Which Supreme Court decision struck down the Keating-Owen Child Labor Act of 1916, signaling limits on federal regulation of child labor?

• A. United States v. E. C. Knight Co.
• B. Lochner v. New York
• C. Hammer v. Dagenhart
• D. Plessy v. Ferguson

Answer: (C)

The main idea is the limits of federal power under the Commerce Clause and the distinction between regulating interstate commerce and regulating production within a state. Hammer v. Dagenhart held that the Keating-Owen Act of 1916, which tried to prohibit the shipment of goods produced with child labor across state lines, overstepped Congress’s authority because it targeted production and labor practices inside states, not a direct regulation of interstate commerce. In other words, the federal government can regulate trade between states, but it cannot regulate the production decisions that occur entirely within a state, so the Act was unconstitutional. This decision highlighted how far federal regulation could reach during the Progressive Era, a boundary later reconsidered and expanded in the New Deal era.