The Espionage Act of 1917 is a United States federal law enacted on June 15, 1917, shortly after the United States entered World War I. It has been amended numerous times over the years. It was originally found in Title 50 of the U.S. Code (War & National Defense), but is now found under Title 18 (Crime & Criminal Procedure): 18 U.S.C. ch. 37 (18 U.S.C. § 792 et seq.).
It was intended to prohibit interference with military operations or recruitment, to prevent insubordination in the military, and to prevent the support of enemies of the United States during wartime. In 1919, the Supreme Court of the United States unanimously ruled through Schenck v. United States that the act did not violate the freedom of speech of those convicted under its provisions.