concurring in the result.
I too agree that the judgment of the District Court should be affirmed but I reach that result for different reasons.
Like the Court, I disagree with the District Court that §5(a)(l)(D) can be read to apply only to active members who have the specific intent to further the Party’s unlawful objectives. In Aptheker v. Secretary of State, 378 U. S. 500, we rejected that reading of § 6 of the Act which provides that, when a Communist organization is registered or under final order to register, it shall be unlawful for any member thereof with knowledge or notice of the order to apply for or use a passport. We held that “[t]he clarity and preciseness of the provision in question make it impossible to narrow its indiscriminately cast and overly broad scope without substantial rewriting.” 378 U. S., at 515. I take the same view of § 5 (a)(1)(D).
Aptheker held § 6 of the Act overbroad in that it deprived Party members of the right to travel without regard to whether they were active members of the Party or intended to further the Party’s unlawful objectives, and therefore invalidly abridged, on the basis of political associations, the members’ constitutionally protected right to travel. Section 5 (a)(1)(D) also treats as irrelevant whether or not the members are active, or know the Party’s unlawful purposes, or intend to pursue those purposes. Compare Keyishian v. Board of Regents, 385 U. S. 589; Elfbrandt v. Russell, 384 U. S. 11, 17; Scales v. United States, 367 U. S. 203; Schneiderman v. United States, 320 U. S. 118, 136. Indeed, a member such as appellee, who has worked at the Todd Shipyards without complaint or known ground for suspicion for over 10 years, is afforded no opportunity to prove that the statute’s presumption that he is a security risk is invalid as applied to him. And no importance whatever is attached to the sensitivity of the jobs held by Party mem*270bers, a factor long considered relevant in security cases.1 Furthermore, like §6, §5 (a)(1)(D) affects constitutionally protected rights. “[T]he right to hold specific private employment and to follow a chosen profession free from unreasonable governmental interference comes within the ‘liberty’ and ‘property’ concepts of the Fifth Amendment . . . .” Greene v. McElroy, 360 U. S. 474, 492. That right is therefore also included among the “[individual liberties fundamental to American institutions [which] are not to be destroyed under pretext of preserving those institutions, even from the gravest external dangers.” Communist Party v. Subversive Activities Control Board, 367 U. S. 1, 96. Since employment opportunities are denied by §5 (a)(1)(D) simply on the basis of political associations the statute also has the potential of curtailing free expression by inhibiting persons from establishing or retaining such associations. See Wieman v. Updegraff, 344 U. S. 183, 191. “Broad prophylactic rules in the area of free expression are suspect. . . . Precision of regulation must be the touchstone in . . . area[s] so closely touching our most precious freedoms.” NAACP v. Button, 371 U. S. 415, 438; see Shelton v. Tucker, 364 U. S. 479, 488; Cantwell v. Connecticut, 310 U. S. 296, 304.
It is true, however, as the Government points out, that Congress often regulates indiscriminately, through preventive or prophylactic measures, e. g., Board of Governors v. Agnew, 329 U. S. 441; North American Co. v. SEC, 327 U. S. 686, and that such regulation has been upheld even where fundamental freedoms are potentially affected, Hirabayashi v. United States, 320 U. S. 81 ; *271Cafeteria Workers v. McElroy, 367 U. S. 886; Carlson v. Landon, 342 U. S. 524. Each regulation must be examined in terms of its potential impact upon fundamental rights, the importance of the end sought and the necessity for the means adopted. The Government argues that §5 (a)(1)(D) may be distinguished from § 6 on the basis of these factors. Section 5 (a)(1)(D) limits employment only in “any defense facility,” while § 6 deprived every Party member of the right to apply for or to hold a passport. If § 5 (a)(1)(D) were in fact narrowly applied, the restrictions it would place upon employment are not as great as those placed upon the right to travel by § 6.2 The problems presented by the employment of Party members at defense facilities, moreover, may well involve greater hazards to national security than those created by allowing Party members to travel abroad. We may assume, too, that Congress may have been justified in its conclusion that alternatives to § 5 (a)(1)(D) were inadequate.3 For these reasons, *272I am not persuaded to the Court’s view that overbreadth is fatal to this statute, as I agreed it was in other contexts; see, e. g., Keyishian v. Board of Regents, 385 U. S. 589; Elfbrandt v. Russell, 384 U. S. 11; Aptheker v. Secretary of State, 378 U. S. 500; NAACP v. Button, 371 U. S. 415.
