The Supreme Court case that some say could make it harder to bring racial discrimination lawsuits.

A U.S. congressman is calling for Comcast Corp. “to be broken up,” days before the cable giant is set to face off against Byron Allen, an African American Hollywood entertainment mogul, in a Supreme Court case that some say could make it harder to bring racial discrimination lawsuits.

In a letter Thursday, Rep. Bobby Rush (D., Ill.) told Comcast CEO Brian Roberts that he is “dismayed” that the company might undercut the country’s oldest civil rights law, the Civil Rights Act of 1866. Rush is a member of the House Energy and Commerce Committee.

Rush claimed that Comcast had failed to live up to its promises at the time of acquiring NBCUniversal of making its programming more inclusive. Those promises, critical in getting influential minority groups in Washington to support the merger, were merely for “political expediency,” Rush contended.

“Comcast has enjoyed the largesse — as has the cable industry, in general — of the African American and other minority communities, and has reached such prominence that it now disregard these communities with a cold, callous corporate insensitivity that is stultifying, arrogant, harmful, and intensely painful,” Rush wrote.

At the heart of the dispute is a 2015 lawsuit in which Allen sued Comcast for $20 billion, alleging that the cable company discriminated against him based on race when it refused to carry his channels.