Wickard v. Filburn, 317 U.S. 111 (1942),

Wickard v. Filburn, 317 U.S. 111 (1942), was a U.S. Supreme Court decision that dramatically increased the power of the federal government to regulate economic activity. A farmer, Roscoe Filburn, was growing wheat to feed his chickens. The U.S. government had imposed limits on wheat production based on acreage owned by a farmer, in order to drive up wheat prices during the Great Depression, and Filburn was growing more than the limits permitted. Filburn was ordered to destroy his crops and pay a fine, even though he was producing the excess wheat for his own use and had no intention of selling it.
The Supreme Court, interpreting the United States Constitution's Commerce Clause under Article 1 Section 8 (which permits the United States Congress "To regulate Commerce with foreign Nations, and among the several States, and with the Indian Tribes;") decided that, because Filburn's wheat growing activities reduced the amount of wheat he would buy for chicken feed on the open market, and because wheat was traded nationally, Filburn's production of more wheat than he was allotted was affecting interstate commerce, and so could be regulated by the federal government.