NORTH CHARLESTON, S.C. — As Democratic presidential candidates spoke at a breakfast for black ministers this week, Nina Turner — a campaign co-chair for Sen. Bernie Sanders (I-Vt.) who has been helping him connect with black voters — was interviewed by a television crew at the back of the room.

Felisha Woodberry took a Snapchat video of herself with Turner in the background and excitedly whispered: “The Nina Turner. THE. Nina. Turner.”

“Everyone I know who wants to know about Bernie, I tell them: Google ‘Nina Turner,’ look at her and what she’s doing,” said Woodberry, 40, who supported Hillary Clinton in 2016 and plans to vote for Sanders in the South Carolina primary Saturday. “A lot of candidates hire to pander. You can tell that Nina was not on the Bernie Sanders campaign to pander to black folk. . . . She’s standing because she’s meaning it, not because she’s getting paid to say it.”

Turner, a 52-year-old former state senator from Ohio, is Sanders’s most visible and passionate surrogate. She has been trying to help him win over black voters who largely spurned Sanders the last time he ran for president.

She opens for him at rallies, giving rousing, sermonlike speeches that pull together policy, tidbits of his biography and her own, lessons from the Bible and quotes from civil rights leaders. She often ends sentences with her signature call-out: “Hello, somebody!”

She goes after the senator’s rivals in ways he never would, writing that former vice president Joe Biden had “betrayed” black voters and harshly criticizing other candidates for their handling of racial issues. A major test of her efforts on Sanders’s behalf will come Saturday, when African Americans are expected to make up as much as 60 percent of South Carolina’s Democratic vote.

Four years ago, Sanders lost the state to Clinton by 47 points. His campaign has been aggressively organizing here for months in hopes of coming in at least a solid second place behind Biden, who has long had more support in black communities. Beyond collecting delegates, South Carolina could give Sanders the opportunity to show he can broaden his appeal and earn the support of more black voters, the party’s most dependable constituency and one that will probably be key to winning the general election.

Turner made South Carolina her top target. For months, she has been calling and meeting with state lawmakers, persuading several of them to endorse the senator or provide recommendations for hiring a diverse staff with roots in the state.

“I do lots of call time on behalf of the senator,” she said, “not fundraising call time, people-raising call time.”

For months, Sanders’s campaign has advertised in African American newspapers and on black radio stations and knocked on tens of thousands of doors. The senator has made nearly 20 trips to South Carolina since 2018, holding roughly 60 events, Turner said. She and other surrogates have visited black churches, rural communities that lack a hospital and barbershops.

Recent polls in South Carolina have been mixed, with some showing Sanders closely behind Biden and others showing Biden with a more expansive lead overall. In the last contest, in Nevada, Sanders received the most Latino votes of any candidate and grew his support from black voters, although he still trailed Biden. Sanders advisers point to these results as an indication that his efforts with nonwhite voters are working.

Turner is one of a cadre of black surrogates to the major presidential candidates, all of whom are white, but she’s also a senior member of Sanders’s staff and one of his highest-paid employees.

“How do I know Bernie Sanders? . . . I know him because I trust Nina Turner, and I talk to her,” the Rev. Al Sharpton said at the breakfast with black ministers. “If you don’t empower the blacks around you, you will not empower the black community.”

Turner met Sanders at a women’s leadership forum in October 2015, during his first presidential campaign. She had recently lost a race for secretary of state in Ohio, was working for the Ohio Democratic Party and had been an early supporter of Clinton’s candidacy. Onstage that day, Turner described herself as “a Mother Jones kind of girl,” someone who didn’t need a “fancy title” to get things done. The room fell silent as Turner told of her mother dying at age 42, reliant on government assistance and leaving behind seven children.

“When we have elected officials who do not understand they have to care about the least of these, it is personal for me,” she said that day.

Backstage she met Sanders, who told her: “I’ve been looking for you.” Three weeks later, he got her endorsement.

Since then, she has become a close adviser to a candidate who is famously a loner. She is nearly always on the campaign trail, only occasionally returning home to Cleveland to change out her suitcase and see her husband and son, who works in law enforcement. Turner has helped Sanders prepare for debates, which she then watches alone in a hotel room so she can prepare to face reporters in the “spin room” afterward. She has also educated him on the experience of growing up in poverty and being a black woman, especially a black mother with a black son, in America today.

“There’s a big difference in the communities that they come from. . . . Vermont is not the inner city of Cleveland,” said Chuck Rocha, a senior adviser to the campaign. “But you put both of those together, and you have all of America.”

