Federal Police Power
A year before Collector v. Day was decided, the Court held invalid, except as applied in the District of Columbia and other areas over which Congress has exclusive authority, a federal statute penalizing the sale of dangerous illuminating oils. The Court did not refer to the Tenth Amendment. Instead, it asserted that the ”express grant of power to regulate commerce among the States has always been understood as limited by its terms; and as a virtual denial of any power to interfere with the internal trade and business of the separate States; except, indeed, as a necessary and proper means for carrying into execution some other power expressly granted or vested.”
Similarly, in the Employers’ Liability Cases, an act of Congress making every carrier engaged in interstate commerce liable to ”any” employee, including those whose activities related solely to intrastate activities, for injuries caused by negligence, was held unconstitutional by a closely divided Court, without explicit reliance on the Tenth Amendment.
Not until it was confronted with the Child Labor Law, which prohibited the transportation in interstate commerce of goods produced in establishments in which child labor was employed, did the Court hold that the state police power was an obstacle to adoption of a measure which operated directly and immediately upon interstate commerce. In Hammer v. Dagenhart, five members of the Court found in the Tenth Amendment a mandate to nullify this law as an unwarranted invasion of the reserved powers of the States. This decision was expressly overruled in United States v. Darby.
