There is now a bright, and important, marker in the reparations debate.

In 1988, Jesse Jackson made reparations part of his campaign platform.

In 2016, President Barack Obama dismissed reparations as politically impractical during an interview with Ta-Nehisi Coates, whose Atlantic article sparked renewed interest in reparations.

Now, Elizabeth Warren, who is campaigning on big, bold policy ideas such as breaking up tech giants, has stated her support of a bill that would form a commission to study slavery and develop reparations proposals. It's actually an issue she's evolved on, moving from a more broad-based approach to something more specific.

"Because of housing discrimination and employment discrimination, we live in a world where the average white family has $100 (and) the average black family has about $5," she said at a CNN town hall in Jackson, Mississippi.

"So, I believe it's time to start the national full-blown conversation about reparations in this country," she said. "And that means I support the bill in the House to appoint a congressional panel of experts, people that are studying this and talk about different ways we may be able to do it and make a report back to Congress, so that we can as a nation do what's right and begin to heal."

The bill, first introduced in 1991 by John Conyers and co-sponsored by a handful of others, has never made it out of the House Judiciary Committee. But it now appears it will serve as a kind of litmus test for Democratic presidential candidates as they talk about racial inequality and possible remedies.

Traditionally, commissions are thought of as a way to kick an issue down the road or as a way to appear to be doing something without actually doing anything at all. Yet, what Warren is calling for has for years been seen as politically untenable and easily dismissed.

"This is important, and the major reason I think it's important is that in the other significant instance of reparations being provided, for Japanese-Americans who were incarcerated unjustly, that program was the result of a commission," said William "Sandy" Darity, a Duke University professor who has written extensively on reparations. "There is some sentiment that this isn't a reparations program so it doesn't go far enough. But a commission could be a very important instrument in designing a program."

As for the rest of the field, former San Antonio Mayor Julián Castro backs a reparations commission and has criticized Sen. Bernie Sanders of Vermont for dismissing the idea of cutting a check for the descendants of slaves, given his support for expensive government programs. Sens. Amy Klobuchar of Minnesota and Kamala Harris of California support broad investments in communities of color as a form of reparations. Former Texas Congressman Beto O'Rourke has said he supports a conversation about reparations.

Harris, one of the two black candidates running in the Democratic primary, said at a recent event in South Carolina that "we have to speak truth to what happened."

"For too long, frankly, in our country, for too long we have not had these honest discussions about race. We've just not," she said. "You can look at textbooks in public schools that have erased so much of the history, the awful shameful history on race in this country."

A commission on slavery and its aftermath would be both an accounting for and a reckoning with the cost and damage of America's embrace of a race-based system of oppression. Presidents, in moments of racial unrest, have often called for a "national conversation" on race. A commission on slavery and reparations would be just that.

It would be an extended "teachable moment" on slavery, "sharecropping, convict leasing, Jim Crow, redlining, unequal education and disproportionate treatment at the hands of the criminal justice system," as the Conyers bill states.

The debate around reparations -- what they are, who would get them, who would give them -- goes back centuries. But for the first time, the conversation is being had by multiple candidates for the White House. And, in another first, reparations aren't being dismissed out of hand.

It's a testament to how far the Democratic Party has moved on racial issues, pushed there by President Donald Trump's open embrace of white identity politics, and by the policy-focused and diverse Democratic field and electorate.

"This is an important sea change in the political climate," Darity said.

"Reparations has become a topic where you don't have to duck the term. It's now part of the public arena's discourse."