That two leading Democratic candidates have embraced reparations — the concept that the federal government should both acknowledge the ongoing legacy of slavery and discrimination and provide compensatory payment to those affected — is a major shift from past presidential campaigns and a win for activists who have tried to push the issue into the mainstream for decades. Julián Castro, the former cabinet secretary who is also running for president, has also indicated that he would support reparations.

Even among the 2020 Democrats who stopped short of endorsing reparations, several have laid out robust policies aimed at closing the gap in wealth between black and white families. Scholars estimate that black families in America today earn just $57.30 for every $100 in income earned by white families, according to the Census Bureau’s Current Population Survey. For every $100 in white family wealth, black families hold just $5.04.

Senator Cory Booker’s “baby bonds” policy aims to help poorer children by giving them a government-funded savings account that could total up to $50,000 for the lowest income brackets. The plan has been praised by liberal scholars, who think it could go a long way in helping lower-income Americans begin to build wealth. And Senator Kirsten Gillibrand has endorsed a proposal to allow Americans without checking accounts to bank at the local post office; a disproportionate percentage of America’s unbanked population are people of color.

María Urbina, national policy director for the progressive group Indivisible, said that after years of being pushed by activists, the Democratic Party was getting closer to applying its liberal values to racial equality. Policies like reparations or “baby bonds” that seek to close the racial wealth gap, she said, should be viewed similarly to idealistic programs that have been embraced by Democrats seeking the presidential nomination, including the Green New Deal and “Medicare for all.”

“We want folks who are being ambitious, not just working within the margins and the contours of what we had before, but sort of reimagining things on our own terms and being really aspirational,” Ms. Urbina said.

Sandy Darity, a Duke University professor who is a leading scholar on reparations and the racial wealth gap, said he believes more black Americans may come to see reparations as a defining issue for their support.

“There is a point in black Americans making a collective decision to treat a candidate’s attitude toward reparations as a litmus test for supporting them,” Dr. Darity said. “I think if folks had paid closer attention to the fact that Barack Obama was against reparations, they would have not been as disappointed by his presidency, because they would have had more realistic expectations about what he was likely to do.”