whom Mr. Justice Brennan joins, dissenting.
This litigation began with a comprehensive constitutional attack by appellants on longstanding state rules and practices for screening applicants for admission to the New York Bar.1 During the course of the litigation *186some of these practices were changed by appellees; others were found wanting by the three-judge court below, and changed as a result of that court’s opinion and its final order. Now we face the residuum of the appellants’ original challenge, and the Court today ratifies everything left standing by the court below. I dissent from that holding because I believe that appellants’ basic First Amendment complaint, transcending the particulars of the attack, retains its validity. The underlying complaint, strenuously and consistently urged, is that New York’s screening system focuses impermissibly on the political activities and viewpoints of Bar applicants, that the scheme thereby operates to inhibit the exercise of protected expressive and associational freedoms by law students and others, and that this chilling effect is not justified as the necessary impact of a system designed to winnow out those applicants demonstrably unfit to practice law.
As an abstract matter I do not take issue with the proposition that some inquiry into the qualifications of Bar applicants may be made, beyond such obvious threshold qualifications as residence or success in a regularly administered written examination. Accordingly, I would not upset the general rules which charter an inquiry as to the “fitness” of applicants, absent a showing not made here, that in practice the general rules work an impermissible result. But this is hardly the end of the case. For New York is not content with a politically neutral investigation into the fitness of Bar applicants to practice law. Screening officials are specifically directed by state law to assess an applicant’s political beliefs and loyalties, and to scrutinize his associational and other political activities for signs that the applicant holds certain viewpoints. Such an inquiry, in my view, flatly offends the First Amendment, and state laws or adminis*187trative rules that license such an inquiry must be struck down.
Rule 9406 of the New York Civil Practice Law and Rules prescribes: “No person . . . shall be admitted to practice . . . unless he shall furnish satisfactory proof to the effect . . . that he believes in the form of the government of the United States and is loyal to such government . . . .”2 The Court rightly notes that Rule 9406 is addressed to the appellees, that is, to the investigating committees which pass in the first instance on applications for admission, and also to the relevant judicial department of the Appellate Division of the New York Supreme Court. Appellees, pursuant to Rule 9406, require Bar applicants to answer a questionnaire now containing two questions designed to uncover information about an applicant’s political loyalties and associational affiliations. Question 27,3 set forth in the margin, is one natural consequence of Rule 9406 — part (b) of Question 27 commands an applicant to tell whether he is “without any mental reservation, loyal to and ready to support the Constitution.” Question 264 requires an *188applicant to “state the facts” concerning his affiliation with any organization which he knew to advocate political change “by force, violence or any unlawful means.” Under the scheme set in operation by Rule 9406, ap-pellees’ job is to evaluate all the information turned up by the questionnaire, by required affidavits, by a personal interview with the applicant, and by other means, and then to determine whether an applicant has made “satisfactory proof” of the specified political beliefs and loyalties.
I have no doubt whatever that Rule 9406, if read to mean what it says, must fall as violative of settled constitutional principles, or that any inquisition designed to implement a rule so written must equally be barred. Rule 9406 directs screening officials to probe the contents of an individual’s political philosophy in order to ascertain whether he entertains certain beliefs as a matter of personal faith. The Rule, which charters an inquisition, fastens, not upon overt conduct, nor even on activities that incidentally involve the public exposure or advocacy of ideas, but on personal belief itself. Yet it is a settled principle of our constitutional order that, whatever may be the limits of the freedom to act on one’s convictions, the freedom to believe what one will “is absolute.” Cantwell v. Connecticut, 310 U. S. 296, 303 (1940). As we said not long ago in Stanley v. Georgia, 394 U. S. 557, 565 (1969), “Our whole constitutional heritage rebels at the thought of giving government the power to control men’s minds.” The premise that personal beliefs are inviolate is fundamental to the constitutional scheme as a whole, see Olmstead v. United States, 277 U. S. 438, 478 (1928) (Brandeis, J., dis*189senting), and the premise is not questioned even in cases where this Court has divided sharply over the extent of the First Amendment's protections. See, e. g., American Communications Assn. v. Douds, 339 U. S. 382, 412 (1950) (Vinson, C. J., for the Court), and id., at 446-448 (Black, J., dissenting). In the present case we have a rule of New York law which, as written, sanctions systematic inquiry into the beliefs of Bar applicants, and excludes from the practice of law persons having beliefs that are not officially approved.5 This inquiry and this criterion for exclusion are impermissible. However wayward or unorthodox a man’s political beliefs may be, he may not be kept out or drummed out of the Bar or any other profession on that account.
