The Texas Department of Housing and Community Affairs is seen in Austin, Texas. The Supreme Court ruled 5-4 that federal housing laws prohibit seemingly neutral practices that harm minorities, even without proof of intentional discrimination. (Eric Gay/AP)

The Supreme Court on Thursday upheld a key tool that the Obama administration and civil rights groups have used to fight housing discrimination, saying policies do not have to use intentional discrimination in order to be illegal.

Intentional discrimination can be hard to prove, as agencies and businesses seldom adopt policies that show purposeful discrimination. But “disparate impact” can be proved in other ways, including the use of statistics, and has been used since the Fair Housing Act of 1968 was passed.

Justice Anthony Kennedy was joined the court’s four liberal members — Ruth Bader Ginsburg, Stephen G. Breyer, Sonia Sotomayor and Elena Kagan — in finding that was one reason to extend the use of disparate impact.

“In light of the long-standing judicial interpretation of the FHA to encompass disparate-impact claims and congressional reaffirmation of that result, residents and policymakers have come to rely on the availability of disparate impact claims,” Kennedy wrote.

The court’s most consistent conservative dissented. “The court today makes a serious mistake,” Justice Samuel A. Alito Jr. wrote. He was joined by Chief Justice John G. Roberts Jr. and Justices Antonin Scalia and Clarence Thomas.

The case was the third to present the issue. The earlier two cases were withdrawn just before they were to be argued, due to efforts by civil rights groups and the Obama administration, which were fearful of a loss in the Supreme Court.

A Texas group promoting integration argued that state officials had violated the Fair Housing Act by giving a disproportionate share of the tax credits to landlords in minority neighborhoods. The trial judge ruled that the group had failed to show intentional discrimination, but it had proved that the way the credits were allocated had a disparate impact on minority families.