Over a hundred years ago, African American thinker and civil rights activist W.E.B. Du Bois scolded his fellow socialists for waffling on the issue of race. At that time, many unions excluded blacks, and socialist parties in the South promoted segregation. Du Bois called the situation hypocritical.

“The essence of Social Democracy is that there shall be no excluded or exploited classes in the Socialistic state; that there shall be no man or woman so poor, ignorant or black as not to count one,” he wrote .

There are echoes of Du Bois in an essay published this week by the Atlantic’s Ta-Nehisi Coates, who criticized Democratic presidential candidate Bernie Sanders for not being radical enough on matters of race. Coates famously made the case for reparations in a 2014 Atlantic article, and won the National Book Award for non-fiction last year for his memoir, "Between the World and Me."

Sanders recently came out against reparations for slavery, which he described as impractical and “very divisive.” Coates responded that, in light of the candidate’s other fanciful policy proposals, it was peculiar he would require realistic thinking on this issue.

“Sanders should be directly confronted and asked why his political imagination is so active against plutocracy, but so limited against white supremacy,” Coates wrote.

He added: “If not even an avowed socialist can be bothered to grapple with reparations … then expect white supremacy in America to endure well beyond our lifetimes and lifetimes of our children.”

The goalposts have moved considerably in the century between Du Bois’s activism and Coates’s. Du Bois was fighting overt racism within the American socialist movement; Coates is criticizing what he perceives as racial indifference in a candidate who identifies as a democratic socialist.

Both writers, though, converge on the same point. Anyone who professes to be a socialist must confront America’s legacy of racial oppression.

Sanders has a racial justice platform, which he published after a series of confrontations with Black Lives Matter activists.  It aims to address police shootings, the war on drugs, the minimum wage, college access, and affordable childcare, among other issues. These are race-neutral policies, for the most part, but they also confront some of the gravest concerns set forth by activists in the black community.

These policies wouldn’t eliminate racism, but they would reduce racial inequality in America. In a certain light, these kinds of investments — which disproportionately benefit African-Americans — start to look a lot like reparations.  If Congress ever commissions a panel, as Coates has suggested, to investigate how to conduct reparations, aspects of Sanders’s platform would not seem out of place on the report.

But Coates has argued that any program of reparations must specifically address the legacy of racism, not arrive at the solution by accident.

The justifications for reparations, as Coates has detailed, are extensive: African-Americans are owed a debt not only for the indignities of slavery, but also for the systematic exploitation that occurred after emancipation. Coates’s main complaint is that Sanders doesn’t appear to reflect this history or moral obligation:

[I]f Bernie Sanders truly believes that victims of the Tulsa pogrom deserved nothing, that the victims of contract lending deserve nothing, that the victims of debt peonage deserve nothing, that that political plunder of black communities entitle them to nothing, if this is the candidate of the radical left—then expect white supremacy in America to endure well beyond our lifetimes and lifetimes of our children.

Coates himself has been vague about what kinds of reparations he supports. But he writes that this is more than just a practical matter; part of the goal of reparations is to force Americans to confront their past.

"What I’m talking about is more than recompense for past injustices—more than a handout, a payoff, hush money, or a reluctant bribe," he wrote in his Atlantic essay last year. "What I’m talking about is a national reckoning that would lead to spiritual renewal."

And he is quite clear that Sanders' current platform doesn't meet that threshold.

Raising the minimum wage doesn’t really address the fact that black men without criminal records have about the same shot at low-wage work as white men with them; nor can making college free address the wage gap between black and white graduates. Housing discrimination, historical and present, may well be the fulcrum of white supremacy. Affirmative action is one of the most disputed issues of the day. Neither are addressed in the ‘racial justice’ section of Sanders platform.

Du Bois, who laid much of the intellectual groundwork for the reparations movement, saw a natural allegiance between racial justice and socialism. His history of Reconstruction emphasized the economic abuses, portraying black sharecroppers as victims not only of racism, but also of capitalism. The inequalities of race and class are connected. Coates' criticism of Bernie Sanders is that he treats them like they are the same.