The Supreme Court on Monday unanimously ruled against an African American-owned media company that alleged Comcast had racially discriminated against the network when it refused to enter into a contract for its programming. 

Writing for the 9-0 majority, Justice Neil Gorsuch ruled that federal civil rights lawsuits concerning contracting decisions must show that race was the determining factor behind an injury, not simply part of a company’s motivation not to move forward with a deal.

“Under this standard, a plaintiff must demonstrate that, but for the defendant’s unlawful conduct, its alleged injury would not have occurred,” Gorsuch wrote. 

The decision returns the case to a lower federal appeals court to reconsider in light of the stricter standard the justices set on Monday for lawsuits alleging race-based contract discrimination.

Comcast applauded the ruling, saying its decision not to contract with the company, Entertainment Studios Network, was based on legitimate business reasons.

“We are pleased the Supreme Court unanimously restored certainty on the standard to bring and prove civil rights claims,” the company said in a statement. “The well-established framework that has protected civil rights for decades continues.”

Civil rights groups said the opinion would make it harder for racial discrimination suits to survive beyond the initial stage of litigation.

“This ruling weakens our nation’s oldest civil rights statute and may shut the courthouse door on some discrimination victims who, at the complaint stage, may simply be without the full range of evidence needed to meet the court’s tougher standard,” Kristen Clarke, president of the Lawyers’ Committee for Civil Rights Under Law, said in a statement.

The case arose after Comcast declined to carry Entertainment Studios Network’s suit of television programming, with the cable giant claiming it lacked the bandwidth. The network said the explanation was pretextual, alleging that Comcast had adequate bandwidth, and noting evidence suggesting that race may have played a role in the decision. 

Entertainment Studios sued under a federal civil rights statute enacted after the Civil War. That law, Section 1981 of Title 42 of the United States Code, prohibits racial discrimination in contracting.

The 9th Circuit Court of Appeals had allowed the studio’s suit to move forward, finding that race may have been a motivating factor in Comcast’s choice not to forge a partnership.

The motivating-factor standard is one of two approaches that federal courts around the country have applied when deciding whether to allow such cases to move beyond the initial stages.

The stricter standard, which the justices established as the uniform standard nationwide with their Monday ruling, requires plaintiffs to show that race was the determining factor, known as the “but-for” cause, in a decision not to enter into a contract.

Justice Ruth Bader Ginsburg wrote a concurring opinion to emphasize that federal law prohibits racial discrimination throughout the entire run-up to a contract, not just the final decision.