The Supreme Court is established by Article III, Section 1 of the Constitution of the United States, which says: "The judicial Power of the United States, shall be vested in one supreme Court .

The size of the Court is not specified; the Constitution leaves it to Congress to set the number of justices.

When the cases in volume 252 were decided the Court comprised the following nine members: In Missouri v. Holland, 252 U.S. 416 (1920), the Supreme Court considered the extent to which international legal obligations are incorporated into federal law.

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 an earlier treaty between the U.S. and the United Kingdom.

The state of Missouri challenged enforcement of the Act within its jurisdiction, arguing that the regulation of game was not expressly delegated by the U.S. Constitution to the federal government, and was therefore reserved for the states under the Tenth Amendment.