In 1968, Congress enacted the Fair Housing Act to combat segregation in housing. Congress drafted the act to give families two options to challenge discrimination: a claim that someone intentionally discriminated against them on the basis of race and a separate claim that someone adopted a policy or practice that had a disparate discriminatory impact on minority families.

Intentional discrimination cases are notoriously hard to prove because they require evidence of a person’s state of mind. As a result, most housing segregation cases are brought on the second basis: disparate impact. Those cases are no easy lift either. To find a disparate-impact violation, a court must conclude that a challenged practice has a disproportionately negative effect on otherwise similar racial groups and that there is no nondiscriminatory explanation for the practice. Despite that high bar, disparate-impact claims have been the main tool for attacking some of the most persistent practices contributing to housing segregation.

Congress clearly intended to create two paths to challenge housing discrimination. For the past 47 years, appellate courts across the country have uniformly upheld the existence of Fair Housing Act disparate-impact claims. When it amended the law in 1988, Congress did nothing to question that settled understanding. In fact, with overwhelming majorities in both houses, it made the opposite decision, expanding the act to cover additional types of claims. Yet experienced watchers of the Supreme Court believe it is ready to defy Congress and ignore the country’s appellate courts by eliminating the disparate-impact test altogether.

Such a ruling would inevitably result in far more segregated communities. Seventeen states, with both Democratic and Republican governors — from Massachusetts and California to North Carolina and Utah — have joined to warn that jettisoning disparate-impact claims would eliminate “an especially important tool to combat the kinds of discrimination that perpetuate segregation.” That is deeply troubling on its face, but the economic effects are even broader.