The U.S. Supreme Court will hear arguments Wednesday morning in a case that pits a black media mogul against Comcast, accusing the cable giant of violating Reconstruction-era protections against racial bias.

Byron Allen filed his $20 billion lawsuit under the nation’s oldest civil rights statute: an 1866 law ensuring newly freed African Americans the same right to enter into contracts as any white citizen. He alleges Comcast discriminated against him when it refused to carry channels by his company, Entertainment Studios Network. But the cable provider says its decision was based on “insufficient consumer demand” for the general interest programming.

The question before the court is whether, as Comcast contends, Allen must show that race was the sole driver of Comcast’s decision.

“Imagine somebody goes to a hotel to rent a room and the clerk says, ‘We’re not renting a room to you because we don’t have rooms available and we don’t rent rooms to black people,’" said Erwin Chemerinsky, dean of University of California’s Berkeley School of Law, who will argue on Allen’s behalf. “Under Comcast’s theory, that wouldn’t be enough to prove discrimination.”

This could be the most important civil rights case before the Supreme Court this term, said Kristen Clarke, president and executive director of the National Lawyers’ Committee for Civil Rights Under Law. Discovery and trial processes are crucial in understanding whether racial discrimination motivated an action, Clarke said, and requiring victims to meet that burden of proof when they first plead their case would be a “death knell” for the civil rights statute.

“A negative ruling by the court will literally cut out the heart of this most important law by requiring victims of discrimination to demonstrate that race and nothing more influenced the contested action,” Clarke said. “We would essentially shut the courthouse door on most people seeking to invoke protections of this law.”

Comcast said its argument is consistent with previous interpretations of the statute and rejects the notion that its stance would set back civil rights protections.

“We have been forced to appeal this decision to defend against a meritless $20 billion claim,” Sena Fitzmaurice, a spokeswoman for Comcast, said in a statement emailed to The Post. “Our argument at the Supreme Court is narrowly focused. We are not seeking to roll back any civil rights laws.”

Fitzmaurice said the case “cannot detract from Comcast’s strong civil rights and diversity record” and pointed to other black-owned channels carried by Comcast with programming aimed at African American audiences, including Revolt, the music network launched by Sean Combs, and Aspire, owned by Magic Johnson Enterprises.

Allen’s case has garnered support from dozens of civil rights organizations, legal experts and lawmakers, as well as presidential candidates Sen. Kamala D. Harris (D-Calif.), Sen. Cory Booker (D-N.J.) and South Bend, Ind., Mayor Pete Buttigieg. The Lawyers’ Committee, headed by Clarke, and the NAACP Legal Defense and Educational Fund have both filed briefs in support of Allen but did not take a position on the merits of his claims.

“In pursuing this case to the Supreme Court … Comcast is putting corporate profits ahead of public interest, and is employing a scorched earth policy to defend a corporate business decision,” Rep. Bobby L. Rush (D-Ill.) said in a letter to Comcast’s chief executive, Brian Roberts, adding he believes Comcast “needs to be broken up.”

Section 1981 of the Civil Rights Act of 1866 was designed to safeguard equal opportunities for Americans to work, bank, shop, rent or buy a home, and become entrepreneurs without racial discrimination, civil rights groups said in the briefs. It protects a broad swath of people, including independent contractors in the gig economy and consumers racially profiled by retailers, in scenarios not covered by other major civil rights statutes, they said. And unlike the Civil Rights Act of 1964, the older statute has no cap on damages.

Allen, 58, sued Comcast in February 2015 for refusing to feature ESN’s lifestyle channels, including Comedy.TV, Recipe.TV, MyDestination.TV, Cars.TV and Pets.TV, though they appeared on Verizon, DirecTV, AT&T and DISH programming. For eight years, Comcast gave the network “the runaround with false promises of carriage,” Allen’s lawyers argued. Comcast said it lacked “sufficient bandwidth” for the ESN channels but launched several “lesser-known, white-owned” channels in the same period.

By way of explanation, Allen’s lawyers allege in their brief, one Comcast executive told ESN, “We’re not trying to create any more Bob Johnsons,” referring to the media magnate and co-founder of Black Entertainment Television.

“I’ve never said they don’t do business with black people,” Allen told The Post. “This has always been about a lack of true economic inclusion.”

A district court dismissed Allen’s suit multiple times before the U.S. Court of Appeals for the 9th Circuit reversed that decision in November 2018.

The Justice Department and U.S. Chamber of Commerce filed briefs in support of Comcast, arguing the appeals court erred in deciding that a plaintiff could win by showing that race was just one factor in a decision not to enter into a contract.

“In so doing, the court arrived at a rule that does not apply to any other federal anti-discrimination law: A defendant is subject to damages liability under Section 1981 solely because the plaintiff can prove that an illegitimate motive played a part in the defendant’s conduct, even if the defendant would have taken the challenged action without regard to any protected characteristic,” wrote Solicitor General Noel J. Francisco.

Michael Foreman, a law professor and director of the Civil Rights Appellate Clinic at Pennsylvania State University, called the Trump administration’s support of Comcast “a significant departure” in how the U.S. government has previously addressed race discrimination.

“Given how divided our country is, and that we still have issues of race discrimination … I struggle with whether our justices are willing to say that some level of race discrimination is permissible, which is what they would be saying,” Foreman said.