CHARLESTON, South Carolina — Former Vice President Joe Biden leads the Democratic pack by more than 20 points in this crucial early primary state, but locals say he shouldn’t get complacent.

Democratic primary voters here can be unpredictable, and polling has obscured major swings in the past. In 2008, Barack Obama rode momentum from a key victory in Iowa to defeat Hillary Clinton in the state, even though she started with a double-digit lead early on in the race. But as Biden’s campaign points out, Clinton had a strong edge in 2016 — and kept it, winning handily.

In interviews with dozens of voters, Democratic state officials, and political strategists, most agreed: Biden shouldn’t assume he’s got this wrapped up, and candidates picking up in the polls, like Sen. Elizabeth Warren, shouldn’t count themselves out. Other challengers, including Sens. Cory Booker and Kamala Harris, still have the potential to expand their gains in-state as well, officials added.

“Right now, it’s anybody’s to win,” Spartanburg County Democratic Party Chair Angela Geter, who has yet to endorse a candidate, tells Vox. “Nobody has it in the bag. Everybody needs to put in the work.”

“I’m actually surprised at how many people are paying attention to these polls, given what happened in 2008,” says Anton Gunn, Obama’s 2008 South Carolina political director, who is not affiliated with any current campaign. Biden’s team, meanwhile, says they’re not taking his lead in the state for granted.

South Carolina poses a central test for both Biden and Warren’s campaigns. It’s the fourth state to vote in 2020, after Iowa, New Hampshire, and Nevada, and it’s one of the most diverse.

For Biden, it’s a question of whether his legacy will be enough to sustain a make-or-break win there. For Warren, it’s a question of just how much support she can build up among African American voters, one of the Democratic Party’s most important constituencies.

Biden currently maintains a strong lead, but it’s narrowed some: While he came in at 46 percent in a Post and Courier poll in May, that’s since dipped to 36 percent in an August survey from the paper. In those same polls, Warren’s support shot up from 8 percent to 17 percent.

Warren’s now second in the state, ahead of Sanders and Harris, according to RealClearPolitics’s polling average. She’s also picked up momentum in both Iowa and New Hampshire, where she’s effectively tied with Biden.

Many voters in the Palmetto State are still making up their minds, a factor that adds to the uncertainty. Based on an October survey from Winthrop University, over 50 percent of South Carolina voters currently say they could still switch candidates.

“I think that people are firmly Joe Biden right now, but I think that that can change,” CeCe Grant, 53, a Columbia resident who works in environmental conservation, tells Vox. “I don’t think this race is locked at all.”

Biden’s the clear frontrunner in South Carolina

Of the early states, South Carolina holds particular significance: The Democratic electorate is more than 60 percent African American and the outcome of this race is seen as a bellwether for how much backing candidates are able to rally from voters of color.

No Democratic candidate has won the nomination without South Carolina since 2004, when then North Carolina Sen. John Edwards beat out former Massachusetts Sen. John Kerry.

For both Biden and Warren, this February 29 primary will send a decisive message going into Super Tuesday: Either they’re able to secure a strong degree of African American support, or they’re simply not resonating with a crucial constituency of the Democratic base.

Currently, Biden is in a far stronger position with black voters, especially older African Americans, who associate him fondly with Obama.

“The black folks support Biden, next to Jesus right now, that’s where he is,” Dot Scott, head of Charleston’s NAACP chapter, told Vox. “You cannot underestimate how African Americans felt that he was willing and accepting of serving under the first black president. That’s huge. That’s a level of respect being shown to black people.”

Biden’s visits to the state over the years have also helped many Democrats feel like they know him.

Several people I spoke with pointed to his numerous trips to South Carolina, including the eulogy he gave at former Sen. Fritz Hollings’s funeral even before he began his run for president. According to his campaign, he’s also attended several other events in recent years, including a 2014 commencement address at the University of South Carolina and the 2017 unveiling of a Hollings commemorative statue in Charleston.

“You know Joe Biden’s record. This is not his first time getting on the train,” says Democratic strategist Antjuan Seawright. “You’re starting to see the dividends of his long term investments in the state.”

Biden supporters also see him as the “seasoned” pick, who’s best poised to not only beat President Donald Trump, but help the country find its footing after he takes office. He’s “Mr. Reliable,” says Seawright.

