The Supreme Court declared unconstitutional the Keating-Owen Child Labor Act of 1916 in 1918, with the ruling in Hammer v. Dagenhart during the Lochner Era.
This law sought to discourage the use of child labor by businesses, by prohibiting the interstate sale of goods produced by factories that employed children under the age of fourteen or mines employing children under sixteen years of age. The basis of the action was the constitutional clause that grants Congress the task of regulating interstate commerce.