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 299 were decided the Court comprised the following nine members: In De Jonge v. Oregon, 299 U.S. 353 (1937), the Supreme Court held that the Fourteenth Amendment's due process clause applies freedom of assembly against the states.

The Court found that De Jonge had the right to speak at a peaceful public meeting held by the Communist Party, even though the party generally advocated an industrial or political change in revolution.

However, in the 1950s with the fear of communism on the rise, the Court ruled in Dennis v. United States (1951) that Eugene Dennis, who was the leader of the Communist Party, violated the Smith Act by advocating the forcible overthrow of the United States government.