Black voters effectively delivered Hillary Clinton the Democratic presidential nomination in 2016. She and Sen. Bernie Sanders ran about evenly among white voters, but black voters overwhelmingly backed Clinton. So did the Democratic establishment.

That team-up — black voters and the more establishment candidate — is not unusual.

We don’t have detailed exit polls of Democratic primaries for most other offices, but according to pre-election polls and precinct results in a number of high-profile House and gubernatorial primaries since 2016, black voters have tended to back the candidate from the party’s establishment wing over a more liberal alternative. And at least for now, we’re seeing the same pattern in the 2020 Democratic presidential race: Sens. Elizabeth Warren and Sanders are fairly competitive with Joe Biden among white Democrats, but trail the former vice president substantially among black Democrats.

Why, though? After all, African Americans have dramatically less income and wealth than white Americans, so messages of “big, structural change” (Warren) or a “political revolution” (Sanders) should, in theory, be particularly appealing. Because a higher percentage of black Americans than white Americans don’t have health insurance, a program like Medicare for All, for example, would disproportionately benefit black people.

So what gives? I’m going to offer some potential answers to that question, but let’s first get a couple caveats and complications out of the way.

First, it’s hard to come up with a definitive explanation for the establishment-black voter alliance because the “establishment” is a fuzzy concept. Exactly which candidate is a center-left, establishment Democrat and which is anti-establishment or “the liberal alternative” is all a bit subjective.

Second — and this is important — black Democrats are not a monolith and are divided in some of the same ways white Democrats are divided. Young black voters are less supportive of Biden (and were less supportive of Clinton in 2016) compared to older black voters. Similarly, black voters without college degrees are more supportive of Biden than those with degrees.

That said, blacks of all demographics are more supportive of Biden than their white counterparts, according to Morning Consult polling data. Young black voters are more supportive of Biden (and were more supportive of Clinton) than young white voters. Older black voters were more supportive of Clinton than older white ones in 2016 and now are strongly behind Biden. Black college graduates are more supportive of Biden than white college graduates. Nuances aside, the weakness of the liberal wing of the Democratic Party with black voters is a well-known phenomenon that people in the Warren and Sanders camps and anti-establishment liberal activist groups are openly grappling with.

So here are a few explanations for why black voters have tended to side with the establishment wing of the Democratic Party. I have tried to order these explanations from strongest to weakest (in my view, at least):

1. Establishment candidates typically have existing ties to the black community

This will sound tautological, but an establishment candidate is … well … established. A candidate who is part of the establishment wing of the Democratic Party likely has fairly strong ties to major constituencies in the party, such as labor unions, women’s rights groups and, of course, black leaders and voters. So when black voters backed Gov. Andrew Cuomo over Cynthia Nixon in New York’s Democratic gubernatorial primary last year, or Andy Beshear over Adam Edelen in Kentucky’s Democratic gubernatorial primary earlier this year, that was not shocking. Not only did Beshear and Cuomo spend years developing their own ties with the black communities in their states, but their fathers did, too. (Steve Beshear was governor of Kentucky, Mario Cuomo the governor of New York.)

Clinton in 2016 and Biden in 2020 similarly entered the primaries with longstanding ties to black voters. It’s worth considering if the story here is not that establishment candidates are smarter in appealing and connecting with black voters during the campaign, compared to anti-establishment candidates. Maybe it’s that the establishment candidate in a race is likely to be the person who enters the campaign with the strongest support among black voters.

2. Black voters are pragmatic

White Democrats are significantly more likely than black Democrats to describe themselves as liberal. Perhaps that’s the simple explanation for why most black voters eschew more liberal candidates. But scholars of black voters argue that the liberal-moderate-conservative framework does not apply well to predicting the actual policy positions and voting behavior of black Americans.

