The Biden administration is restoring a rule that will require cities, counties and states that receive federal housing funds to examine patterns of residential segregation within their borders and take steps to uproot them, a mandate that was first established by civil rights–era legislation but has proved almost impossible to enact.

President Donald Trump ripped up the previous standard, known as the Affirmatively Furthering Fair Housing rule, which he condemned as a federal push to “abolish the suburbs” in the run-up to the presidential election in 2020. Soon after taking office, President Joe Biden pledged to reverse Trump’s decisions on AFFH and once again take steps toward an elusive goal of erasing color lines in American neighborhoods.

The new Biden rule resembles the AFFH guidance set forth by the US Department of Housing and Urban Development in 2015, but officials say this new version establishes a more streamlined process for identifying civil rights concerns and reporting progress toward desegregation under the rubric of “equity plans.” Officials say this framework will be easier for localities of different sizes to follow, and harder for them to ignore.

Communities that fail to comply with the new fair housing rule could lose access to billions of dollars of federal funding.

“We are done with communities that do not serve people,” Housing Secretary Marcia L. Fudge said at a press conference on Wednesday. “We are going to hold responsible those that we give resources to. We no longer as a federal government can continue to fail the very people we need to help.”

For some 55 years, the Affirmatively Furthering Fair Housing mandate has served up a dilemma: How can federal officials enforce an obligation for local leaders to proactively and voluntarily undo segregation? From the very beginning the measure was controversial: George Romney, who served as housing secretary after the Fair Housing Act was passed, ordered HUD to reject applications for federal funding from jurisdictions that promoted segregation, but he was reeled in by President Richard Nixon.

In subsequent decades, standards for enforcing this mandate fell so low that a trope emerged in the 1990s: If a municipality encouraged schoolchildren to draw posters about fair housing, that was good enough to check off the box.