This case is here to review the judgment of the Court of Appeals for the District of Columbia affirming an order of the Subversive Activities Control Board that petitioner register with the Attorney General as a 'Communist-action' organization, as required by the Subversive Activities Control Act of 1950, Title I of the Internal Security Act of 1950, 64 Stat. 987, 50 U.S.C.A. § 781 et seq. That Act sets forth a comprehensive plan for regulation of 'Communist-action' organizations. Section 2 of the Act describes a world Communist movement directed from abroad and designed to overthrow the Government of the United States by any means available, including violence. Section 7 requires all Communist-action organizations to register as such with the Attorney General. If the Attorney General has reason to believe that an organization, which has not registered, is a Communist-action organization, he is required by § 13(a) to bring a proceeding to determine that fact before the Subversive Activities Control Board, a five-man board appointed by the President with the advice and consent of the Senate and created for the purpose of holding hearings and making such determinations. Section 13(e) lays down certain standards for judgment by the Board.
If the Board finds that an organization is a Communist-action organization, it enters an order requiring the organization to register with the Attorney General. § 13(g). Section 14 provides the right to file a petition for review of Board action in the Court of Appeals for the District of Columbia, with opportunity for review by this Court upon certiorari. Once an organization registers or there is outstanding a final order of the Board requiring it to register, several consequences follow with respect to the organization and its members, but these need not now be detailed. See §§ 4, 5, 6, 7, 8, 10, 11, 15, 22, 25, 50 U.S.C.A. §§ 783-787, 789, 790, 792(a, e, g), 793, 794; 8 U.S.C.A. §§ 1424(a-c), 1427(f), 1451(c).
Proceeding under § 13(a) of this statute, the Attorney General, on November 22, 1950, petitioned the Board for an order directing petitioner to register pursuant to § 7 of the Act. Petitioner sought unsuccessfully by numerous motions before the Board and by proceedings in the United States District Court for the District of Columbia-one case is reported at 96 F.Supp. 47 (Communist Party of United States of America v. McGrath)-to attack the validity of, and to abort, the hearing. The hearing began on April 23, 1951, before three members of the Board, later reduced to two, sitting as a hearing panel, and it terminated on July 1, 1952. Proposed findings of fact and briefs were filed by both parties, and oral argument was held before the hearing panel in August 1952. In October 1952 the hearing panel issued a recommended decision that the Board order petitioner to register as a Communist-action organization. Exceptions to the panel's findings were filed by both parties, and oral argument was held before the Board in January 1953. The Board filed its report, which occupies 251 pages of the record in this case, on April 20, 1953.
In its report the Board found that there existed a world Communist movement, substantially as described in § 2 of the Act, organized and directed by a foreign government. The Board detailed the history of the Communist Party of the United States and its close relation to the world Communist movement. It then set forth illustrative evidence and made findings with respect to the statutory criteria of § 13(e) of the Act, which required the Board to consider 'the extent to which' the organization met them. The Board found that the conditions set forth in each of the paragraphs were applicable to petitioner. On the basis of these findings the Board concluded that petitioner was a Communist-action organization, as defined by § 3, and ordered it to register as such with the Attorney General.
Petitioner brought this order to the Court of Appeals for the District of Columbia for review. While the case was pending, it filed a motion, supported by affidavit, for leave to adduce additional evidence pursuant to § 14(a) of the Act. The basis of the motion was that the additional material evidence became available to the petitioner subsequent to the administrative proceeding and that this evidence would