In the 2008 presidential primary, Democrats chose between a black candidate and a white candidate. Yes, that described the race of the two leading rivals, but also their constituencies: Barack Obama won 82 percent of African-American votes, while Hillary Clinton won most whites, including 62 percent of whites without a college degree.

In 2016, once again, throughout most of the primary campaign, there’s been a black candidate and a white candidate—when it comes to their supporters, anyway. Only this time, it’s Clinton who’s racking up the black vote, and Vermont Senator Bernie Sanders who has been leading among whites, especially the white working class, while losing roughly 4–1 among the African-American voters who are the bedrock of the Democratic Party. In states like Iowa, New Hampshire, Oklahoma, and Michigan, Sanders beat Clinton among whites without a college degree. And this time, it’s Sanders who is making the political case for the importance of winning back white voters, particularly working-class whites, to the Democratic Party, as Clinton did eight years ago.

And as I did, too. I began the 2008 primary season thinking Clinton’s support from white working-class voters was a sign that Democrats could make inroads there, and win back so-called Reagan Democrats to the party of FDR. I ended the 2008 contests in despair, seeing Clinton’s attempt to win white votes devolve into her using her support from “hard-working Americans, white Americans” against Obama in a way that rightly repelled African Americans, and me too. By 2012, I no longer saw a way for Democrats to win back vast numbers of whites that didn’t involve somehow negating the power, influence, and interests of African Americans, who have become the most reliable Democratic voters. Negating that influence would be politically stupid as well as morally wrong.

Bernie Sanders is going to eventually have to take in that reality. As he saw his hopes in the South crushed by black voters, who went four or even five to one for Clinton, his campaign made noises—increasingly unpleasant noises, to the ears of some black voters—about how that might change as the race moved from south to north. Campaign manager Jeff Weaver insulted black voters by dismissing Clinton as a “regional” candidate only popular in the South. Jane Sanders, the candidate’s wife and best surrogate, even suggested that the “Obama coalition” was a shopworn, 2008 phenomenon; a new “Sanders coalition” might make it possible for her husband to win with the support of fewer African Americans and more working-class whites.

And Sanders himself staked his chances on the perspicacity of Northern black voters. “I think you’re going to see us doing—and I think the polls indicated it—much better within the African-American community outside of the Deep South,” Sanders said after losing South Carolina. “You’re going to see us much better in New York State, where I think we have a shot to win, in California and in Michigan.”

Well, he did do better in Michigan. He won the primary, and he got 28 percent of the African-American vote, as opposed to 5 to 25 percent in other states. That was widely hailed as an improvement; it really shouldn’t have been. In Ohio, he got 28 percent of the black vote, according to CNN exit polls; in Illinois, where he hoped to do well because of African-American anger at Chicago Mayor Rahm Emanuel, who had endorsed Clinton, he won 29 percent. In North Carolina and Florida, he did almost as poorly as he did in South Carolina. He had his best night with black voters in Missouri (go figure), where he won 32 percent. And even among black millennials, Sanders trailed Clinton in the March 15 primaries, winning just 36 percent.

If doing “better” with African Americans wins meaning three in 10 rather than one in 10, the Sanders coalition is in real trouble. No Democrat can win the party’s nomination with only a third of African-American voters. And no Democrat should.

Clinton’s big wins last week almost certainly guarantee her the nomination. Sanders promises to fight on, however, and he deserves to. He’s raising crucial issues, and he’s already helped pull Clinton to the left. But if he wants his effort to yield lasting organizing victories for the left, he better study the lessons of the first half of his campaign. One thing should already be clear: No multiracial, left-wing coalition can be successfully built out from a white base. Let’s stop trying.

* * *

I once believed that a full-throated populist strategy could bring large numbers of white, working-class voters back to the Democratic Party, and that such a focus would improve American politics and the party. Why did I change my mind? Partly because I saw how divisive it was when Clinton (sort of) tried it. I ultimately wound up writing a whole book about it—What’s the Matter With White People?—though I didn’t think that’s what I was doing when I set out to write.

Back in 2008, I was a Clinton defender who eventually became a Clinton supporter, because I thought the media, and much of the left, had irrationally anointed Obama the progressive candidate, even though many of Clinton’s domestic policies were to his left. Her healthcare plan covered everyone; Obama’s left at least 15 million unprotected. She railed against growing evidence of bad banking behavior, even before the crash, coming out for a foreclosure moratorium, for the regulation of derivatives and for closing the “carried interest” loophole that privileged investment banking. Obama supported none of these proposals and, even running against the New York senator, he became the preferred candidate of Wall Street.

