Hammer v. Dagenhart

The government made its case by showing how destructive child labor was, both to children and to their families. Moreover, the government attorney said that if the federal government did not abolish child labor, any state that tried to abolish it would suffer, because of the unfair competition from child-labor states. In order to protect the public good, therefore, the Keating-Owen Act was necessary.

A majority of the Court did not agree. In the majority opinion, written by Justice Day, the Court held that the power to regulate commerce is the power "to control the means by which commerce is carried on," not the "right to forbid commerce from moving."

It was true that the federal government had prevented some types of interstate commerce. For example, lottery tickets, impure food, and people who had been kidnapped, could not be transported across state lines. But in these cases, Day argued, "the use of interstate transportation was necessary to the accomplishment of harmful results." In the case of the child labor dealt with in the Keating-Owen Act, "the goods shipped are of themselves harmless."

Day admitted that states who did not allow child labor would be at a disadvantage relative to those who did. However, "this fact does not give Congress the power to deny transportation in interstate commerce." Under the Tenth Amendment, states had to be free to make their own decisions.