In 1918, the US Supreme Court ruled in Hammer v. Dagenhart, striking down a federal law aimed at limiting child labor. Passed only two years before, the Keating-Owen Act had barred the shipment across state lines of goods produced in factories that hired children under 14 and mines that employed children under 16. It had also prohibited children 16 and under from working at night, for more than 8 hours a day, or for more than 6 days a week. This law reflected a growing national interest in protecting children from dangerous working conditions.
But in a 5–4 decision, the Court found that Congress had gone too far. Writing for the majority, Justice William R. Day argued that manufacturing happens within individual states, not across state lines. Because of that, he said, Congress had no authority to regulate factory labor.
Supporters of the decision warned that if Congress could regulate local workplaces this way, it could reach into almost any part of daily economic life. In their view, the Constitution set clear limits on federal power, and this law crossed that line.
Critics, however, saw something different. They argued that the ruling made it harder to address serious problems that stretched across state boundaries, especially in industries like textiles and agriculture where child labor was widespread.
More than a century later, Hammer v. Dagenhart still highlights a basic question in American life: when a problem affects the whole country, who should act—the states, or the federal government? The answer has changed over time, but the debate itself hasn’t gone away.
