of the field in last weekend’s Nevada Caucuses.