WASHINGTON — The Supreme Court endorsed a broad interpretation of the Fair Housing Act of 1968 on Thursday, allowing suits under a legal theory that civil rights groups say is a crucial tool to fight housing discrimination.
“Much progress remains to be made in our nation’s continuing struggle against racial isolation,” Justice Anthony M. Kennedy wrote for the majority in the 5-4 ruling. “The court acknowledges the Fair Housing Act’s continuing role in moving the nation toward a more integrated society.”
The court divided along familiar lines, with its four more liberal members — Justices Ruth Bader Ginsburg, Stephen G. Breyer, Sonia Sotomayor, and Elena Kagan — joining Kennedy.
The question in the case was whether plaintiffs suing under the housing law must prove intentional discrimination or merely that the challenged practice had produced a “disparate impact.” Drawing on decisions concerning other kinds of discrimination, Kennedy said the housing law allowed lawsuits relying on both kinds of evidence.
The first kind of proof can be hard to come by, as agencies and businesses seldom announce that they are engaging in purposeful discrimination. “Disparate impact,” on the other hand, can be proved using statistics.
Kennedy wrote that the history of the law and of the civil rights movement supported the broader interpretation.
“In April 1968, Dr. Martin Luther King Jr. was assassinated in Memphis, Tenn., and the nation faced a new urgency to resolve the social unrest in the inner cities,” Kennedy wrote. Congress responded, he went on, by passing the Fair Housing Act.
Civil rights groups and the Obama administration, fearing an unfavorable ruling from the Supreme Court, had worked hard to keep the issue away from the justices. Two earlier cases on the question were withdrawn just before they were to be argued.
The latest case, Texas Department of Housing and Community Affairs v. Inclusive Communities Project, No. 13-1371, was brought by a Texas group that favors integrated housing. The group helps its clients, who are mostly lower-income black families, find housing in the Dallas suburbs, which are mostly white.
The families use housing vouchers, but not all landlords accept them. Landlords receiving federal low-income tax credits, however, are required to accept the vouchers.
The fair housing group 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 Supreme Court returned the case to the lower court for further proceedings, cautioning that allowing disparate-impact suits does not mean they should always succeed. Indeed, Kennedy expressed concern about “abusive disparate-impact claims” and suggested that the case before the court would face headwinds.
“This case,” Kennedy wrote, “may be seen simply as an attempt to second-guess which of two reasonable approaches a housing authority should follow in the sound exercise of its discretion in allocating tax credits for low-income housing.”
In dissent, Justice Samuel A. Alito Jr. wrote that the majority had misread the housing law and the court’s own precedents.
“And today’s decision,” he added, “will have unfortunate consequences for local government, private enterprise and those living in poverty. Something has gone badly awry when a city can’t even make slumlords kill rats without fear of a lawsuit.”
The fair housing law, Alito wrote, bars discrimination “because of” race. He gave several examples of why the phrase should be understood to refer only to intentional discrimination.
For instance, he wrote, “of the 32 college players selected by National Football League teams in the first round of the 2015 draft, it appears that the overwhelming majority were members of racial minorities.”
“Teams presumably chose the players they think are most likely to help them win games,” Alito added. “Would anyone say the NFL teams made draft slots unavailable to white players ‘because of’ their race?”
Chief Justice John G. Roberts Jr. and Justices Antonin Scalia and Clarence Thomas joined Alito’s dissent, which was almost half as long as the majority opinion.
Thomas filed a separate dissent saying that the roots of the majority’s mistake were in a 1971 decision recognizing disparate-impact claims in employment discrimination suits. “I would not amplify its error,” he said of the decision, “by importing its disparate-impact scheme into yet another statute.”
Sherrilyn Ifill, president of the NAACP Legal Defense and Educational Fund, told reporters outside the court that the housing law was critical in bridging the nation’s racial divide, especially in light of the shooting at a black church in Charleston, S.C.
‘‘Anyone who has been paying attention in the last week knows that we can no longer afford to live the way we have as two separate bifurcated parts of this country,’’ Ifill said.
Material from the Associated Press was included in this report.