In the 1964 case of Katzenbach v. McClung, the U.S. Supreme Court ruled that Congress acted within its power under the Commerce Clause of the Constitution when it enacted the Civil Rights Act of 1964, which prohibited racial discrimination in restaurants as this impacted interstate commerce. The case was brought by Ollie's Barbecue, a family-owned restaurant in Birmingham, Alabama that refused to serve black customers in its main dining area. The owners argued that since their business was mostly local and did not engage directly with interstate commerce, they were exempt from federal regulation under said act. However, Justice Tom C Clark delivered an unanimous decision stating that even if a portion of food served came from out-of-state suppliers (46% for Ollie’s), then such businesses had enough connection to interstate commerce to be regulated by Congress.

In the case of Katzenbach v. McClung, Justice Potter Stewart dissented from the majority opinion. He argued that while he agreed with the Court's decision in Heart of Atlanta Motel Inc. v United States (which upheld Congress' power to regulate interstate commerce), he could not agree with its application in this particular case involving Ollie’s Barbecue, a local restaurant in Birmingham, Alabama. According to him, there was insufficient evidence to prove that racial discrimination by this specific restaurant had a direct and substantial effect on interstate commerce - which is necessary for federal regulation under the Commerce Clause of Constitution. Therefore, applying Title II of Civil Rights Act 1964 (prohibiting racial discrimination by places of public accommodation) would be an overreach into matters reserved for state law or private resolution.