WASHINGTON — A cautious Supreme Court on Wednesday seemed to be looking for a narrow way to rule in a racial discrimination case against Comcast, the nation’s largest cable company, by a black entrepreneur who contends his race played a role in the company’s decision not to carry programming from his network.

Civil rights groups have said they feared the court might use the case by Byron Allen and his company, Entertainment Studios Networks, to limit the reach of anti-discrimination laws, but there was little evidence at Wednesday’s argument that the justices were inclined to make a sweeping ruling.

The central question in the case, Justice Samuel A. Alito Jr. said, was “not the big issue that has been portrayed.” Chief Justice John G. Roberts Jr. said the case was “somewhat academic.”

The case concerns a Reconstruction-era federal law that gives “all persons” the same right to “make and enforce contracts” as “is enjoyed by white citizens.”