Lochner V. New York

Lochner v. New York, 198 U.S. 45 (1905), was a landmark United States Supreme Court case which held that "liberty of contract" was implicit in the Due Process Clause of the Fourteenth Amendment. The case involved a New York law that limited the number of hours that a baker could work each day to ten, and limited the number of hours that a baker could work each week to 60. By a 5–4 vote, the Supreme Court rejected the argument that the law was necessary to protect the health of bakers, deciding it was a labor law attempting to regulate the terms of employment, and calling it an "unreasonable, unnecessary and arbitrary interference with the right and liberty of the individual to contract."

Lochner is one of the most controversial decisions in the Supreme Court's history, giving its name to what is known as the Lochner era. In the Lochner era, the Supreme Court issued several controversial decisions invalidating federal and state statutes that sought to regulate working conditions during the Progressive Era and the Great Depression.

During the quarter-century that followed Lochner, the Supreme Court also began to use the Due Process Clause of the Fourteenth Amendment to protect personal (as opposed to purely property) rights, including freedom of speech and the right to send one's child to private school (which was the beginning of the line of cases which found a right to privacy in the Constitution). The Lochner era ended with West Coast Hotel Co. v. Parrish (1937), in which the Supreme Court took an expansive view of the government's power to regulate economic activities.