After very extensive hearings under the Subversive Activities Control Act of 1950, the Board in 1953 found that the Communist Party of the United States was a "Communist-action organization," within the meaning of the Act, and ordered it to register as such under 7. A remand of the case by this Court, 351 U.S. 115, and a second remand by the Court of Appeals led to further proceedings before the Board, involving rulings on additional procedural points and two reconsiderations of the entire record, following which the Board adhered to its conclusion. After denial of motions made by the Party under 14 (a) and after review on the merits, the Court of Appeals affirmed the Boards order. Held: The judgment is affirmed. Pp. 4-115.

1. Certain procedural rulings made by the Board and the Court of Appeals do not constitute prejudicial errors requiring that this proceeding be remanded to the Board again. Pp. 22-35.

(a) A witness having been cross-examined at length following his direct testimony during the initial hearing, and the Board having stricken his testimony on two su