(Reuters) — The U.S. Supreme Court on Monday threw out a lower court's ruling that had given the green light to comedian-turned-media entrepreneur Byron Allen's $20 billion racial bias lawsuit against Comcast Corp. that accused the cable television operator of discriminating against black-owned channels.

In the unanimous ruling, the nine justices sent the case back to the San Francisco-based 9th U.S. Circuit Court of Appeals to reconsider whether Allen's claims that his failure to land a deal for Comcast to carry channels that he owned was due to racial discrimination were enough to let the case proceed. Mr. Allen is black.

The justices said the 9th Circuit assessed Mr. Allen's claims using the wrong test. “To prevail, a plaintiff must initially plead and ultimately prove that, but for race, it would not have suffered,” conservative Justice Neil Gorsuch, an appointee of President Donald Trump, wrote for the court.

Mr. Allen sued Comcast in 2015 in federal court in Los Angeles, making claims under the Civil Rights Act of 1866, a post-Civil War law that forbids racial discrimination in business contracts. It requires all people to have the same right to make and enforce contracts "as is enjoyed by white citizens."

Critics said the ruling will undermine the ability of plaintiffs to enforce claims under the law.

The Trump administration backed Comcast in the case.

Comcast refused to carry channels operated by Entertainment Studios, owned by Mr. Allen.

Comcast argued that a plaintiff must show early on in a case that a contract was denied solely because of racism or the lawsuit must be tossed. The 9th Circuit ruled last year that lawsuits may proceed if plaintiffs can show that discriminatory intent was one factor among others in the denial of a contract.

Comcast said it was pleased with the ruling and hopes the 9th Circuit would now agree to dismiss Mr. Allen's case.

“We are proud of our record on diversity and will not rest on this record,” Comcast spokeswoman Sena Fitzmaurice said in a statement. “We will continue to look for ways to add even more innovative and diverse programming that appeals to our diverse viewership and continue our diversity and inclusion efforts across the company.”

Comcast had told the court that its decisions to reject Mr. Allen's channels were based on capacity constraints, not race, and that Allen's channels — which include Cars.TV and Comedy.TV — did not show sufficient promise or customer demand to merit distribution. Mr. Allen's company acquired the widely available Weather Channel TV network in 2018, after the case had begun.

Mr. Allen also sued Charter Communications on similar grounds in 2016. The suit against Charter Communications will be guided by Monday's ruling in the Comcast case. Those companies called the lawsuits a “scam” and sought to have them dismissed.

Mr. Allen primarily blamed racial discrimination for the rejections, accusing cable executives of giving insincere or invalid excuses and granting contracts to carry white-owned networks during the same period. Other distributors, including Verizon Communications Inc., AT&T Inc. and DirecTV, carried some of Mr. Allen's programming at the time, court papers said.

As part of the court's adjusted operations in response to the coronavirus pandemic, the ruling was issued online only along with three others in a departure from the normal practice of having the justices sit in their courtroom to announce their opinions from the bench.