And while aspects of Biden’s record have prompted pushback from some Democrats, his fans aren’t shaken by them. Concerns over his handling of Anita Hill’s testimony during the Clarence Thomas hearings, his vote for the Iraq War, and his work on the 1994 crime bill, are outweighed by the stability his leadership could represent, they say.

“That doesn’t faze me,” said Anthony Cunningham, 47, a city council member in Fountain Inn, South Carolina, when asked about Biden’s political missteps.

“It doesn’t really hurt him because people feel like they have that affection for him because he was Uncle Joe,” Spartanburg’s Geter said. “He certainly has his baggage, but I don’t know that that baggage is substantial enough for people to say, ‘Well, I’m not going to vote for him.’”

Biden also has another thing working in his favor: The electability argument he’s making is resonating with some voters, many who see him as the best option to take out the president.

“At the end of the day, what matters for me is whether or not they can beat Trump,” Lawrence Davis, 51, an adjunct professor who lives in Sumter County, South Carolina, told Vox. “Based on ... who can beat Trump, my candidate is Joe Biden, Biden all the way.” Davis noted that he hoped the country would one day elect a woman for president, but he wasn’t sure it would in 2020.

As has been seen nationally, a focus on retaking the White House is central to many voters’ decision.

“South Carolinians are very pragmatic voters. While our ground operation was helpful to inspiring voters to vote for the ‘change candidate’ [in 2008], right now South Carolinians are laser-focused on the change being to get Trump out of office,” said Alaina Beverly, a deputy political director in the state on Obama’s 2008 campaign. “That is always going to yield in favor of Joe Biden winning South Carolina.”

Biden’s path to the nomination increasingly appears to run straight through the southern state. Of the four early states, South Carolina is the only one where he maintains a substantial lead on Warren.

“If Biden loses South Carolina, it probably means his edge with [African American voters] has dissipated, meaning that the person who caused that support to dissipate likely would be in the driver’s seat,” says University of Virginia’s Kyle Kondik.

Elizabeth Warren is making inroads

Given the parallels between this cycle and the 2008 primary, some Democrats wonder whether Warren — or others — could pull off what Obama did and overtake Biden, the establishment candidate. At this point in the race in 2008, Obama was lagging behind Hillary Clinton in the polls, though he ultimately defeated her by a 55-27 percent margin.

“It has that same feel it had in ’08,” South Carolina state Rep. Jerry Govan, the head of the state’s legislative black caucus, told Vox. “I think that anything can still happen.”

According to South Carolina state politics experts, Warren is particularly making inroads among African American women, a crucial contingency she’s beginning to impress with her expansive roster of plans and focus on issues like maternal mortality and reparations.

“[I like] the fact that she’s a woman candidate, and she’s got an answer,” Lisa Ivy, 51, a Warren supporter and member of the Sumter County Democrats, said. “I like the fire that she gives when she talks.”

Winning support from African American women is integral to performing well in the state, where they make up a plurality of the Democratic electorate. At a national level, African American women also vote at the highest rates and are consistently the most dedicated Democratic supporters.

“She’s that history teacher you’d want to have because she’ll give everything to you at face value,” adds Desiree Haywood, 28, the secretary for the South Carolina Democratic Black Caucus. “She’ll tell you everything you need to know for the test.”

Since this summer, Warren has managed to increase her share of national support among African American voters. As Politico’s Maya King pointed out, Warren’s backing among black voters rose by 9 percentage points between Quinnipiac polls in August and September. According to the September Quinnipiac survey, she now has 19 percent of African American voters’ support, compared to Biden’s 40 percent.

“When Elizabeth Warren started the race, she was in single digits with African American voters,” said South Carolina state Rep. Kambrell Garvin, 28, a Warren supporter. “She’s a white female from Massachusetts — of course she’s from Oklahoma [originally], but doesn’t have any roots in South Carolina, or a lot of these Deep South communities. I think it’s a matter of folks getting to know her, getting to know her message.”

Early national surveys showed Warren lagging on this front, a dynamic that officials chalked up to name recognition and her position as an “unknown.” Several voters also raised the “electability” question, including one who emphasized that her handling of the controversy around her claims of Native American heritage and DNA test prompted concern about whether she could effectively confront Trump.

South Carolina Democrats say Warren needs to continue refining her message and dialing up outreach toward African American voters if she wants to keep on growing this backing. Among the 2020 Democrats, Warren’s visits to the state have been sparser than several of the other leading contenders. She currently ranks 14th when it comes to visits she’s paid the state, behind Tom Steyer and Sen. Michael Bennet, according to a tracker from the Post and Courier.

