Missouri v. Holland, 252 U.S. 416 (1920) is a United States Supreme Court case concerning the extent to which international legal obligations are incorporated into federal law under the U.S. Constitution. The case centered on the constitutionality of the Migratory Bird Treaty Act of 1918, which prohibited the killing, capturing, and selling of certain migratory birds pursuant to a treaty between the U.S. and the United Kingdom. The state of Missouri challenged the enforcement of the Act within its jurisdiction, arguing that the regulation of game was not expressly delegated to the federal government by the U.S. Constitution and therefore was reserved for the states under the Tenth Amendment; accordingly, the U.S. government had no constitutional right to enter into a treaty concerning game regulation. In a 7–2 decision, the Court upheld the Act as constitutional, since it was enacted pursuant to the federal government's express power to make treaties and to enact laws pursuant to treaties, which the Supremacy Clause of the Constitution elevates above state law. The Court also reasoned that protecting wildlife was in the national interest and could only be accomplished through federal action. Missouri is also notable for Justice Oliver Wendell Holmes's articulation of the legal theory of a "living constitution", which purports that the Constitution changes over time and adapts to new circumstances without formal amendments. Facts Congress had previously passed laws regulating the hunting of migratory waterfowl on the basis that such birds naturally migrated across state and international borders freely, and hence the regulation of the harvest of such birds could not realistically be considered to be province solely of individual states or groups of states. However, several states objected to this theory, and twice successfully sued to have such laws declared unconstitutional, on the premise that the U.S. Constitution gave Congress no enumerated power to regulate migratory bird hunting, thereby leaving the matter to states pursuant to the Tenth Amendment. Disgruntled with these rulings, Congress then empowered the State Department to negotiate with the United Kingdom—which at the time still largely handled the foreign relations of Canada—a treaty pertaining to this issue. The treaty was subsequently ratified and came into force, requiring the federal government to enact laws regulating the capturing, killing, or selling of protected migratory birds, an obligation that it fulfilled in the Migratory Bird Treaty Act of 1918. The state of Missouri requested that U.S. Game Warden Ray