However, acceptance of the validity of these distinctions and recognition of congressional power to utilize a prophylactic device such as §5 (a)(1)(D) to safeguard against espionage and sabotage at essential defense facilities, would not end inquiry in this case. Even if the statute is not overbroad on its face — because there may be “defense facilities” so essential to our national security that Congress could constitutionally exclude all Party members from employment in them — the congressional delegation of authority to the Secretary of Defense to designate “defense facilities” creates the danger of overbroad, unauthorized, and arbitrary application of criminal sanctions in an area of protected freedoms and therefore, in my view, renders this statute invalid. Because the statute contains no meaningful standard by which the Secretary is to govern his desig*273nations, and no procedures to contest or review his designations, the “defense facility” formulation is constitutionally insufficient to mark “the field within which the [Secretary] is to act so that it may be known whether he has kept within it in compliance with the legislative will.” Yakus v. United States, 321 U. S. 414, 425.
The Secretary’s role in designating “defense facilities” is fundamental to the potential breadth of the statute, since the greater the number and types of facilities designated, the greater is the indiscriminate denial of job opportunities, under threat of criminal punishment, to Party members because of their political associations. A clear, manageable standard might have been a significant limitation upon the Secretary’s discretion. But the standard under which Congress delegated the designating power is so indefinite as to be meaningless. The statute defines “facility” broadly enough to include virtually every place of employment in the United States; the term includes “any plant, factory or other manufacturing, producing or service establishment, airport, airport facility, vessel, pier, water-front facility, mine, railroad, public utility, laboratory, station, or other establishment or facility, or any part, division, or department of any of the foregoing.” 50 U. S. C. § 782 (7). And § 5 (b) grants the Secretary of Defense untrammelled discretion to designate as a “defense facility” any facility “with respect to the operation of which he finds and determines that the security of the United States requires . . .” that Party members should not be employed there. Congress could easily have been more specific.4 Instead, Congress left the Secretary completely *274at large in determining the relevance and weight to be accorded such factors as the importance and secrecy of the facility and of the work being done there, and the indispensability of the facility’s service or product to the' national security.
Congress ordinarily may delegate power under broad standards. E. g., Dakota Central Tel. Co. v. South Dakota, 250 U. S. 163, 183; FPC v. Hope Natural Gas Co., 320 U. S. 591; NBC v. United States, 319 U. S. 190. No other general rule would be feasible or desirable. Delegation of power under general directives is an inevitable consequence of our complex society, with its myriad, ever changing, highly technical problems. “The Constitution has never been regarded as denying to the Congress the necessary resources of flexibility and practicality ... to perform its function . . . .” Panama Refining Co. v. Ryan, 293 U. S. 388, 421; Currin v. Wallace, 306 U. S. 1, 15. It is generally enough that, in conferring power upon an appropriate authority, Congress *275indicate its general policy, and act in terms or within a context which limits the power conferred. See, e. g., Arizona v. California, 373 U. S. 546, 584-585; FCC v. RCA Communications, Inc., 346 U. S. 86; Lichter v. United States, 334 U. S. 742; Yakus v. United States, supra, at 424; Bandini Petroleum Co. v. Superior Court, 284 U. S. 8; FTC v. Gratz, 253 U. S. 421; Buttfield v. Stranahan, 192 U. S. 470. Given such a situation, it is possible for affected persons, within the procedural structure usually established for the purpose, to be heard by the implementing agency and to secure meaningful review of its action in the courts, and for Congress itself to review its agent’s action to correct significant departures from Congress’ intention.
The area of permissible indefiniteness narrows, however, when the regulation invokes criminal sanctions and potentially affects fundamental rights, as does §5 (a)(1)(D). See Barenblatt v. United States, 360 U. S. 109, 140, n. 7 (Black, J., dissenting). This is because the numerous deficiencies connected with vague legislative directives, whether to a legislative committee, United States v. Rumely, 345 U. S. 41; to an executive officer, Panama Refining Co. v. Ryan, 293 U. S. 388; to a judge and jury, Cline v. Frink Dairy Co., 274 U. S. 445, 465; or to private persons, Bantam Books, Inc. v. Sullivan, 372 U. S. 58; see Schechter Poultry Corp. v. United States, 295 U. S. 495; are far more serious when liberty and the exercise of fundamental rights are at stake. See also Gojack v. United States, 384 U. S. 702; Kunz v. New York, 340 U. S. 290; Winters v. New York, 333 U. S. 507; Thornhill v. Alabama, 310 U. S. 88; Hague v. CIO, 307 U. S. 496; Herndon v. Lowry, 301 U. S. 242.
