The Hughes Court (1940-1941). Seated, from left to right: Justices Owen J. Roberts and James C. McReynolds, and Chief Justice Evans Hughes, and Justices Harlan Fiske Stone and Hugo L. Black. Standing, from left to right: Justices William O. Douglas, Stanley F. Reed, Felix Frankfurter, and Frank Murphy.
The Darby Court stated that it did not matter if Congress’s true motivation was to restrict local activity. The Court held that “Whatever their motive and purpose, regulations of commerce which do not infringe some constitutional prohibition are within the plenary power conferred on Congress by the Commerce Clause.” Compare that passage with Chief Justice Marshall’s limiting principle in McCulloch v. Maryland. There he insisted that the Court would have a duty to invalidate a law “should congress under the pretext of executing its powers, pass laws for the accomplishment of objects, not entrusted to the government.”
In overruling Hammer v. Dagenhart, the Court held that Congress has the power to regulate “intrastate activities where they have a substantial effect on interstate commerce.”
Finally, the Court held that the Tenth Amendment “states but a truism that all is retained which has not been surrendered.” As a result, the police power of the states would no longer figure into identifying the “scope” of Congress’s power.
Implied powers during the New Deal
United States v. Darby (1941), unanimously upheld Congress’s power to regulate the wages of local lumber workers. Darby rejected the direct effects test and introduced the substantial effects test. This framework recognized that Congress could do more than simply protect interstate commerce from being burdened or obstructed. Congress also had the power to regulate “intrastate activities where they have a substantial effect on interstate commerce.” The Court’s analysis, by Justice Stone, relied on McCulloch v. Maryland (1819).