CHARLESTON, S.C. — “I will tell you what my biggest desire is: that ‘Ronald Mc’Donald Trump does not make it in,” said Carol Hayes, a 58-year-old retiree with four young adult sons, ready to pile into a minivan with her extended family after church this past Sunday. “Hopefully if Hillary or Bernie makes it, they can make some changes with the Republican Congress we have in there now, and with the judges we’ll have to be nominating.”

As a black voter in South Carolina, Hayes is part of a key demographic that will affect the future of the Democratic race. African-Americans are 28 percent of the state population and a slight majority (55 percent) of the Democratic electorate. In South Carolina, black voter participation is generally higher than both the national and state average, according to data from the Current Population survey, perhaps because of a strong civic connection to voting among residents plus the state’s position as an important early contest.

Hillary Clinton is now considered to have a lock on the state (our primary forecasts say she has a greater than 99 percent chance of winning on Saturday, and she’s near 58 percent in the polling average). But her messages seem to resonate more with older black voters, raising questions about whether she’ll be able to turn out the younger black voters who supported President Obama in the last two elections. Bernie Sanders’s campaign, for its part, has a roster of high-profile black supporters, from Ta-Nehisi Coates to Spike Lee to Rep. Keith Ellison of Minnesota to former NAACP chairman Ben Jealous, but it’s not clear yet whether those endorsements and the campaign’s themes of economic equality and criminal justice reform will sway younger black voters, either.

While Hayes is voting Democratic, she’s torn between Sanders and Clinton. “Sanders has been saying some things that I really do like. But with her experience and her background, I think Clinton might have a little bit more pull when it comes to having changes done, and dealing with the Republicans,” she said.

I met Hayes at Sunday services at Charleston’s historic Emanuel AME Church, also known as Mother Emanuel, where she was cuddling a baby grandniece. From the civil rights era until today, Southern black churches like this one have often served as a place to celebrate the right to vote and organize the community to vote. This church is also where eight parishioners and the pastor were killed by a white supremacist last year. The fallout over the shooting led to Republican Gov. Nikki Haley’s decision to support and sign legislation taking down the Confederate flag from the state Capitol.

I attended Mother Emanuel’s services the morning after the GOP contest and less than a week out from the Democratic primary. From the pulpit, The Rev. Dr. Betty Deas Clark acknowledged the political moment and the presence of Melanie Campbell, the head of the nonpartisan National Coalition on Black Civic Participation. Campbell had just held a black women’s political roundtable in Columbia, the state capital, co-sponsored by Essence magazine and targeting young black women.

“When you talk about the black vote, you’re especially talking about black women,” Campbell said. Black women have the highest national voting rate, and Campbell says they are drivers of family voting behavior. “We are the secret sauce to get to the White House or the governorship or the mayors’ offices.”

Campbell said the organization’s research found affordable health care the top issue for black women of all ages, followed by living wage jobs and college affordability. Black millennial women also see criminal justice reform as a top issue.

Black men are a comparatively tougher group to get to the polls. Twenty percent of voters in the 2008 South Carolina Democratic primary were black men, according to exit polls, and they made up 11 percent of the state’s electorate in the general election that year. Black women, by comparison, were 35 percent of voters in the Democratic primary and 14 percent of voters in the general.

On Friday, I spoke to Azeez Aiken, a young member of the Central Mosque of Charleston and a local activist with the Pan-African Alliance. He voted for President Obama in 2008 and 2012 but said he’s not interested in what either party is selling this time around. “They’re trying to pimp the people into leaning one way or the other, and I see through the smoke and mirrors,” he said. “They’re using people to get ahead. And when they get the oath of office, they’re going to forget everyone who supported them.”

That attitude doesn’t sit well with Rep. Maxine Waters, a California Democrat who has been campaigning in South Carolina for Clinton — she held an event in Columbia on Saturday and we spoke by phone Sunday evening. “If he’s a Muslim, he should be one of the first people coming to the polls,” she said when I told her about meeting Aiken. “It is not acceptable in a democratic society to not support anyone.” Still, she said she isn’t worried about turnout among black millennials. “I’m not worried about how much they know now. Get involved. All you don’t know, you’ll learn.”

Celebrities, other Democratic members of Congress, including South Carolina Rep. James Clyburn, and Clinton herself are circling the state this week on her behalf. But the Sanders campaign seems to have moved on, quite literally. Although surrogates including Danny Glover remain in the state, Sanders is campaigning this week in Massachusetts, Virginia, Missouri, Oklahoma and Ohio.

When I wasn’t at church, I spent part of the weekend visiting campaign offices in Charleston. At one Sanders office, everyone was white. I spoke to Sanders staffers face to face and repeatedly followed up with others, including the state coordinator, by phone trying get an interview from a black volunteer or supporter. None was offered.

By contrast, when I went to a local Clinton headquarters, the staff and volunteers were a mix of black and white. While the staff skewed considerably younger, many of the volunteers were of retirement age. One of them, Helen A. Rivers, 71, was phone banking. A Charleston County native who was a medical intensive care nurse at the the VA hospital for 30 years, Rivers said she supported Clinton because “we need someone who would be fair to all races, not just one.”

The phone bank captain — in other words, a volunteer in charge of volunteers — was Pat Hardy, 64, who was born in New York but retired to South Carolina, where she has family. Hardy is a former schoolteacher and a lifelong Democrat who described supporting Clinton as common sense. “I want someone who can navigate the political world,” she said. “She’s been Secretary of State. No one else has that. She’s not namby-pamby. She’s a strong woman, and we need that.”

There was a mature but unmistakable hustle in the way the Clinton volunteers did intake and made phone calls, a grown but purposeful energy. Admittedly, hustle does not make one candidate’s platform better than another’s, but a tight ground game helps win campaigns. An analysis of the 2012 campaign by Paul A. Beck and Erik Heidemann found that Mitt Romney’s campaign had only slightly fewer contacts (including email, snail mail and social media) with voters than the Obama campaign did. But, says the report, “Needing to mobilize a base of young people and disadvantaged minorities who are commonly less motivated to vote, the Obama efforts understandably concentrated on face-to-face contacts,” which translated into success at the polls.

In 2012, voting rates for black Americans surpassed the voting rates for whites for the first time, with those ages 18 to 24 also voting at higher rates than their white counterparts, though black youth turnout was down from 2008. But the difference between black and white voting rates has often been overstated. To think of things another way, if Clinton wins as expected in South Carolina, white millennials may need as much TLC from the Sanders campaign as black ones. And Clinton will still face the challenge of motivating people like Carol Hayes and Azeez Aiken.

Ben Casselman and Harry Enten contributed research.