Although the case hasn’t gotten as much mainstream press attention as the forthcoming blockbuster rulings on marriage and on the ACA, the Supreme Court will be issuing a crucial decision on fair housing in the next few weeks in Texas Department of Housing and Community Affairs v. Inclusive Communities Project. A bad decision would reverse decades of positive decisions and progress in  fair housing.

As our nation learned during the riots of the 1960s, and is tragically re-learning today, segregation in housing is both a major cause and effect of our urban problems and inequality. Partly in response, Congress enacted the Fair Housing Act in 1968, with the explicit purpose to “provide, within constitutional limitations, for fair housing throughout the United States.” For almost four decades, every appellate court that has considered the issue and the Department of Housing and Urban Development (HUD) under both Republican and Democratic administrations have interpreted the Act to prohibit conduct that has a discriminatory effect based on race, color, religion, gender, disability, or familial status without a good justification. The issue in Texas Department is whether the Court will overturn that standard and rule that you don’t have a case under the Fair Housing Act unless you can prove specific intent to discriminate.

Why is this important? On a practical level, requiring proof of intent will make fair housing enforcement much more difficult; as one court noted, “clever men may easily conceal their motivations.” More broadly, discrimination and segregation often result from policies that may not be motivated by specific bad intent but that build on historic and systemic patterns of discrimination and lock out racial and other minorities. The “disparate impact” test, which is the legal term for the standard based on unjustified discriminatory effects, has helped combat that problem.

For example, in one case a building policy that imposed a limit of two people per bedroom resulted in the effective eviction from a one-bedroom apartment of a young couple who had just had a child. The policy was challenged based on disparate impact. It turned out there was no good business justification for the policy, and 150 units were opened up for families with children as a result. Similar challenges to policies that excluded disabled veterans by requiring residents to have full-time jobs or zoning restrictions that excluded racial minorities by requiring large lot sizes have helped break down long-entrenched problems of discrimination and exclusion.

All eleven federal courts of appeal that have considered this issue since the 1970s have approved the disparate impact standard. As explained in a brief to the Supreme Court by former Republican and Democratic HUD appointees, HUD has also followed this standard for decades. As a former HUD official and career-long civil rights attorney, I know the importance of the disparate impact test. As I wrote in a law review article more than 35 years ago, “only by concentrating on effect can the issue of discrimination be realistically addressed at all.”

If the Supreme Court overturns the long-accepted disparate impact standard, the continuing problems of discrimination and segregation in our country will only get worse in the years to come. The outcome of this case will have an enormous impact on millions of people throughout America, and on the nature of who we are as a nation.