His next-closest opponents in South Carolina are Sen. Elizabeth Warren, at 17 percent, and Sen. Bernie Sanders at 15 percent in the CBS poll.

In the Quinnipiac poll, Biden has 33 percent support and Warren and Sanders are at 13 and 11 percent, respectively. In the UNF survey, Biden registers 36 percent support, with Warren and Sanders tied at 10 percent.

The polls bolster claims by Biden’s allies that he’s the only candidate in the race who can point to a broad base of support with a pillar of the Democratic Party – African-Americans.

Their continued backing is essential to Biden’s bid — particularly in the South — since black voters could account for one-in-four total voters during primary season. High black turnout is also crucial to any Democrat’s chances in a general election.

While Biden is benefitting from his status as vice president to the first black president, his longstanding ties to South Carolina and the attacks on his character by Donald Trump have also reinforced his position, according to state Sen. Marlon Kimpson, a Democrat from North Charleston who is neutral in the race and has hosted numerous candidates in his majority-black district.

“Ironically, Trump has helped Biden here,” Kimpson said.

“People I talk to believe Biden doesn’t get a fair shake. And there’s some ownership of him. He has been friendly to our state. He was President Obama’s vice president. There’s sort of a feeling of kinship with him,” Kimpson said. “And people don’t like folk picking on their relative. They believe Joe is an uncle to our state. And Trump’s preoccupation and fascination with taking him out has resonated.”

“Ironically, Trump has helped Biden here.” South Carolina state Sen. Marlon Kimpson.

Kimpson and the pollsters cautioned that the race is still fluid and anything can still happen. The surveys show that many voters have indicated they could switch their votes. There’s also a sizable pool of undecided voters, about a fifth of the state electorate

“If Biden goes into Atlanta in the debate this week and says something stupid, well, he can’t afford any major problems,” Kimpson said.

The newest polls are a gut-punch to the two African-American senators who have looked to the state as a springboard, Kamala Harris and Cory Booker. They’ve premised their candidacies on doing well enough in Iowa, New Hampshire or Nevada in order to gain momentum and capture the support of South Carolina’s black voters -- estimated to be as much as two-thirds of the primary vote in the state.

The senators’ calculus also counts on the implosion of Biden’s campaign, which has so far failed to materialize.

Harris only has 3 percent overall support in South Carolina and 6 percent support from black voters there, while Booker has 2 percent support overall and from black voters in the state, according to Quinnipiac’s survey. In UNF’s poll, Harris has 4 percent overall support and also from black voters, while Booker is at 2 percent in both categories.

UNF surveyed 437 Democratic voters by cell and landline phones for its poll, which has a margin of error of +/- 4.7 percentage points. Quinnipiac surveyed 768 likely voters by cell and landline phones. And CBS surveyed 933 Democrats in the state via internet-based web panels. CBS/YouGov did not provide detailed breakdowns of poll respondents by race.

The polls suggest South Carolina, the final early state to vote on Feb. 29, is an uphill climb for Pete Buttigieg, the mayor of South Bend, Indiana, who is the leader in a recent flagship poll in Iowa.

In the UNF survey, Buttigieg had 3 percent support overall and 1 percent support from African-American voters. In Quinnipiac’s poll, Buttigieg registered no support among black voters and was at 6 percent overall.

“It’s certainly a warning sign for all of the other candidates,” UNF political science professor Michael Binder said, referring to the preferences of black voters so far.

Binder cautioned that early polls like this will change as the campaign grinds on and candidates win or lose in the early states. But at the moment, Biden’s support shows how strong he is with black voters.

“Biden right now is the toughest kid on the block in South Carolina and until someone comes along and punches him in the nose, he’s going to stay that way,” Binder said.