The other big US Supreme Court decision we should be celebrating is one no one’s talking about

This post has been corrected.

There was much excitement last week over the US Supreme Court’s rulings in favor of same-sex marriage and Barack Obama’s health-care reforms that few people noticed another ruling that could be at least as far-reaching. It’s a first—and admittedly still tentative—step in dismantling many aspects of racial and gender discrimination that, long after they were made illegal, remain structurally entrenched in America.

Even as explicit discrimination becomes less and less common in the US, implicit discrimination remains widespread. It exists in the form of laws or policies that are seemingly color- or gender-blind, but in practice discriminate—often unintentionally—against women or minorities. In the past couple of decades, social-justice campaigners have sought to bring such cases under a “disparate-impact” theory, which uses statistics to show a pattern of discrimination, rather than imposing on the plaintiff the burden of proving intent to discriminate. Yet courts, especially criminal courts, have often insisted on proof of intent, a hurdle that has often proved too high for plaintiffs to clear.

In criminal law, for example, there was the infamous case of McCleskey v. Kemp. Evidence, in the form of a comprehensive research study, showed a “racially disproportionate impact” of the Georgia death penalty on black defendants. Yet the Supreme Court ruled this insufficient to overturn the death penalty without showing a “racially discriminatory purpose.”

Similarly, in civil law, the court ruled in Washington v. Davis that laws that have a racially discriminatory effect, but which the plaintiff cannot demonstrate were enacted with the intent to discriminate, are not unconstitutional. That ruling has protected from challenge some laws and policies which many see as unjust.

The ruling on June 25, however, could change this legal landscape. The Supreme Court agreed in a 5-4 decision that the Texas housing department had violated the Fair Housing Act, and engaged in racial discrimination, by putting too much subsidized housing in predominantly black urban neighborhoods, and too little in white suburban neighborhoods. The disparate impact was that this discouraged black people from moving to white areas, and perpetuated segregation.

Unfortunately, the court tempered its own ruling by limiting disparate-impact claims to cases where a law or policy raises “artificial, arbitrary, and unnecessary barriers.” That gives lower courts a lot of leeway in interpretation. And it said that purely statistical evidence of disparate impact isn’t enough; plaintiffs must also prove that a law or policy caused that impact, which will often be hard. Nonetheless, this ruling potentially sets a precedent for using disparate-impact theory to combat discrimination in many areas besides housing.

One such area is racial and gender discrimination in employment. Although disparate-impact theory can already be used in such cases, it’s heavily constrained. In Griggs v. Duke Power, the Supreme Court ruled that, under Title VII of the Civil Rights Act, if employment tests disparately impact racial minority groups, such tests are discriminatory unless they can be shown to be “reasonably related” to the job for which the test is required. However, even though this disparate-impact theory of action was later codified into Title VII, some justices, like Antonin Scalia, have argued that as a litigation strategy, it’s unconstitutional. Also, Griggs has also been narrowly construed, so that people who have experienced racial or gender discrimination in the workplace have often still faced a heavy burden in proving discriminatory intent. As a result, employment discrimination cases are among the hardest to win. Yesterday’s ruling may help make it easier to use a disparate-impact framework in such cases.

A second area is the use of a person’s genetic data to discriminate in employment and for insurance purposes. The Genetic Information Non-Discrimination Act (GINA), passed in 2009, makes such discrimination illegal. But it doesn’t explicitly allow cases to be brought under a disparate-impact framework. Yesterday’s ruling could finally allow for that, enabling employees to sue employers for discrimination on the basis of established statistics or patterns of excluding people with genetic traits for disease.

A third important area concerns formerly incarcerated women. There is evidence that so-called “collateral consequences of conviction”—such as rules that deny ex-prisoners food stamps or access to certain kinds of jobs after their release—have a disparate impact on women, a form of modern-day “scarlet letter.” Yesterday’s ruling could open the way for women affected by these collateral consequences to launch disparate-impact claims.

There is also a form of discrimination that is only just becoming recognized, but is likely to become much more important as technology progresses. As companies and government agencies collect and analyze more and more data on people—from their online shopping habits, social-media activity, and so on—the way the data are used (for instance, in setting prices for products) can end up inadvertently discriminating against the poor, women or ethnic minorities. Here, proving intent to discriminate is impossible; the discriminatory effects are typically the result of applying machine-learning algorithms. Scholars such as Solon Barocas, of Princeton University, and Andrew Selbst have shown how a disparate-impact framework could be used to show data discrimination in such cases.

There are other areas such as voting, education, or drug laws, where the disparate-impact framework might now be used to tackle racial and gender disparities. And though the Supreme Court’s ruling constrained the use of disparate-impact theory, the government could expand it by codifying it into law, as it did with Title VII. Though it will be a long and hard legal and political battle, this new ruling holds much promise for tackling the inequalities that, decades after overt discrimination against women and minorities was abolished, still remain entrenched in America.

We welcome your comments at ideas@qz.com.

Correction: This post incorrectly identified Solon Barocas’s affiliation and specialty. It was updated with the correct information and the name of his co-author.

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