Over half a century on from Brown v. Board of Education, segregation in America's school system is still rampant. The failure has been a thoroughly bipartisan one, and it looks like the reckoning may finally come to the Democratic Party: Rich white school districts hiving themselves off from poorer minority communities — taking their resources with them — is splitting progressive coalitions across the country. At the recent Democratic presidential debates, Sen. Kamala Harris (D-Calif.) made waves when she went after former vice president Joe Biden for his opposition to busing back in the 1970s.

As welcome as this new frank moral dialogue is, it risks passing over the basic economic infrastructure underlying America's school segregation problem. Simply put, a huge portion of public school district funding in the U.S. is drawn from local property taxes. As a result, school resources have been inextricably tied to disparities in wealth and home ownership which are some of the most clear and obvious manifestations of generations of racial discrimination. That linkage must be broken. Moreover, we should move to a system where most, if not all, school funding is distributed out from the national level.

Right now, about 45 percent of all school funding comes from taxes assessed at the local level. For the most part, that means property taxes: i.e. a tax on the value of the home or business establishment you own. Another 45 percent comes from state governments, which can rely on both property taxes and other taxes. Finally, the remaining 10 percent comes from federal spending, which is financed by federal income taxes and capital gains taxes and the like.

The problem with this setup is that America is also a brutally unequal country. The gap in both incomes and wealth — like the value of your property — between our richest and poorest citizens is absolutely immense. On top of that, rich and poor tend to cluster, leading to vertiginous inequality from neighborhood to neighborhood.

As a result, some school districts sit upon extremely privileged populations with high property values, which leads to generous local and property tax returns, which leads to much more generous funding for that district’s schools. While the bulk of U.S. school districts spend just under $10,000 per student, there is a long tail of districts that extends out well past $30,000. Families, in turn, fight like hell to claw their way into the wealthiest neighborhoods — not just because living in those places gives them access to more economic opportunity, but because it gives their children much more access to educational opportunity.

As for the schools left behind, they don't have the resources to pay their teachers well and to attract talent; they're perpetually under staffed; they can't provide students support and counseling rather than merely suspending or expelling them; they have to cram more students into fewer classes; they have fewer books and computers and other tools to provide; they often can't even fix their roofs or make other basic repairs.

This is all pure tax and spending policy interacting with the unequal distribution of wealth and income. With our current system, we'd have vast inequities from school to school even if race didn't play a role in U.S. history at all.

But it did. After the abolition of slavery, black Americans were thrown into the economy without any prior resources, and any attempt to redress that imbalance died with the end of Reconstruction. After that, policies all across America, from official segregation to redlining (the practice of denying loans to people living in majority-Black neighborhoods), sought to prevent African-Americans from ever building up their own wealth and to permanently sequester them in the underclass. Thus the inequality that separates school districts is both economic and racial all at once.

American jurisprudence has left education to the states, as the Constitution gives the federal government no explicit power in the matter. But there have been various state-level attempts to centrally gather the proceeds of local taxation under the state government, and distribute them more equitably among the state's schools.

Unfortunately, these reforms tend to be rare and to die often. For one thing, rich people obviously don't like them, and rich people tend to have more clout at the local and state level, versus the national level where non-rich voters can make maximal use of their greater numbers. State and local taxes also tend to fall much harder on the poor than national taxes. And states with poorer populations have to tax away a bigger share of household income to fund the same level of public services.

Finally, state budgets are pro-cyclical: Unlike the federal government, state and local governments can't print their own supply of U.S. dollars. When a recession hits, a state's tax returns fall, and thus its spending must be cut. The Great Recession massively reduced state-level education spending, from which about half the states have yet to recover. (Local spending did not fall as far and recovered more quickly.) That states can't print their own dollars also makes it much more financially dangerous for them to borrow to fill the gap.

Basically, the combination of rampant inequality, the inevitability of recessions, and reliance on state and local taxes, all renders our national school system wildly unjust and dysfunctional. What can we do about it?

Well, the federal government can't take over the education system, or dictate to states and localities how to distribute the money. But it can cajole the states into mending their ways.

Total spending on education at all levels of government was $611 billion in 2015. The federal government could simply offer that amount of money (or more!) to the states, divvied up on a per-student basis, and portioned out to each state based on their student population. It would be up to each state whether to take the money or not. But if they chose to take it, the federal government could set the condition that the state must equalize all its per-student school funding across the board.

As education is one of the biggest burdens on state budgets, a generous enough federal offer would be almost impossible to refuse.

This would not be a panacea. Student achievement is dependent on a whole host of social factors schools themselves can't address. But resources for the schools themselves still matter a great deal. Research shows that low-income students' educational achievement improves substantially when their school's funding increases. Indeed, the very fact that previous desegregation and busing efforts had such a dramatic impact on student achievement testifies to the importance of school funding.

Ending our schools' reliance on local property taxes and shifting their funding to the national level won't be sufficient, all by itself, to dismantle America's legacy of educational segregation. But we also won't get very far if we don't do this.