Among the most-noticed flashpoints in last night’s Democratic presidential debate was an emotional exchange between Senator Kamala Harris (D-CA) and former vice president Joseph Biden on the topic of school integration. In the back and forth, Harris spoke of the importance of having the opportunity, as a black child, to attend an integrated school in California and chastised Biden for his opposition to busing to achieve integration. Biden defended his record and said he was a strong supporter of civil rights throughout his career.

Setting aside the merits of the two candidates’ argument, a couple of things stand out about the discussion: the unprecedented attention paid to school integration in a presidential debate, and its continuing relevance to the country more than six decades after segregation was formally struck down by the U.S. Supreme Court.

Last night was the first time in decades that the critical issue of school integration took center stage in a major presidential debate.

Last night was the first time in decades that the critical issue of school integration took center stage in a major presidential debate. This discussion was long overdue. Fifty years of research suggest that one of the most important things we can do to promote social mobility in America is to give disadvantaged children a chance to go to socioeconomically and racially integrated schools. Low-income fourth-graders in economically mixed schools perform as much as two years ahead of low-income students in high-poverty schools on the National Assessment for Educational Progress in mathematics. If we want to break the cycle of poverty, few interventions are as important as efforts to give children a chance to attend high-quality integrated schools.

Moreover, at a time of deep national division over race, class, and religion, integrated public schools can serve as the glue that holds our society together. When schools are segregated—when white Christian students do not come to know children who are Muslim or Mexican-American—it is much easier for politicians to demonize minority populations than when schools are integrated and children come to appreciate their common humanity.

While the discussion of school diversity on the national stage was fully welcome, the exchange took on the unfortunate tone of a history lesson. Challenging former vice president Biden, Senator Harris used the past tense in asking, “were you wrong to oppose busing?” as if the discussion were related to a bygone era.

In fact, school integration is very much an issue in the present. True, the policies have morphed since the days of court-ordered compulsory busing for desegregation in the 1970s. Today, many school districts emphasize integration by socioeconomic status as much as by race. And they tend to use voluntary incentives for integration, such as special magnet school themes or teaching approaches, rather than compulsory busing. But integration efforts are alive and well. The Century Foundation has identified 100 school districts and charter school organizations that are actively promoting school integration. These districts serve more than 4 million students.

I have watched in awe as students have led the way in framing the discussion and urged their elders to take swift action.

For example, the nation’s largest school district, New York City, is now engaged in the most thorough-going debate over school integration that the city has seen in more than fifty years. As a member of Mayor Bill de Blasio and Chancellor Richard Carranza’s School Diversity Advisory Group, I have watched in awe as students have led the way in framing the discussion and urged their elders to take swift action. These students realize that segregation remains an enormous challenge sixty-five years after Brown v. Board of Education was decided, and we cannot wait any longer to take action.

With the issue of school diversity thrust onto the national stage, it is time for policymakers to commit to a range of bold ideas for reform. As Halley Potter, Kimberly Quick, and I outlined in a recent Century Foundation report, presidential candidates and policymakers in Congress could take several steps to support school integration. The federal government currently invests 151 times as much money addressing the effects of poverty and concentrated poverty as it does to prevent or undo concentrations of poverty in the first place. We call for boosting federal spending on integration by $500 million; adopting an Economic Fair Housing Act to reduce exclusionary zoning that discriminates by income and race; and requiring federal pre-clearance of efforts by school districts to secede.

In the upcoming presidential debates, candidates should debate and discuss the critical issue of school integration, treating it as the contemporary challenge it is. Segregation remains “the problem we all live with,” and attacking it must be front and center in the fight for a fairer society.