In other words, it’s not clear that “moderate” black Democrats are moderate in the way that the word is most often invoked in white-dominated, elite settings, such as cable news and Twitter. They’re not demanding David Brooks-style centrism on economic and cultural policy. If, for instance, Biden endorsed Medicare for All and the elimination of most private insurance plans — the position of Sanders and Warren — I think it’s likely that black voters who like Biden would begin to feel more favorable about Medicare for All rather than breaking with Biden to find an anti-Medicare-for All candidate. Similarly, if Biden were out of the race, I’m skeptical that much of his support among black voters would go to Mayor Pete Buttigieg or Sen. Amy Klobuchar who are also positioning themselves as centrists on policy issues.

“The fact that blacks describe themselves as moderate or conservative on these measures is virtually meaningless, and results mostly from the fact that these ideological labels carry such little currency among black voters,” Hakeem Jefferson, a political scientist at Stanford University who studies black political attitudes, told me.

Instead, in interviews with black Democrats in 2016 and 2020, I’ve seen more pragmatism than moderation. In 2016, black primary voters were very fearful of Trump getting elected and felt Clinton was the best person to face him in a general election. They were skeptical that the broader electorate would like Sanders’s farther-reaching ideas, and even more doubtful Sanders could execute them if elected. During the 2020 cycle, black voters have regularly told reporters that they like Sen. Kamala Harris and other Democratic candidates but view Biden as the person most likely to defeat Trump.

Why would black Democrats be more pragmatic than white Democratic voters? In interviews, black voters often suggest they have a lot to lose if a Republican takes office. They don’t necessarily say this explicitly, but the implication is that they have more to lose than white voters, making them more risk-averse. That’s at least partially true. A higher percentage of black Americans (compared to white Americans) use government programs like Medicaid, for example, so cuts to those programs by Republicans are more likely to affect blacks than whites.

“On doorsteps in South Carolina, black voters sensibly asked me why I thought Bernie Sanders could accomplish more than Obama, whom the Republicans had done everything they could to stop,” wrote Ted Fertik, in a study of the Vermont senator’s campaign.

“They saw no reason to believe that Sanders would be more effective, and given the fulminating racism of so many leading Republicans, they sensibly felt that the costs of a Republican presidency would fall more heavily on them,” he added. “They were therefore not inclined to take a risk on Bernie Sanders … even when they agreed with his proposals.”

3. Black leaders are part of the establishment and support its candidates

This is a slightly different point than No. 1, above. It’s not just that Sanders in 2016 and Warren in 2020 entered those races with weaker connections to black leaders than Clinton or Biden. During the primary process, black leaders weighed in — on the side of the establishment candidate.

In February 2016, fairly early in the primary season, the Congressional Black Caucus’s PAC formally endorsed Clinton. Eight black caucus members have endorsed Biden this year. None are behind Warren or Sanders. You might say that politicians just like to endorse front-runners, so they can be on the side of the winner. Not quite. Ten black caucus members have backed Harris, another candidate whose politics are best described as center-left establishment. (More on her in a bit.) And Biden and Harris are also getting the vast majority of endorsements from other high-profile black figures, such as state representatives and prominent mayors.

Why are elected black officials more likely to side with establishment candidates? Many of these candidates have long courted black community leaders, including elected officials, as I mentioned in No. 1. But I also think it’s the case that many black Democratic elites spent much of the last several decades courting the establishment, and are thus tied to it. You see this on Capitol Hill, where black House members are among the strongest defenders of Speaker Nancy Pelosi in her internal battles with Rep. Alexandria Ocasio Cortez and the progressive wing of the House. Black elites also express the same pragmatism that black voters do and are wary of pushing forward candidates they view as unable to win a general election.

It’s not clear that black voters follow high-profile endorsers. That said, the lack of high-profile black support for Sanders, Warren and other anti-establishment Democrats creates a self-reinforcing problem. They don’t have much support among black voters or black elites, so the press covers their lack of black support. A candidate defined by the press as lacking black support is going to have a hard time getting black voters to support her or black elites to endorse her.