First. The failure to provide adequate standards in §5 (a)(1)(D) reflects Congress’ failure to have made a “legislative judgment,” Cantwell v. Connecticut, 310 *276U. S., at 307, on the extent to which the prophylactic measure should be applied. Formulation of policy is a legislature’s primary responsibility, entrusted to it by the electorate, and to the extent Congress delegates authority under indefinite standards, this policy-making function is passed on to other agencies, often not answerable or responsive in the same degree to the people. “[Standards of permissible statutory vagueness are strict . . .” in protected areas. NAACP v. Button, 371 U. S., at 432. “Without explicit action by lawmakers, decisions of great constitutional import and effect would be relegated by default to administrators who, under our system of government, are not endowed with authority to decide them.” Greene v. McElroy, 360 U. S. 474, 507.
Congress has the resources and the power to inform itself, and is the appropriate forum where the conflicting pros and cons should have been presented and considered. But instead of a determination by Congress reflected in guiding standards of the types of facilities to which §5 (a)(1)(D) should be applied, the statute provides for a resolution by the Secretary of Defense acting on his own accord. It is true that the Secretary presumably has at his disposal the information and expertise necessary to make reasoned judgments on which facilities are important to national security. But that is not the question to be resolved under this statute. Compare Hague v. CIO, 307 U. S. 496. Rather, the Secretary is in effect determining which facilities are so important to the national security that Party members, active or inactive, well- or ill-intentioned, should be prohibited from working within them in any capacity, sensitive or innocuous, under threat of criminal prosecution. In resolving this conflict of interests, the Secretary’s judgment, colored by his overriding obligation to protect the national defense, is not *277a constitutionally acceptable substitute for Congress’ judgment, in the absence of further, limiting guidance.5
The need for a legislative judgment is especially acute here, since it is imperative when liberty and the exercise of fundamental freedoms are involved that constitutional rights not be unduly infringed. Cantwell v. Connecticut, supra, at 304. Before we can decide whether it is an undue infringement of protected rights to send a person to prison for holding employment at a certain type of facility, it ought at least to appear that Congress authorized the proscription as warranted and necessary. Such congressional determinations will not be assumed. “They must be made explicitly not only to assure that individuals are not deprived of cherished rights under procedures not actually authorized . . . but also because explicit action, especially in areas of doubtful constitutionality, requires careful and purposeful consideration by those responsible for enacting and implementing our laws.” Greene v. McElroy, supra, at 507.
Second. We said in Watkins v. United States, 354 U. S. 178, 205, that Congress must take steps to assure “respect *278for constitutional liberties” by preventing the existence of “a wide gulf between the responsibility for the use of . . . power and the actual exercise of that power.” Procedural protections to avoid that gulf have been recognized' as essential when fundamental freedoms are regulated, Speiser v. Randall, 357 U. S. 513; Marcus v. Search Warrant, 367 U. S. 717, 730; A Quantity of Copies of Books v. Kansas, 378 U. S. 205, 213; even when Congress acts pursuant to its “great powers,” Kennedy v. Mendoza-Martinez, 372 U. S. 144, 164. Without procedural safeguards, regulatory schemes will tend through their indiscriminate application to inhibit the activity involved. See Marcus v. Search Warrant, supra, at 734-735.
It is true that “[a] construction of the statute which would deny all opportunity for judicial determination of an asserted constitutional right is not to be favored.” Lockerty v. Phillips, 319 U. S. 182, 188. However, the text and history of this section compel the conclusion that Congress deliberately chose not to provide for protest either to the Secretary or the courts from any designation by the Secretary of a facility as a “defense facility.” The absence of any provision in this regard contrasts strongly with the care that Congress took to provide for the determination by the SACB that the Party is a Communist-action organization, and for judicial review of that determination. The Act “requires the registration only of organizations which . . . are found to be under the direction, domination, or control of certain foreign powers and to operate primarily to advance certain objectives. This finding must be made after full administrative hearing, subject to judicial review which opens the record for the reviewing court’s determination whether the administrative findings as to fact are supported by the preponderance of the evidence.” Communist Party v. Subversive Activities Control Board, *279supra, at 86-87. In contrast, the Act nowhere provides for an administrative-hearing on the Secretary’s designation, either public or private, nor is his finding subject to review. A Party member charged with notice of the designation must quit the Party or his job; he cannot contest the Secretary’s action on trial if he retains both and is prosecuted.6
This is persuasive evidence that the matter of the designation of “defense facilities” was purposely committed by Congress entirely to the discretionary judgment of the Secretary. Unlike the opportunities for hearing and judicial review afforded the Party itself, the Party member was not to be heard by the Secretary to protest the designation of his place of employment as a “defense facility,” nor was the member to have recourse to the courts. This pointed distinction, as in the case of the statute before the Court in Schilling v. Rogers, 363 U. S. 666, 674, is compelling evidence “that in this Act Congress was advertent to the role of courts, and an absence in any specific area of any kind of provision for judicial participation strongly indicates a legislative purpose that there be no such participation.” This clear indication of the congressional plan, coupled *280with a flexibility- — as regards the boundaries of the Secretary’s discretion — so unguided as to be entirely unguid-ing, must also mean that Congress contemplated that an affected Party member was not to be heard to contend even at his criminal trial that the Secretary acted beyond the scope of his powers, or that the designation of the particular facility was arbitrary and capricious. Cf. Estep v. United States, 327 U. S. 114.