The Court purports not to uphold — not to pass upon- — Rule 9406 unvarnished. While conceding that the Rule, as it has been written, is constitutionally problematical, the Court asserts that it should be judged in light of the “extremely narrow” interpretation proffered by appellees, who are charged with administering the investigatory scheme contemplated by the Rule. According to the proposed administrative construction, Rule 9406 merely directs appellees to discover whether a Bar applicant is willing and able to promise that he will support the Constitutions of the United States and the State of New York. An oath promising support for the Federal and State Constitutions is required of persons *190admitted to the practice of law in New York, as of state officers generally.6 The Court’s argument, then, is that since the “support” oath may validly be required, see Knight v. Board of Regents, 269 F. Supp. 339 (SDNY 1967), aff’d per curiam, 390 U. S. 36 (1968), it is permissible for appellees to inquire into the willingness and the ability of applicants to take the support oath in full honesty and good faith — further, that since Rule 9406 has been “construed” to sanction no more than such an inquiry into applicants’ sincerity, the Rule and the whole investigatory scheme of the Rule should be upheld.
There are several flaws in the Court’s analysis. We are told that while the Rule may be too sweeping, the administrative construction is narrow enough, so the construction saves the Rule. But this argument cannot merit embrace unless, in the first instance, we are able to ascertain the meaning and the sweep of the administrative interpretation itself. The majority opinion points to no New York case law that shows what the proffered interpretation means. Nor, I think, can the Court comfortably point to appellees’ past practice as a guide to the proper interpretation of Rule 9406. For the opinions below and the papers in this case reveal that these appellees, prior to the launching of this litigation, thought it their duty to make virtually unlimited inquiry into an applicant’s associational, political, and journalistic activities7 Thus past administrative practice, which may *191sometimes be helpful in clarifying the sweep of a doubtful law, cf. Fox v. Standard Oil Co., 294 U. S. 87, 96-97 (1935), in this case is no help at all in settling constitutional doubts concerning the reach of Rule 9406. Ap-pellees’ announcement that they will be more restrained, and will focus their inquiries on “sincerity,” is of course entitled to the full respect of a reviewing court. Nonetheless, I do not believe that Rule 9406 is saved by the announcement. At any rate, we certainly are not confronted by “long usage” giving “well-defined contours,” see ante, at 159, to appellees’ proposed construction of the challenged Rule.
A second defect of the Court’s analysis is that any attempt to assimilate Rule 9406 to the “support” oath, for First Amendment purposes, must fail. The majority urges such an assimilation on the theory that “ ‘the form of the government of the United States’ and the ‘govern*192ment’ [terms of Rule 9406] refer solely to the Constitution, which is all that the oath mentions.” Yet as Mr. Justice Black’s dissent today makes clear, the oath of constitutional support is promissory and forward looking in nature, while the focus of the challenged Rule is quite different. The oath of constitutional support requires an individual assuming public responsibilities to affirm, in entirely familiar and traditional language,8 that he will endeavor to perform his public duties lawfully. This is a far cry from Rule 9406, or Question 27 (b) of ap-pellees’ questionnaires, both of which are designed to probe the personal political philosophy that an applicant entertains, his beliefs and loyalties and even his “mental reservations.” To require the traditional oath of constitutional support does not put government in the censorial business of investigating, scrutinizing, interpreting, and then penalizing or approving the political viewpoints of individuals. For that reason the validity of the support oath is sui generis, and does not serve to justify the investigatory scheme set up by Rule 9406.
Surely it is a mistake to conclude that because a State may administer a support oath, it may therefore conduct an investigation into the beliefs and affiliations of Bar applicants in order to gauge the depth of their “willingness to take the constitutional oath and ability to do so in good faith.” The seeming logic of this position was flatly repudiated in Bond v. Floyd, 385 U. S. 116 (1966). In that case the Court confronted the record of an actual inquiry into the “sincerity” of a prospective oath taker, and the inquiry was found to be an impermissible encroachment on First Amendment freedoms. The Court noted that the power “to test the sincerity” of a person who must take an oath of constitutional support “could be utilized to restrict the right ... to dissent from na*193tional or state policy . . . under the guise of judging . . . loyalty to the Constitution.” Id,., at 132.9 This is the very power which appellees claim under what the Court calls an “extremely narrow” construction of Rule 9406. It is a power of uncertain and dangerous dimension, and patently susceptible of censorial abuses.