The fact that she had much more white working-class support than Obama in 2008 only “proved” to me what I’d always believed—that those voters might return to the party of FDR if someone ran a sufficiently populist campaign. That someone seemed to be Hillary Clinton. In her moral and political defense, she also had the votes of Latinos and women (which Sanders does not this cycle). I knew some of Clinton’s white, working-class support surely had to do with Obama’s race, but it made me uncomfortable when his supporters suggested that was all there was to it. Eight years later, I’ve got to admit that racism drove some of Clinton’s supporters much more than I wanted to believe.

Now it’s Bernie Sanders who is the “white” candidate, supported by many of those same working-class voters. The extent to which they’ve abandoned Clinton this time around is surprising to me. I think there are a few explanations for this shift, the first of which is that Sanders is genuinely appealing to working-class white voters—they like fighters and outsiders, and they respond to a strong populist pitch. But we also have to contend with the extent to which Clinton may have been damaged by her close association with our first black president, serving as his secretary of state and eventually forging a close alliance with him. This relationship solidified Clinton’s status as “the black candidate,” while at the same time burnishing her credentials as a member of the global elite—a combination that was unimaginable eight years ago. Coming out of the administration and joining the Clinton Foundation only cemented that elite status. Making speeches to Wall Street for a quarter-million a pop also cost her white working-class street cred—as it should.

We should also acknowledge the extent to which Sanders has won whites by crafting a class-based appeal that minimizes, and sometimes even diminishes, the role that racism plays in creating American social and economic inequality. He has done so for his whole political career. Sanders is in some ways uniquely suited to be the Democrats’ white, working-class standard-bearer, because a career in 98 percent white Vermont has kept him on the right side of some issues that hurt Democrats with that group. Over the years, moving out from his Burlington base, Sanders carefully crafted a coalition that includes both urban progressives and rural, gun-owning moderates. The votes and positions that put him to the right of most Democrats, on guns and immigration, play well with his overwhelmingly white base. He frankly defends his pro-gun votes as necessary to serve his rural, gun-owning constituency. Protecting his rural and lower-income white base also explains why he voted against the 2007 immigration bill. During the 2016 campaign, he has said he cast that vote because the bill would have created a caste of guest workers living in conditions akin to slavery. But at the time, he also told the race-baiting CNN pundit Lou Dobbs that pro-reform senators are “selling out American workers. In fact, they are selling out our entire country.” When Dobbs replied by ranting against “illegal aliens” and “the amnesty legislation’s socio-ethnocentric interest groups who really have very little regard for the traditions of this country, the values of this country,” Sanders didn’t correct him, or note that those “values” included xenophobia and racism.

Even his decision over the years to run as a socialist, or an Independent, and not as a Democrat, has helped Sanders with his white, working-class base, which a slew of research shows has come to see Democrats as the party of minorities. In other states, “socialist” might be an albatross of a label; in Vermont, the term “Democrat” may cost you votes. “I look at these things more from a class perspective,” he told Nate Cohn of The New York Times last year, after Cohn minimized Sanders’s chances to win the Democratic nomination. “I’m not a liberal. Never have been. I’m a progressive who mostly focuses on the working and middle class.” Many of his supporters “may not be liberal” and may not “agree with me on gay marriage,” he told Cohn, but “they want a fighter.” In Vermont, liberals “have not been [my] strongest supporters,” he noted; his support came from white working-class voters.

In 2012, Sanders ran unopposed in the Democratic primary, with the agreement of party leaders. But he refused to run on the party line that November, keeping an “I” next to his name on the general election ballot, even though he caucused with Senate Democrats. Watching his political calculation in this primary campaign, I’ve come to believe that was at least partly because he thought the label “Democrat” hurt his chances with working-class whites.

In 2016, all of these calculations have hurt him with the Democratic base.

* * *

After Obama’s first election, Sanders emerged as one of his sharpest critics, the only person in Congress to suggest that the president should face a primary from the left. I remember the conditions in late 2011 that gave rise to such a suggestion, the series of useless compromises with an intransigent GOP that culminated in the awful and thankfully unsuccessful “grand bargain.” I made enemies with my own criticism of the president back then.

