# United States v. Darby The unanimous Supreme Court decision of **February 3, 1941**, written by Justice Harlan F. Stone, that upheld the Fair Labor Standards Act of 1938 as a valid use of the [[Commerce Clause]] and overruled [[Hammer v. Dagenhart]] (1918). It is the case that formally ended [[Dual Federalism]] as constitutional doctrine. Its most quoted line concerns the [[Tenth Amendment]], which the Court said "states but a truism that all is retained which has not been surrendered." In other words, the amendment adds no limit of its own on federal power; it only confirms that the states keep what the Constitution did not give away. Later decisions such as [[Printz v. United States]] have treated the amendment as doing more work than that. ## Connections - [[Dual Federalism]] · [[Hammer v. Dagenhart]] · [[Commerce Clause]] · [[Tenth Amendment]] - [[New Deal]] · [[Wickard v. Filburn]] · [[Cooperative Federalism]]