The legislative history of the section confirms this conclusion. That history makes clear that Congress was concerned that neither the Secretary’s reasons for a designation nor the fact of the designation should be publicized. This emerged after President Truman vetoed the statute. In its original form the Act required the Secretary to “designate and proclaim, and from time to time revise, a list of facilities ... to be promptly published in the Federal Register . . . .” § 5 (b). The President commented in his veto message, “[s]pies and saboteurs would willingly spend years of effort seeking to find out the information that this bill would require the Government to hand them on a silver platter.” H. R. Doc. No. 708, 81st Cong., 2d Sess., 2 (1950). Shortly after this Court sustained the registration provisions of the Act in Communist Party v. Subversive Activities Control Board, supra, the Act was amended at the request of the Secretary to eliminate the requirement that the list of designated facilities be published in the Federal Register. 76 Stat. 91. Instead, the list is classified information. Whether or not such classification is practically meaningful — in light of the fact that notice of a designation must be posted in the designated facility— the history is persuasive against any congressional intention to provide for hearings or judicial review that might be attended with undesired publicity. We are therefore not free to imply limitations upon the Secretary’s discretion or procedural safeguards that Congress obviously *281chose to omit. Compare Cole v. Young, 351 U. S. 536; United States v. Rumely, supra; Ex parte Endo, 323 U. S. 283, 299; Japanese Immigrant Case, 189 U. S. 86, 101; see Greene v. McElroy, supra, at 507.
Third. The indefiniteness of the delegation in this case also results in inadequate notice to affected persons. Although the form of notice provided for in § 5 (b) affords affected persons reasonable opportunity to conform their behavior to avoid punishment, it is not enough that persons engaged in arguably protected activity be reasonably well advised that their actions are subject to regulation. Persons so engaged must not be compelled to conform their behavior to commands, no matter how unambiguous, from delegated agents whose authority to issue the commands is unclear. Marcus v. Search Warrant, supra, at 736. The legislative directive must delineate the scope of the agent’s authority so that those affected by the agent’s commands may know that his command is within his authority and is not his own arbitrary fiat. Cramp v. Board of Public Instruction, 368 U. S. 278; Scull v. Virginia, 359 U. S. 344; Watkins v. United States, supra, at 208-209. There is no way for persons affected by § 5 (a)(1)(D) to know whether the Secretary is acting within his authority, and therefore no fair basis upon which they may determine whether or not to risk disobedience in the exercise of activities normally protected.
Section 5(a)(1)(D) denies significant employment rights under threat of criminal punishment to persons simply because of their political associations. The Government makes no claim that Robel is a security risk. He has worked as a machinist at the shipyards for many years, and we are told is working there now. We are in effect invited by the Government to assume that Robel is a law abiding citizen, earning a living at his chosen trade. The justification urged for punishing him is that *282Congress may properly conclude that members of the Communist Party, even though nominal or inactive members and believing only in change through lawful means, are more likely than other citizens to engage in acts of espionage and sabotage harmful to our national security. This may be so. But in areas of protected freedoms, regulation based upon mere association and not upon proof of misconduct or even of intention to act unlawfully, must at least be accompanied by standards or procedural protections sufficient to safeguard against indiscriminate application. “If . . . ‘liberty’ is to be regulated, it must be pursuant to the law-making functions of the Congress . . . [a]nd if that power is delegated, the standards must be adequate to pass scrutiny by the accepted tests.” Kent v. Dulles, 357 U. S. 116, 129.