For me the conclusion is inescapable that appellees’ construction, far from saving Rule 9406, actually compounds its constitutional defects. The original vice of the Rule remains. State screening officials still are licensed to investigate an applicant’s political activities and affiliations, and to probe his beliefs and loyalties and “mental reservations” — all this supposedly for the sake of protecting the integrity of the oath of constitutional support. The professed rationale of the enterprise may have been refurbished, but the search for true belief and unreserved loyalty remains. So construed, Rule 9406 is plainly overbroad. It sanctions overreaching *194official inquiries. It is impermissibly sweeping as a criterion for exclusion from the Bar. The Rule as interpreted suffers from the very defects that this Court has found fatal to other schemes that have sought to predicate the grant or denial of public benefits on a person’s political affiliations and viewpoints. See, e. g., United States v. Robel, 389 U. S. 258 (1967); Keyishian v. Board of Regents, 385 U. S. 589 (1967); cf. Schneider v. Smith, 390 U. S. 17 (1968).
Appellees’ gloss compounds the defects of the Rule, in my view, because the proffered interpretation is vague in the extreme. It is of course conceivable that an inquiry into a Bar applicant’s “sincerity” might be quite simple and definite in scope. Appellees suggest in the Motion to Affirm that some inquiry might be useful “to avoid the difficulty of having one individual demur to the taking of [the support] oath at the very moment prior to admission.” But this limited objective of avoiding an embarrassing disruption of the admission ceremony is adequately handled by Question 27 (a), as drafted by the District Court. Plainly, appellees have a'good deal more in mind, as is shown by their insistence that Question 26 and Question 27 (b) aid in determining an applicant’s “sincerity.” These are the questions that focus on beliefs, loyalties, and affiliations. I cannot say that a Bar applicant, a law student, or anyone else is given fair warning as to the kind of political activities and affiliations that appellees mean to penalize as evidencing “insincerity.” Thus, in my view, Rule 9406, as construed, is fatally vague. Standards of definiteness must be strict as to legal rules which trench on First Amendment activities. NAACP v. Button, 371 U. S. 415, 432-433 (1963). See United States v. National Dairy Corp., 372 U. S. 29, 36 (1963). The irreducible vices of due process vagueness, arising when those who *195may be penalized by a legal rule cannot ascertain the rule’s scope and avoid its burdens, see Lanzetta v. New Jersey, 306 U. S. 451, 453 (1939), are inevitably heightened when the result is deterrence of protected activity. Cramp v. Board of Public Instruction, 368 U. S. 278, 287-288 (1961). Appellants’ fundamental complaint throughout this litigation has concerned the inhibitory impact of New York’s screening system on the exercise of First Amendment rights. I agree that the chilling effect of Rule 9406, as construed, is exacerbated by the sort of vagueness that this Court has condemned on a number of hardly distinguishable occasions. See, e. g., Whitehill v. Elkins, 389 U. S. 54 (1967); Keyishian v. Board of Regents, supra; Dombrowski v. Pfister, 380 U. S. 479 (1965); Baggett v. Bullitt, 377 U. S. 360 (1964); Cramp v. Board of Public Instruction, supra.
A further word is required concerning the validity of Question 26 of appellees’ questionnaire. The Court expressly approves Question 26, but fails to consider the relationship of the question to Rule 9406 itself, beyond noting that Question 26 “reflects” the Rule’s command that an applicant’s beliefs and loyalties be investigated. I believe it is a mistake to consider the question entirely in isolation from the investigatory scheme set up by the Rule. See Whitehill v. Elkins, supra, at 56-57 (“we must consider the oath with reference to [related provisions concerning subversives], not in isolation”). Question 26 is undeniably a key part of that scheme. The District Court saw Rule 9406 as an instruction to screening officials “to satisfy themselves through analysis of the factual data before them” that an applicant has requisite beliefs and loyalties. See 299 F. Supp., at 126. Question 26 is a potent device for uncovering “factual data” about an applicant’s associational affiliations.