But it was, in fact, Sanders’s call to primary Obama that forced me to reckon with the reality of the 21st-century Democratic base—the bedrock of which is African-American voters. Given the horrific racism faced by the first black president, they weren’t going to see him primaried just because some loud-mouthed, white progressives thought he handled that intransigence, driven in part by racism, less than optimally. At some point, I had to say to myself: Shut up and listen. I am not sure Bernie Sanders ever shut up and listened.

Hillary Clinton did, I believe. She listened to African-American friends and onetime supporters, who explained why her appeals to “hardworking Americans, white Americans” sounded like, and may actually have been, racist dog whistles. She went to work for Obama when he asked her to, as his loyal secretary of state. She mended fences with former allies like South Carolina Congressman James Clyburn, who fell out with the Clintons over their perception that he’d favored Obama, though he’d technically stayed neutral in the primary; this year, he set aside neutrality to back Clinton. She also learned to do electoral math the way the Obama team did it. Once she decided to run, she put aside thoughts of reassembling the (Bill) Clinton coalition, with its emphasis on winning back working-class whites by offering “toughness” on issues like welfare and crime. Her first speeches as a candidate dealt with voting rights, mass incarceration, and immigration reform, a sign that she knew she had to consolidate the Obama coalition before thinking about a new (Hillary) Clinton coalition.

None of this makes Clinton a better person than Sanders; it does make her a better student of Democratic Party politics, however. As I wrote last July, “Bernie Sanders does his own math,” and right now it’s not adding up. I don’t think it ever will.

At one time, I did my own math too—and in the end, it didn’t add up either. Back in 2008, my biggest problem with Obama was that I just didn’t believe he could win the presidency. When he won in 2008, and then again in 2012, that was it for me. I understood that the Democratic Party owes its occupancy of the White House to the Obama coalition: African Americans, Latinos, Asians, LGBT folks, and single women. Unfortunately, chasing white, working-class voters too often involves appeals that either passively neglect that coalition, or actively drive much of it away. Somehow Sanders doesn’t seem to see that. But that may well be because he is not, at heart, a Democrat.

“I am not a Democrat,” he once told The Progressive, “because the Democratic Party does not represent, and has not for many years, the interests of my constituency, which is primarily working families, middle-class people and low-income people.” Sanders needs to place the modifier “white” in front of all three groups, because the vast majority of African Americans, and most Latinos and Asians too, have come to believe the Democratic Party serves their interests, albeit imperfectly.

Sanders’s avid supporters haven’t helped him on this score. The sexism of the so-called BernieBro phenomenon has gotten most of the attention, but the racial cluelessness of the Bros has been pretty remarkable too. Many ooze condescension, dismissing Southern blacks as “low-information” voters. As the race moved north, many continued to lament that African Americans don’t seem to know what’s best for them as they vote for Clinton. The Sanders-supporting Progressive Democrats of America dismissed Clinton’s Southern victories as confined to “the Confederacy,” ignoring the fact that descendants of people enslaved by the Confederacy were the ones propelling big Clinton wins. To its credit, the group apologized. But Sanders himself continues to minimize Clinton’s Southern wins, because Democrats are “not going to win those states in the general election.” Media analyst Clay Shirky dubbed Sanders’s frequent racial flubs the “kettledrum effect,” an inverse dog whistle in which African Americans hear slights, insensitivities, and gaffes that voters who aren’t black may not.

If the Sanders movement is going to grow, it will only grow because more of his supporters begin to recognize their racial blind spots. I continue to hope that the populist policies championed by Sanders—on trade, on union rights, on Wall Street—will win white working-class voters back from the GOP. I hope that if, as seems almost certain, Clinton is the nominee, she will continue her leftward shift that we’ve seen during the primaries, and learn from the success of Sanders’s bold message with this group. They’re up for grabs, as both parties identify them as the cornerstone of Donald Trump’s coalition. Some in the GOP want to throw them out, even though they’ve been the party’s loyal base since Reagan.

Winning more working-class whites would make Clinton’s job easier in November—and might help Democrats reverse their terrible midterm election declines. But Clinton should also learn from Sanders’s experience with black voters, and from her own in 2008. A multiracial coalition that relies on either dog whistles or kettledrums to win white voters isn’t worth building, and can never succeed.