When Turner’s mother died, she was 22, married with a baby and working low-paying jobs. She became “second momma” to her siblings, the youngest of whom was then 12. She enrolled in community college, and that eventually led into a series of jobs: African American history professor, city council member, state senator and unsuccessful statewide candidate.

She wants to be addressed formally: “First name, senator. Last name, Turner.” Her colleagues and friends call her “SNT,” short for Sen. Nina Turner, a job she held for five years.

In the presidential campaign she has become a celebrity of sorts, one easily spotted in a crowd — in a sea of black and navy at a Democratic Party dinner Monday night, she wore a regal polka-dot jacket over a long leopard-print dress with glittery sneakers.

Within minutes she can shift from giving a fiery speech to quietly listening to a voter share a heartbreaking story of how the health-care system failed. She hugs, she consoles, she cries along.

There are those who deeply love and admire her: At rallies, Sanders supporters sometimes chant her name. A young woman who took a year off college to work for the campaign had tears streaming down her face as she thanked Turner for inspiring her. Over the years, Turner has mentored many young black activists, candidates and lawmakers.

One is Cori Bush, who became politically active during the 2014 police protests in Ferguson, Mo., and has since run for office twice in Missouri and campaigned for Sanders in South Carolina.

“I was writing out a check for rent for the campaign office, but I didn’t have the money to pay my own rent, so I called her and told her: ‘I don’t think I can do this,’ ” Bush said. “She told me: ‘This is why you’re running. Just hold on, my sister, just hold on.’ She’s like a mother and a big sister and an auntie to everyone.”

And there are those who deeply dislike her: Some Democrats are still upset that Turner refused to endorse Clinton once she became the 2016 nominee. Green Party nominee Jill Stein — who is blamed by some for Trump’s win — had asked Turner to be her running mate; she declined. Turner has campaigned in South Carolina with actress Susan Sarandon, who endorsed Stein over Clinton. (Sarandon declined to comment, saying: “Maybe in the next state.”)

Between the two campaigns, Turner led Our Revolution, a political nonprofit that spun out of Sanders’s candidacy, and was accused of not raising enough money, promoting herself too much and protecting a staff member who publicly expressed frustration that there was so much sympathy for detained “illegal immigrants” but not for jailed African Americans.

In her current role as a campaign co-chair, Turner has been far more critical of Sanders’s rivals than he has. She referred to former New York mayor Mike Bloomberg as an “oligarch” and “racist” and demanded he drop out for supporting stop-and-frisk policing. She wrote in a January op-ed that Biden “repeatedly betrayed black voters to side with Republican lawmakers and undermine our progress,” referring to his past votes as a senator. She criticized former South Bend, Ind., mayor Pete Buttigieg for his handling of a police-involved shooting and mocked him for holding a fundraiser in a wine cave — wearing a T-shirt promoting the website peteswinecave.com, which redirects to a fundraising page for Sanders. She has accused many candidates of treating former president Barack Obama as a “prop.”

Sanders has faced questions about the nastiness of some of his supporters and, in response, he mentioned the “vicious, racist, sexist attacks” that Turner and other black staffers have faced.

Turner is regularly called sexist and racist slurs on Twitter, and accused of being an opportunist. Last year, a contributing editor for the liberal Daily Kos questioned Turner’s intelligence in a series of tweets and made a sexual comment about her and Sanders. Last weekend, a prominent West Virginia Democrat said in a tweet that Sanders should muzzle Turner or risk losing votes, then apologized and said his account had been hacked.

“It is okay for liberal Democrats to attack black women in America if we don’t agree with them,” Turner said on the Intercepted podcast taped Monday. “Our lives only matter and black women only lead when we’re doing exactly what you want us to do and saying exactly what you want us to say.”

Black women, she said, have to deal with these sorts of attacks “every single day of our lives, both covertly and overtly,” and tied that to their high rates of heart disease.

“There are so many microaggressions and stressors that black women are under that our hearts are broken — literally,” she said, her voice heavy with emotion. “All of the hell that we catch on a regular basis — whether it’s us worrying about ourselves as black women or worrying about the black children that we love, the black men that we love, the black communities that we love and carry on our shoulders and backs — is literally killing us.”

But she says her cause is worth enduring the stress. Ahead of Tuesday’s debate in Charleston, S.C., Turner stopped by a watch party and delivered a speech with many of the same lines she was using four years ago when she first met Sanders — including a joke about her grandmother storing money in her bra, calling it “the Southern Woman’s Bank and Trust.”

“We have been underestimated and disregarded,” she said, “but what all three early states have shown us is that we really do have a multi-gendered, multicultural, multiracial, conscious-minded coalition of people on the move.”

As the group cheered, Turner added: “Hello, somebody.”

Anu Narayanswamy contributed to this report.