The case resulted in two opinions from the Supreme Court of the United States, the second of which upheld the constitutionality of the registration requirement against challenges brought under the First and Fifth Amendments.

Its findings read, in part: There exists a world Communist movement which, in its origins, its development, and its present practice, is a world-wide revolutionary movement whose purpose it is, by treachery, deceit, infiltration into other groups (governmental and otherwise), espionage, sabotage, terrorism, and any other means deemed necessary, to establish a Communist totalitarian dictatorship in the countries throughout the world through the medium of a world-wide Communist organization.The Act required any organization qualifying as either a "communist-action" organization or a "communist-front" organization to register with the Attorney General of the United States and provided detailed information about their operations, including offices, finances, printing presses, names and addresses of officers, and in the case of "communist-action" organizations—those determined to be "substantially directed, dominated, or controlled by the foreign government or foreign organization controlling the world Communist movement...and...[that] operates primarily to advance the objectives of such world Communist movement—names and addresses of members.

On November 22, 1950, the Attorney General petitioned the Subversive Activities Control Board for an order to require that the Communist Party of the United States register as a Communist-action organization.

[4] Though the Party challenged the constitutionality of the Act, the Supreme Court did not address these issues in its opinion, delivered by Justice Felix Frankfurter.

Making new findings of fact, the Modified Report reaffirmed the Board's conclusion that the Party was a "Communist-action" organization and recommended that the Court of Appeals affirm its registration order.

[5] The hearings were reopened, further documents were produced, and the Board struck additional testimony though not to the extent that the Party requested.

Fourth and finally, the Court rejected the Party's due process challenge that Congress's findings of a "world Communist movement" predetermined facts that should be left for adjudication.