Heart of Atlanta Motel v. United States

Justice Clark, writing for a unanimous Court, upheld the power of Congress under the Commerce Clause of Article I of the Constitution to regulate both interstate and intrastate businesses, public as well as private, that affect the nation's commerce:

[T]he determinative test of the exercise of power by the Congress under the Commerce Clause is simply whether the activity sought to be regulated is "commerce which concerns more States than one" and has a real and substantial relation to the national interest.

The national interest that Congress sought to promote in Title II was undoing racial discrimination. Racial discrimination, in turn, is a moral wrong that the Constitution authorizes Congress to regulate under the national police power, which is the authority to pass legislation that may restrict individual liberties in the interest of promoting the general welfare.

In 1881, the Supreme Court decided a set of cases collectively called the Civil Rights Cases, in which various provisions of the Civil Rights Act of 1875 outlawing discrimination in public accommodations were declared unconstitutional. In the Civil Rights Cases, the Court held that the Fourteenth Amendment, which granted citizenship rights to freed slaves and which was the basis for the Civil Rights Act of 1875, could not be enforced against private businesses. So when Congress next addressed the issue of racial discrimination, in 1964, it used its power under the Commerce Clause as the primary authority for the legislation.

The Commerce Clause proved to be a powerful tool for combatting racism. Although the appellant in Heart of Atlanta Motel claimed that its operation was local, the Court found that the effects of its policies and practices reached far beyond Atlanta and even beyond the state border. In particular, by refusing to provide rooms for African American travelers, many of whom came from out of state on business, the motel was affecting interstate commerce. In Katzenbach v. McClung, decided the same day, the Court used similar logic in applying the Civil Rights Act of 1964 to a small restaurant that purchased its supplies locally and served mostly local customers. Because some of the restaurant's supplies originally came from out of state, its activities had an impact on interstate commerce. Taken together, Heart of Atlanta Motel and Katzenbach v. McClung amply demonstrated that Congress had the means to combat racism in America.