4. The liberal wing of the Democratic Party appeals to the well-educated more than other groups, and the vast majority of black Democrats don’t have college degrees

Education has become an increasingly powerful predictor of voting behavior in U.S. politics in recent years. That’s proving true in 2020 as well. Warren, in particular, has significantly more support among Democrats with college degrees than those without them. But if education is a dividing line, it’s likely to divide white and black Democrats. Only about 24 percent of black Democrats have college degrees, compared to about 42 percent of white Democrats, according to Gallup data.

In other words, the alliance between black voters and establishment candidates may be partly about education, not race. Perhaps Warren’s limited support among black Americans is simply indicative of her broader challenge with people without college degrees.

We don’t have great data about how Sanders or other liberal Democrats did among black college graduates compared to non-college educated black voters, so I’m reluctant to emphasize this point too much. But there is a lot of evidence that the activist left wing of the Democratic Party is more educated than the rest of the party and perhaps is not connecting with voters — both black and non-black — who don’t have degrees.

5. The left wing isn’t running enough black candidates

There is some evidence that African Americans are more likely to turn out to vote if there is a black candidate. (These studies are generally of general elections of congressional races, so they’re not perfectly analogous to a presidential primary.) In recent Democratic primaries, the candidate who is well-liked by the white liberal activist wing of the Democratic Party has struggled with black voters (Bill Bradley in 2000, Howard Dean in 2004, Sanders in 2016, Sanders and Warren in 2020.) The exceptions were two black candidates: Jesse Jackson in 1988 and Barack Obama in 2008.

So it would probably be helpful if the liberal wing of the Democratic Party was running more black candidates. It’s not that the liberal bloc of the party has no prominent black voices. Rep. Ayanna Pressley of Massachusetts is a part of the Ocasio-Cortez bloc on Capitol Hill. Andrew Gillum ran to the left and defeated a more establishment candidate in last year’s Democratic primary for governor in Florida, with black voters playing a key role in his victory.

But aspiring black politicians often need to downplay their liberalism to advance in elected office so that they can seem “electable” in a general election. This probably rules out some black candidates — Sens. Cory Booker and Harris, potentially — from becoming “liberal alternatives.” You might say that’s a problem for Booker and Harris, who are trailing Warren and Sanders in most polls. But it’s a problem for the anti-establishment wing of the Democratic Party, too. If the anti-establishment wing of the party were backing a black candidate in 2020, that person would likely present a stronger challenge to Biden, because he or she could more easily cut into his advantage among black voters.

We could come up with some other explanations, but I think those are the strongest. And this analysis points to a blueprint for the left wing of the Democratic Party if it wants to win more black votes:

Align with black candidates or non-black candidates with strong ties to black voters and leaders Aggressively court black leaders for endorsements Directly address black voters’ concerns that more liberal candidates have a greater chance of losing races to Republicans And target black voters under 45 and those with college degrees, who might be less inclined to vote for establishment candidates.

So could that approach work for Sanders and Warren against Biden? Maybe. You could imagine Warren in particular getting endorsements from younger liberal black figures like Gillum or Pressley (particularly if Warren wins one of the early primary states and Harris finishes far behind and is no longer viable). And maybe those endorsements and Warren’s campaigning then lead her to become the candidate of black voters under 45 and those with college degrees, even if Biden still gets most votes from older and less educated black voters.

Remember, Sanders or Warren don’t necessarily have to win the black vote to become the Democratic nominee — they just can’t lose it by 60 percentage points, as Sanders did in 2016. (Biden is getting between 40 and 50 percent of the black vote in most polls now, so nowhere near Clinton 2016 levels. But Clinton was in a two-candidate field, and I would expect Biden’s support among black voters to go up as this gigantic field shrinks.)

But even if Sanders or Warren gets more support among black voters in 2020 than the Vermont senator did in 2016, I tend to think Biden will remain fairly popular with black voters overall — because of his ties to Obama and other black leaders and the perception that he can defeat Trump. So there is a very real possibility that black voters will play the same role in the 2020 presidential primary that they have played in Democratic politics over much of the last four years: blocking the path of the liberal left as it attempts to dethrone the party’s establishment.