See Cole v. Young, 351 U. S. 536, 546:
“[I]t is difficult to justify summary suspensions and unreviewable dismissals on loyalty grounds of employees who are not in ‘sensitive’ positions and who are thus not situated where they could bring about any discernible adverse effects on the Nation’s security.”
The Government also points out that § 5 (a) (1) (D) applies only to members of “Communist-action” organizations, while § 6 applied also to members of “Communist-front” organizations, groups which the Government contends are less dangerous to the national security under Congress’ definitions, and whose members are therefore presumably less dangerous. This distinction is, however, open to some doubt. Even if a “front” organization, which is defined as an organization either dominated by or primarily operated for the purpose of aiding and supporting “action” organizations, could in some fashion be regarded as less dangerous, Aptheker held § 6 invalid because it failed to discriminate among affected persons on the bases of their activity and commitment to unlawful purposes, and nothing in the opinion indicates the result would have been different if Congress had been indiscriminate in these respects with regard only to “Communist-action” group members.
The choice of a prophylactic measure “must be viewed in the light of less drastic means for achieving the same basic purpose.” Shelton v. Tucker, 364 U. S. 479, 488. Since I would affirm on another ground, however, I put aside the question whether existing *272security programs were inadequate to prevent serious, possibly catastrophic consequences.
Congress rejected suggestions of the President and the Department of Justice that existing security programs were adequate with only slight modifications. See H. R. Doc. No. 679, 81st Cong., 2d Sess., 5 (1950); Hearings on Legislation to Outlaw Certain Un-American and Subversive Activities before the House Un-American Activities Committee, 81st Cong., 2d Sess., 2122-2125 (1950). Those programs cover most of the facilities within the reach of § 5 (a)(1)(D) and make Party membership an important factor governing access. 32 CFR § 155.5. They provide measures to prevent and punish subversive acts. The Department of Defense, moreover, had screened some 3,000,000 defense contractor employees under these procedures by 1956, Brown, Loyalty and Security 179-180 (1958), thereby providing at least some evidence of its capacity to handle this problem in a more discriminating manner.
Congress, in fact, originally proposed to limit the Secretary’s discretion in designating “defense facilities.” H. R. 9490, passed by both the House and Senate, provided that the Secretary should determine and designate each “defense plant” as defined in § 3 (7) of the Act. The difference between that version and § 5 (a) (1) (D) *274adopted at conference is commented upon in H. R. Conf. Rep. No. 3112, 81st Cong., 2d Sess., 50 (1950):
“Under section 3 (7) a defense plant was defined as any plant, factory, or other manufacturing or service establishment, or any part thereof, engaged in the production or furnishing, for the use of the Government of any commodity or service determined and designated by the Secretary of Defense to be of such character as to affect the military security of the United States.
“Section 3 (7), and the provisions of section 5 relating to the designation of defense plants by the Secretary of Defense, have been modified in the conference substitute so as to broaden the concept of defense plants to cover any appropriately designated plant, factory or other manufacturing, producing, or service establishment, airport, airport facility, vessel, pier, water-front facility, mine, railroad, public utility, laboratory, station, or other establishment or facility, or any part, division, or department of any of the foregoing. Because of this broader coverage, section 3 (7) has been changed so as to define the two terms 'facility’ and ‘defense facility.’ ”
The Secretary has published criteria which guide him in applying the statute:
“The list of ‘defense facilities’ is comprised of (1) facilities engaged in important classified military projects; (2) facilities producing important weapons systems, subassemblies and their components; (3) facilities producing essential common components, intermediates, basic materials and raw materials; (4) important utility and service facilities; and (5) research laboratories whose contributions are important to the national defense. The list, which will be amended from time to time as necessary, has been classified for reasons of security.”
Department of Defense Release No. 1363-62, Aug. 20, 1962. These broad standards, which might easily justify applying the statute to most of our major industries, cannot be read into the statute to limit the Secretary’s discretion, since they are subject to unreviewable amendment.
The statute contemplates only four significant findings before criminal liability attaches: (1) that the Communist Party is a “Communist-action organization”; (2) that defendant is a member of the Communist Party; (3) that defendant is engaged in employment at a “defense facility”; and (4) that he had notice that his place of employment was a “defense facility.” The first finding was made by the Subversive Activities Control Board. The third finding — that the shipyard is a “defense facility” — was made by the Secretary of Defense. The fourth finding refers to the notice requirement which is no more than a presumption from the posting required of the employer by §5 (b). Thus the only issue which a defendant can effectively contest is whether he is a Communist Party member. In view of the result which I would reach, however, I need not consider appellee’s argument that this affords defendants only the shadow of a trial, and violates due process.