Elizabeth Warren campaigning in an African-American church in South Carolina. Photo: Meg Kinnard/AP/Shutterstock

One of the major story lines of the 2020 Democratic presidential-nomination contest is the not-very-successful-so-far efforts of African-American candidates Kamala Harris and Cory Booker to pry black voters away from their strong support for Barack Obama’s vice-president, Joe Biden. But there’s a subplot, too, that may become vitally important if Harris and Booker never achieve top-tier status: Are there white candidates who can challenge Biden in this demographic? That could matter a great deal when the contest turns to the South — beginning with South Carolina on February 29 — where in several states African-Americans are a majority of the Democratic-primary electorate. It certainly did in 2016, when Bernie Sanders’s poor performance against Hillary Clinton among black voters hugely contributed to her series of overwhelming wins across the South and in other states with large African-American populations.

Polls this year indicate that, despite having a much smaller piece of the pie (unsurprising given the huge Democratic field as compared to the one-on-one competition of 2016), Sanders is doing relatively well among African-Americans. In fact, a recent national Fox poll showed Sanders running better among black voters (18 percent) than white voters (15 percent), presumably due to more effective campaigning and his appeal to young voters, who skew nonwhite.

Apart from Sanders, however, other white candidates are struggling to show the biracial support that is so essential to winning the South, most notably Pete Buttigieg (whose black support in the Fox poll was too slight to register) and Elizabeth Warren (at 8 percent among black voters, compared to 25 percent among white voters). For the surging Warren, this is becoming an increasingly serious obstacle to her emergence as a potential progressive challenger to Biden, and to the “unity candidate” mantle she would need as the nominee.

It’s not surprising that Warren isn’t that strong among black voters. She is, for all her “populism,” a former Harvard professor representing a very white state. Her following is disproportionately college-educated, higher income, and self-consciously progressive — people who are sometimes called “wine track” voters (despite her professed affection for beer). Black Democrats are significantly less likely to self-identify as “progressives” than white Democrats.

Indeed, the one-dimensional nature of Warren’s support is holding her back in places like South Carolina, where, according to a new Post and Courier poll, she is leading Biden among white voters but running a weak fourth among black voters, leaving her a bit behind Sanders overall.

However, like Sanders, Warren has been careful to develop policy proposals specifically designed to address the concerns of African-Americans, including a criminal-justice-reform agenda, a plan to boost black entrepreneurship, and an initiative to reduce maternal mortality among black women. And her retail politicking, as the Washington Post reported after a weekend of competitive Democratic campaigning in South Carolina, is showing some serious chops:

[I]n South Carolina, Warren and her team appeared to be navigating the racial landscape more astutely than Sanders. Among the speakers warming up a crowd for her Saturday evening in Aiken, S.C., was Lessie Price, a local black leader and the first vice chair of the state’s Democratic Party.

Warren’s message, Price said, speaks to African Americans. “Often­times, it’s getting that message out over and over and over, and someone starts hearing it,” said Price, who is staying neutral in the primary.

Speaking to a black church is particularly sensitive, she said. “The church in the past has been a rallying point to really see what a candidate is truly about,” Price said. “You have to change your message in that setting….”

This is Warren at a black Methodist church in Columbia, South Carolina’s capital, on Sunday:

Rather than her usual firebrand stemwinder, she talked about her hardscrabble biography, including an anecdote about how she once struggled to control an unruly fifth-grade Sunday school class.

“They cut each others’ hair during the art project,” Warren said, adding touch of Southern cadence to her voice. “Oh! They spilled things on each others’ clothes. It was wild. The boys climbed out the window.”

Warren said she used the story of Noah and the ark to capture the imagination of the class. “I started asking the kids about duty, about what we owe to each other,” Warren said. Eventually, she said, a student landed on the answer, saying, “We owe each other that everybody gets a turn,” a comment that fits into her rationale for running for president.

Meanwhile, Bernie Sanders skipped services at another black church in the area, and the fact that he drew a crowd of white followers to his speech while black churchgoers enjoyed their post-worship fellowship did not go over very well:

Although black churchgoers ate nearby, Sanders delivered his remarks to a group of mostly white voters who came just to see him. Several Sanders supporters insisted they shouldn’t have to pay for the luncheon since they had come only to hear the candidate.

The overall effect — a crowd of largely white outsiders descending on a weekly lunch for a black church — alienated several churchgoers.

That may have represented just bad luck or bad staff work, though it’s interesting that something very similar happened to Bernie at the same church in 2016, as the New York Times reported:

Sanders walked into the dining room of the revered and predominantly black Brookland Baptist Church here. Instead of flocking to him, as supporters do at his large college rallies, many of the church’s 780 members present looked up for a moment, then quietly went back to eating their Sunday feast — unmoved as Mr. Sanders, the senator from Vermont, tried to work the room….

“We have, in America today, a broken criminal justice system,” Mr. Sanders said at the microphone, pausing briefly after this line from his stump speech, which is usually met with applause. Here it garnered very little, and the line for the food kept moving. Brookland Baptist Church proved a tough crowd.

This isn’t the easiest venue for a secular Jew. In 2004, Joe Lieberman was in a black church in South Carolina, where the minister went around the sanctuary asking parishioners if they loved Jesus. He got to the candidate and asked: “Senator Lieberman, do you love Jesus?” And Lieberman just smiled. What else could he do?

But whatever he lacks in style points, Sanders appears to have made up for it with substance, or perhaps he’s simply stronger among younger black voters who are less likely to be in church on Sundays. Warren appears to have the potential to catch up, but both candidates really need to broaden their appeal.