Дело Hammer v. Dagenhart и регулирование детского труда в США.

Hammer v. Dagenhart, 247 U. S. 251 (1918), was a United States Supreme Court decision in which the Court struck down a federal law regulating child labor. The decision was overruled by United States v. Darby Lumber Co. (1941). During the Progressive Era, public sentiment in the United States turned against what was perceived as increasingly intolerable child labor conditions. In response, Congress passed the Keating–Owen Act, prohibiting the sale in interstate commerce of any merchandise that had been made either by children under the age of fourteen, or by children under sixteen who worked more than sixty hours per week. In his majority opinion, Justice William R. Day struck down the Keating–Owen Act, holding that the Commerce Clause did not give Congress the power to regulate working conditions. In his dissenting opinion, Justice Oliver Wendell Holmes Jr. argued that goods manufactured in one state and sold in other states were by definition interstate commerce, and thus Congress should have power to regulate the manufacturing of those goods.

During the Progressive Era, public sentiment in the United States turned against what was perceived as increasingly intolerable child labor conditions. Activities of such groups as the National Child Labor Committee, investigative journalists, and labor groups called attention to unhealthy and unsafe working conditions. Historical material presented by the Smithsonian Institution provides a sense of the motivation behind these concerns in an electronic exhibit on the work of the photographer Lewis Hine:
Over and over, Hine saw children working sixty and seventy hour weeks, by day and by night, often under hazardous conditions. He saw children caught in a cycle of poverty, with parents often so ill paid that they could not support a family on their earnings alone, and had to rely on their children's earnings as a supplement for the family's survival. He saw children growing up stunted mentally (illiterate or barely able to read because their jobs kept them out of school) and physically (from lack of fresh air, exercise, and time to relax and play). He saw countless children who had been injured and permanently disabled on the job; he knew that, in the cotton mills for example, children had accident rates three times those of adults. Responding to the growing public concern, many states sought to impose local restrictions on child labor. In many states, however, the attempt to regulate was ineffective. In addition, manufacturers argued that where restrictions were imposed only in selected states, it placed them at a competitive disadvantage with competitors from states which still placed no restrictions. Unable to regulate hours and working conditions for child labor within individual states, Congress sought to regulate child labor by banning the product of that labor from interstate commerce. The Keating Owen Act of 1916 prohibited interstate commerce of any merchandise that had been made by children under the age of fourteen, or merchandise that had been made in factories where children between the ages of 14 and 16 worked for more than eight hours a day, worked overnight or worked more than sixty hours a week. Roland Dagenhart, who worked in a cotton mill in Charlotte, North Carolina with his two sons, sued, arguing that this law was unconstitutional. A district court ruled the statute unconstitutional, which caused United States Attorney William C. Hammer to appeal to the Supreme Court. The court reasoned that "The commerce clause was not intended to give to Congress a general authority to equalize such conditions". The Court added that the federal government was "one of enumerated powers" and could not go beyond the boundary drawn by the 10th Amendment, which the Court misquotes by inserting the word "expressly":

Justice Holmes dissented strongly from the logic and ruling of the majority. He maintained that Congress was completely within its right to regulate interstate commerce and that goods manufactured in one state and sold in other states were, by definition, interstate commerce. That placed the entire manufacturing process under the purview of Congress, and the constitutional power "could not be cut down or qualified by the fact that it might interfere with the carrying out of the domestic policy of any State". Holmes also took issue with the majority's logic in allowing Congress to regulate goods themselves regarded as immoral, while at the same time disallowing regulation of goods whose use may be considered just as immoral in a more indirect sense: "The notion that prohibition is any less prohibition when applied to things now thought evil I do not understand  to say that it is permissible as against strong drink but not as against the product of ruined lives." At the time, the Eighteenth Amendment, banning the sale, manufacture and transport of alcoholic drink, had been approved by Congress and was being ratified by the states. Holmes also commented on the court's rejection of federal restrictions on child labor: "But if there is any matter upon which civilized countries have agreed—it is the evil of premature and excessive child labor."

In 1922, another ruling, Bailey v. Drexel Furniture, banned Congress from levying a tax on goods produced through child labor entered into interstate trade; both rulings caused the introduction of the Child Labor Amendment. The ruling of the Court was later overturned and repudiated in a series of decisions handed down in the late 1930s and early 1940s. Specifically, Hammer v. Dagenhart was overruled in 1941 in the case of United States v. Darby Lumber Co., The Court in the Darby case sided strongly with Holmes' dissent, which they called "classic". They also recast the reading of the Tenth Amendment, regarding it as a "truism" that merely restates what the Constitution had already provided for, rather than offering a substantive protection to the States, as the Hammer ruling had contended.