For decades, ambitious politicians with eyes on a future presidential run made pilgrimages to Iowa and New Hampshire, casually popping in at fairs and local fund-raising dinners as if they just happened to be in the area.
When President Biden pushed Democrats to place South Carolina first on their presidential primary calendar, the geography for the party’s political strivers changed. They are now working to build support not in mostly white Northern places but in a Southern state with a predominantly Black primary voting base that better represents the modern Democratic Party.
So when Vice President Kamala Harris arrived on Friday in Orangeburg, S.C., for her ninth visit to South Carolina since taking office, she came as a known quantity. While she and Mr. Biden are running for renomination without serious challengers, the relationships she has developed in the state are expected to play a part in lifting their ticket to a comfortable triumph on Saturday in the party’s first recognized primary election.
Ms. Harris’s trip, as well as an ongoing college tour to defend abortion rights and promote the Democratic agenda, also served two larger purposes: working to shore up Mr. Biden’s lingering vulnerabilities with Black voters and young voters, and keeping the first woman and first woman of color to serve as vice president at the forefront for the next presidential contest in 2028.
Perhaps the most influential Democrat in South Carolina is already on board with Ms. Harris as a future White House candidate.
“I made very clear months ago that I support her,” said Representative James E. Clyburn, whose 2020 endorsement of Mr. Biden before his state’s primary election helped rejuvenate the former vice president’s struggling campaign and carry him to the nomination. “That’s why we got to re-elect the ticket. Then you talk about viability after that.”
Ms. Harris, who ended her 2020 presidential campaign months before the South Carolina primary, has sought to deepen her ties here.
“There is an unspoken language between the vice president and African American women in this state,” said Trav Robertson, a former chairman of the South Carolina Democratic Party. “She doesn’t have to go into a room and say things — because they already know they have a shared experience.”
Ms. Harris was part of a parade of Biden campaign surrogates who have trekked to South Carolina to stump for the president in a primary whose result is hardly in question. Mr. Biden’s competition is Representative Dean Phillips of Minnesota, who is little known and has spent nothing on television ads in the state, and the self-help author Marianne Williamson, who attracted minimal support in the New Hampshire primary even without Mr. Biden on the ballot.
No one has energized more voters in South Carolina than Ms. Harris, who is positioned as a natural successor to Mr. Biden but tends not to surface at the top of Democratic wish lists for 2028 presidential candidates. On Friday in Orangeburg, S.C., she met with a group of local pastors, some of whom she has yearslong relationships with; stood for a photo line that included supporters of her 2020 campaign; and spoke at a final rally before the primary.
Her local connections were clear. Jaime Harrison, an Orangeburg native who serves as chairman of the Democratic National Committee, called her “our M.V.P.” Mr. Clyburn, from the stage, affectionately called her “my girl.”
“In 2020, it was South Carolina that put President Joe Biden and me on the path to the White House,” she told the crowd. “It is because of that work that Joe Biden is president of the United States and I am the first woman and first Black woman to be vice president of the United States.”
The Biden campaign has hired a local staff of four people and encouraged visits by supportive politicians, ranging from the well known (Gov. Gavin Newsom of California) to the somewhat known (Mitch Landrieu, the former mayor of New Orleans) to the little known (Lt. Gov. Austin Davis of Pennsylvania).
Mr. Davis spent Wednesday stumping for Mr. Biden at six stops across South Carolina. Mr. Davis, who is just 34 and is Black, volunteered his time for the campaign to pitch its message to young Black men — an audience that polls show is skeptical of backing the president.
Mr. Davis acknowledged in an interview that he was a new face in South Carolina.
“By the end of my speech, I had a lot of fans,” he said. “I think they were like: ‘Oh, we’re glad you showed up. We had no idea who you were, but we’re glad you showed up.’”
Some surrogates have sought to motivate Democratic voters by warning that Republicans pose a threat to them. Speaking on Tuesday to Black voters in Ridgeland, S.C., Mr. Landrieu alluded to “rhetoric” on the right that sometimes includes racist messaging.
“You’re from the South — you hear those dog whistles like a train coming down the track,” he said. “Some people say they want to make America great again. I’ve got news for y’all: America’s great already.”
“Always was,” a woman in the crowd yelled back.
The push to bolster Ms. Harris’s political prospects extends beyond her efforts to ingratiate herself with voters who are likely to have outsize influence on picking the 2028 Democratic nominee.
The Democratic fund-raising giant Emily’s List, which works to elect women who support abortion rights, has said it will spend tens of millions of dollars to defend and promote Ms. Harris this year.
The group sees her success as a key extension of its mission to elevate more Democratic women to public office. The organization will be joined by other groups, including the National Women’s Law Center, that are preparing to act like campaign watchdogs, ready to denounce sexist and racist attacks against Ms. Harris.
Polling conducted by Emily’s List last year found that Ms. Harris had high favorability ratings among key portions of the Democratic coalition, including Black women, younger voters and college graduates. Still, she remained fairly unknown to many.
About a third of Democratic and independent voters, the group’s polling found, didn’t know her personal story, her background as California’s attorney general and junior senator, or what she had done as vice president.
Senator Laphonza Butler of California, who served as the head of Emily’s List before Mr. Newsom appointed her to fill the seat vacated when Senator Dianne Feinstein died last year, said that the frantic nature of the 2020 general election, which was dominated by the pandemic, had provided limited opportunities for Ms. Harris to form bonds with voters nationally.
“She still needs to introduce herself to the country,” Ms. Butler said. “People just don’t know about her because she didn’t get the opportunity to tell her story.”
Most immediately, though, Ms. Harris and the Biden team are focused on delivering a big winning margin in South Carolina.
Local Democrats have urged supporters, who are free to choose which party’s primary they vote in, to cast ballots in the Democratic race and not wait for the Republican contest later this month. Some may be considering strategically backing Nikki Haley, a former South Carolina governor, in her long-shot battle against former President Donald J. Trump.
Clay Middleton, a veteran Democratic operative and a senior adviser for Mr. Biden’s team in the state, said the campaign had not told him its target for voter turnout.
He did say the campaign’s strategy of directing surrogates like Mr. Newsom and Mr. Landrieu to out-of-the-way rural towns was an effort to increase turnout in counties that often underperform in the state’s elections.
“Those counties rarely get high-level surrogates,” Mr. Middleton said. “These surrogates have spent time there, connecting with people.”
Even as the Biden campaign has studiously avoided making predictions about turnout on Saturday, Mr. Clyburn on Friday set the benchmark for success at between 150,000 to 200,000 votes, with the president receiving 70 to 75 percent of them.
“Seventy percent would be a success to me,” he said in an interview.
In 2016, when Hillary Clinton defeated Senator Bernie Sanders of Vermont, just over 371,000 people voted. In 2020, with no competitive Republican primary but 12 Democrats on the ballot in a race that was still up for grabs, about 537,000 people voted. South Carolina did not hold a primary in 2012, when President Barack Obama sought re-election and no Democrat filed to run against him in the state.
J.A. Moore, a Democratic state representative in South Carolina who was among the first officials in the state to endorse Ms. Harris’s 2020 presidential campaign, said her frequent visits as vice president had served as a “testing ground” to build relationships with parts of the party’s base — Black voters, young people and women — who were critical to Mr. Biden’s winning general-election coalition in 2020.
“She’s been here building real, connected relationships, specifically in the Black community, but also with women and young people as well,” Mr. Moore said. “Just her showing up to places goes a long way.”
Lisa Lerer contributed reporting.