Appellee, a member of the Communist Party (which had been ordered to register as a Communist-action organization under the Subversive Activities Control Act) remained an employee at a shipyard after the Secretary of Defense had designated it a "defense facility" under the Act. Petitioner was thereafter indicted under § 5(a)(1)(D) of the Act for having "unlawfully and willfully engage[d]" in employment at the shipyard with knowledge of the outstanding order against the Party and of the notice of the Secretary's designation. The District Court, relying on Scales v. United States, 367 U. S. 203, dismissed the indictment for failure to allege that appellee was an active Party member with knowledge of and a specific intent to advance its unlawful purposes. The case was appealed to the Court of Appeals and then certified to this Court as a direct appeal.
Held: Section 5(a)(1)(D) is invalid since, by its overbreadth, it unconstitutionally abridges the right of association protected by the First Amendment. Pp. 389 U. S. 262-268.
(a) The indiscriminate application of § 5(a)(1)(D) to all types of association with Communist-action groups, regardless of the quality and degree of membership, makes it impossible by limiting construction to save the provision from constitutional infirmity. Cf. Aptheker v. Secretary of State, 378 U. S. 500. P. 389 U. S. 262.
(b) An individual's associational rights under the First Amendment are no less basic than the right to travel involved in Aptheker. Pp. 389 U. S. 262-263.
(c) The fact that the Act was passed pursuant to Congress' "war power" to further the "national defense" cannot "remove constitutional limitations safeguarding essential liberties," Home Bldg. & Loan Assn. v. Blaisdell, 290 U. S. 398, 290 U. S. 426. Pp. 389 U. S. 263-264.
(d) The statute literally establishes guilt by association alone, without any need to show that an individual's association poses the threat of sabotage and espionage in defense plants at which the legislation is directed. P. 389 U. S. 265.
Page 389 U. S. 259
(e) Section 5(a)(1)(D) includes within its coverage not only association which may be proscribed consistently with the First Amendment, but also association (such as that of passive members of a designated organization, those unaware of or disagreeing with its unlawful aims, and those in nonsensitive jobs at defense facilities) which cannot be so proscribed. Pp. 389 U. S. 265-266.
(f) Congress, in exercising its ample power to safeguard the national defense, cannot exceed constitutional bounds, particularly where First Amendment rights are at stake. Pp. 389 U. S. 266-268.