Warren’s campaign says she has nine offices in the state and plans to open up even more in the coming months. They add that the campaign is investing in “people and infrastructure,” and focused on holding events, like a recent town hall in Orangeburg centering on student debt that “connect her own story with local issues.”

“Trust in the candidate matters, especially for African American voters. You aren’t going to pick somebody you don’t recognize. She’s got a lot of room she has to make up among African Americans,” says Scott Huffmon, executive director of the Winthrop University poll.

In addition to increasing her own presence in the state, veterans of the Obama 2008 campaign say that Warren needs to recruit and promote more surrogates.

“Are there are any African American leaders in Massachusetts who are campaigning on behalf of Elizabeth Warren?” Gunn asked. “Who’s vouching for her that’s black and respected? If she doesn’t have any surrogates who are campaigning on her behalf, it’s going to be hard to get that black support and make that connection.”

Both Gunn and Beverly credited the Warren campaign with a strong grassroots operation, but argued that additional events, including those in smaller settings, like people’s homes, would be important.

“The importance of retail politics cannot be overstated for South Carolinians,” Beverly added. “They want to be asked for their vote.”

There’s a generational split in how African American voters are leaning

While Biden’s national poll numbers with African American voters look very strong, the top lines obscure a key differentiator: age.

According to an October Morning Consult poll, Biden has 41 percent support from African American voters overall. When this data is broken out by age, however, Biden has just 25 percent support among African American voters ages 18-29, and 32 percent among African American voters ages 30-44, compared to 48 percent among African American voters 45-54, 53 percent among African American voters 55-64 and 56 percent among African American voters over 65.

“I think there’s a generational gap between younger African Americans and older African Americans,” Garvin said. “Younger African Americans like Joe Biden, but a lot of us aren’t supportive of Joe Biden, because we want a change in policies. We aren’t looking to tinker around the edges.”

Though Joe Biden is by far performing best with older African American voters, Bernie Sanders wins a larger share of those 18-29 and 30-44, nationally. Warren, Harris, and South Bend, Indiana, Mayor Pete Buttigieg continue to trail both Biden and Sanders in these age groups, though Warren has seen growth among them between June and October.

Younger voters I spoke with broadly expressed a deep respect for Biden, but argued that they were interested in representation that pushed for more ambitious change.

College students Andrea Kimpson, 17, and Hayle Turner, 18, are fans of Harris and Buttigieg, and they wondered if Biden would be “adaptable to the needs of the new electorate.”

“This is my first election, and I want it to reflect my values and not those of my parents or grandparents,” Kimpson said.

“They are defending him so hard,” Haywood told Vox, about the commitment many voters have to Biden. “Older black people are actually really conservative; they just paint over things.”

Younger voters are poised to play a major role in the 2020 primary, if they turn out in strong numbers. In 2018, turnout among younger voters spiked nationally jumping from 20 percent in 2014 to 36 percent.

Were a surge like this to play out in 2020, it could wind up benefitting candidates like Sanders and Warren.

South Carolina is a proving ground before Super Tuesday

Of the four states that hold primaries or caucuses in February, before a deluge of delegates is up for grabs in 13 states on Super Tuesday, South Carolina is last.

Because of their placement in the primary schedule, the outcomes of the contests in Iowa and New Hampshire could have an impact on South Carolina, giving whoever wins those states a boost of momentum. Obama’s win in Iowa, for example, was seen as central to bolstering his victory in South Carolina, because it showed voters that a predominately white electorate would support an African American man for the presidency.

“When Barack Obama won Iowa, that helped us close the deal with white voters. When white voters in South Carolina saw that ... that’s what helped us close the gap,” said Gunn, Obama’s 2008 South Carolina political director.

It’s possible that a similar dynamic could emerge again this time around, with an Iowa victory playing in Warren’s favor.

The results in South Carolina — meanwhile — will set the tone for both Biden and Warren’s campaigns for the rest of the primary.

“No Democratic nominee since Michael Dukakis has won the nomination without also winning nationally among African American voters,” University of South Carolina’s David Darmofal said. “If Sen. Warren finishes a distant second behind Biden, or behind other candidates in South Carolina, this would suggest a potentially serious limitation in her candidacy.”

Similarly, if Biden loses the state, it could deal a major — and potentially fatal — blow to his campaign.