From left to right, Austin Jackson, Lawrence Nathaniel and Jennifer King smile as they check results on Jackson's phone from Bernie Sanders' Feb. 9 win in the New Hampshire primary. (Alex Holt/For The Washington Post)

The call-bank headquarters of Hillary Clinton’s campaign in this suddenly must-have state is in a small house on a tree-lined street not far from the Capitol. And, in a straight-from-central-casting display of Clinton’s core demographic of support, the first two volunteers inside the door are Eva Miller and Gloria Major, African American women who remember well the civil rights struggle.

“I am calling from the Hillary Clinton campaign. How are you today?” Miller, a retired worker from a nuclear plant, said pleasantly into the phone. “We’re talking with supporters like you who —”

She pauses.

“Well, thank you so much —”

Pause.

From left to right, Jason Perkey, Jamie Harrison and Trav Robertson watch the results of the Feb. 9 New Hampshire primary on a TV in the back room of Delaney's Music Pub and Eatery in Columbia, S.C. (Alex Holt/For The Washington Post)

“Well, you do that! Hillary will appreciate it, and so will I.”

She hangs up, smiling — another vote for Hillary in the Democratic primary on Feb. 27.

Across town, “shouting from the rooftops” for the Bernie Sanders campaign, is Wayne Borders, a 33-year-old African American and “child of the ’80s” who left his restaurant job in November to become a full-time canvasser. Dismayed by his memory of Bill Clinton’s years in office and inspired by Sanders’s progressive agenda, he’s committed to the Vermont senator.

“I’m knocking on doors all over town, informing people about a man who’s been an advocate for working people, for the disenfranchised, who helped Jesse Jackson win the state of Vermont in the ’80s,” he said. “He’s not just spouting words. He’ll do the work that needs to be done.”

As has been the case elsewhere, the contest in South Carolina is breaking down by age, with many of those over 45 supporting Clinton and those under more open to Sanders. What makes it different here — and in numerous states to follow — is that the fight is largely among African Americans, who are expected to make up at least half of the South Carolina electorate and who maintain a large degree of fondness for the Clintons.

Sanders is trying to cut into Clinton’s sizable lead by appealing to younger African Americans such as Borders, who are drawn to his message of economic justice and feel that many of the crime policies that began under President Bill Clinton have done long-term harm to their communities.

Demographics favor Clinton

The challenge for Sanders is steep: Many people here have come to know him only recently, if at all, and those he is counting on to rally to his side have not turned out to the same degree as their older counterparts.

In the 2008 South Carolina primary, with Barack Obama facing Clinton, about 60 percent of black voters were over 45. In the 2012 election, black turnout among those ages 18 to 29 was 53 percent. It was 66 percent among blacks 30 to 44 and more than 70 percent among blacks 45 and older.

“It’s according to age groups,” said Mattie Thomas, 66, a retired fast-food worker who lives in Lake City, about 25 miles south of Florence. She’s a Sanders supporter but concedes that most of her peers love the Clintons from Bill’s two terms in the Oval Office.

“They have a perception of the Clintons, and you’re not going to change their minds,” she said.

Another problem for Sanders: There are roughly 100,000 more African American women than men of voting age, and that demographic, particularly the older set, tends to skew heavily toward Clinton.

“The key demographic is African American women,” said ­Jaime Harrison, chair of the South Carolina Democratic Party. “Clinton has to maintain her support. Sanders has to do the ‘Carolina two-step’ ” — increasing his name recognition and then convincing voters he can deliver.

Both candidates sought to appeal to younger African Americans on Tuesday. In New York, after meeting with the Rev. Al Sharpton and other civil rights leaders, Clinton proposed new federal regulations that would end what she said were overly punitive school discipline policies that disproportionately affect minority students.

Speaking in Harlem, Clinton, without naming him, also accused Sanders of being a Johnny-come-lately to racial justice issues.

“You can’t just show up at election time and say the right things and think that’s enough,” she said to rousing applause. “You can’t start building relationships a few weeks before a vote and think that’s enough.”

Stepped-up outreach

Here in Columbia, Sanders stepped up his emphasis on criminal justice issues, saying, “We have got to achieve the day when young black males and women can walk the streets without being worried about being harassed by a police officer.”

Sanders was joined by Erica Garner, the oldest daughter of Eric Garner, whose death in New York after being in a police chokehold in 2014 helped inspire the Black Lives Matter movement. The senator also was accompanied by South Carolina Rep. Justin T. Bamberg, an African American who serves as the attorney for the family of Walter Scott, an unarmed black motorist who was shot to death last April by a North Charleston, S.C., police officer.

The Sanders campaign is relying on state legislators such as Bamberg who have endorsed him to help spread the word, along with an eclectic group of black surrogates who are expected to be increasingly visible as the primary approaches. They include Benjamin Jealous, 43, who was the youngest leader of the NAACP; Atlanta-based rapper Killer Mike; actor Danny Glover; entertainer and civil rights activist Harry Belafonte; and academic Cornel West.

The campaign is paying “dozens” of canvassers $15 an hour to go door to door, primarily in the African American community, to pitch Sanders’s candidacy, according to campaign manager Jeff Weaver.

“Our outreach program in South Carolina is sort of a neighbor-to-neighbor outreach program,” Weaver said.

Sanders has also been airing ads on black-oriented radio stations and is on television with spots that highlight his commitment to civil rights. In one, a narrator reminds viewers that Sanders participated in the 1963 March on Washington as a college student and says he wants to end racial profiling, combat police misconduct and dismantle private prisons.

“A lot of these people are undecided, or they want to know why they shouldn’t vote for the household name of ‘Clinton,’ ” said Bree Maxwell, a 31-year-old Sanders volunteer in Richland County who frequently goes to colleges for speaking events to pursue young voters. “But they’re very receptive. The older voters are the ones who give me the hardest time.”

Chris Covert, South Carolina director for Sanders, said the campaign has just opened its 11th field office in the state and has had more than 1,000 volunteers sign up since Sanders’s stronger-than-expected performances in Iowa and New Hampshire.

“Time is always a challenge for us, but we’re in good position to make a run,” he said.

One advantage Sanders may have is that voters are allowed to register on primary day, meaning he could, at least theoretically, take advantage of late-coming support.

In the past week, Clinton has locked up endorsements from the political arm of the Congressional Black Caucus and influential state politicians such as Todd Rutherford, the House minority leader. Celebrity endorsers Vivica Fox and Angela Bassett have been barnstorming the state. Clinton is slated to be at South Carolina State, a historically black university, later in the month.

‘Relationships that last’

Her campaign workers here said they have been working the state since the spring. “We’ve had offices on the ground in South Carolina since last April,” said Stephanie Formas, Clinton’s in-state communications director, “and we’ve been forming long-term relationships that last.”

For Major, a retiree and one of the volunteers at the Clinton phone bank, making calls two nights a week is an opportunity to make a difference and to set an example of political involvement for her grandchildren.

“Bernie has a passionate, motivational speech that draws young people,” she said, taking a respite from her call sheet. “What I love about Hillary is her facts. Her reality. She’s not selling you a white picket fence. She’s selling you things that she can deliver.”

Bamberg, who is 28, said he decided to support Sanders after having a chance to talk with him during a Martin Luther King Jr. celebration in Columbia.

“Things are picking up, and Bernie’s name is coming up in every conversation,” he said. “It’s going to be a lot closer than people ever believed it could be.”

Vanessa Williams, Anne Gearan, Janell Ross and Alice Crites in Washington contributed to this report.