Pennsylvania Coal Co. v. Mahon

In Pennsylvania Coal Co. v. Mahon, 260 U.S. 393 (1922), the U.S. Supreme Court first articulated the notion that government activities short of direct seizure could constitute takings.

Justice Oliver Wendell Holmes, Jr. wrote the opinion for Court, with only Justice Louis Brandeis dissenting. Justice Holmes wrote, "But the question at bottom is upon whom the loss of the changes desired should fall," and he wrote that the public, not the private company, should bear that loss.

The Court eventually developed a framework for analyzing "regulatory takings" claims. The modern test states that regulation effects a taking if it deprives an owner of all or substantially all economic or productive use of his or her property.