*196Question 26 (a) asks whether the applicant has “ever organized or helped to organize or become a member of” any association that he knew was “advocating or teaching” that any local, state, or federal governmental institution “should be overthrown or overturned by force, violence or any unlawful means.” Plainly this language covers a wide range of associational activities fully protected by the First Amendment, along with some conduct that may not be privileged. The question is not aimed at concerted activity of whatever sort oriented to the doing of illegal acts, but at affiliations with political associations that “advocate” or “teach” certain political ideas. All kinds and degrees of affiliation are covered: indifferent and energetic members alike, in well-disciplined organizations or in any transitory “group of persons.” There is no specificity in the phrase, “overthrown or overturned by force, violence or any unlawful means.” The language covers all advocacy of thoroughgoing political change to be brought about partly through unlawful acts — acts to be done now, or at some hypothetical future moment which may or may not occur — acts of bloody and atrocious terror, or conscientious action involving nonviolent disobedience to law. “Advocating or teaching” includes the most abstract sort of doctrinal discourse, and ideological utterances altogether ancillary to the political program of a given association.
Even when viewed in isolation from Rule 9406, Question 26 (a) reveals itself as an indiscriminate and highly intrusive device designed to expose an applicant’s political affiliations to the scrutiny of screening authorities. As such, it comes into conflict with principles that bar overreaching official inquiry undertaken with a view to predicating the denial of a public benefit on activity pro*197tected by the First Amendment.10 Three particular difficulties may be mentioned. First, Question 26 (a) is undeniably overbroad in that it covers the affiliations of those who do not adhere to teachings concerning unlawful political change, or are simply indifferent to this aspect of an association’s activities. Elfbrandt v. Russell, 384 U. S. 11, 16-19 (1966); Aptheker v. Secretary of State, 378 U. S. 500, 510-512 (1964). Second, no attempt has been made to limit Question 26 (a) to associational advocacy of concrete, specific, and imminent illegal acts, or to associational activity that creates a serious likelihood of harm through imminent illegal conduct. See Brandenburg v. Ohio, 395 U. S. 444, 447-449; *198Keyishian v. Board of Regents, 385 U. S., at 599-601. Third, would-be Bar applicants are left to wonder whether particular political acts amount to “becom[ing] a member” of a “group of persons” — law students and others, when embarking on associational activities, must guess whether the association’s teachings fall within the nebulous formula of Question 26 (a), or, more to the point, whether their own assessment of an association’s teachings would coincide with that of screening officials. There are penalties for failing to “state the facts” required by Question 26 (a) when the time to make application comes. The indefinite scope of Question 26 (a) expectedly operates to induce prospective applicants to resolve doubts by failing to exercise their First Amendment rights. See Dombrowski v. Pfister, 380 U. S., at 493-494; Baggett v. Bullitt, 377 U. S., at 367-370.
But whatever may be thought of Question 26 or either of its two parts standing alone,11 it remains that the function of the question is to generate “factual data” about an applicant’s political affiliations and activities to be judged ultimately by the operative standards of Rule *1999406. Doubts concerning the propriety of the question are intensified when the question is viewed realistically as part of the investigatory scheme set up by the Rule. Cf. Whitehill v. Elkins, 389 U. S. 54 (1967). In “stat[ing] the facts” as required by Question 26, an applicant exposes himself to the grave risk that screening officials will find him wanting in respect of the requisite beliefs and loyalties. The impermissible latitude of Rule 9406 as a criterion for exclusion, in conjunction with overintru-sive probing for details about an applicant’s associational affiliations, creates an obvious in terrorem effect on the exercise of First Amendment freedoms by law students and others. The interwoven complexity and uncertain scope of the scheme heighten the danger that caution and conscientiousness will lead to the forfeiting of rights by prospective Bar applicants. See Keyishian v. Board of Regents, supra, at 604. Appellees’ attempt to save the whole scheme by restrictive construction of the Rule amounts, in my view, to little more than a declaration of beneficent intent, and we have said that good intentions “do not neutralize the vice” of vagueness and over-breadth. Baggett v. Bullitt, supra, at 373. The valid aims of appellees’ screening efforts can be achieved without casting a pall on protected activity. But Question 26, viewed in light of Rule 9406, overreaches legitimate concerns and places an impermissible burden on the exercise of fundamental rights.
For the reasons stated I would strike down the portions of Rule 9406 discussed herein, as written and construed, and also Questions 26 and 27 (b). To that extent I would reverse the District Court.
The attack is upon rules of statewide application and practices administered by appellees in the First and Second Judicial Departments.
The full text of Rule 9406 is printed, ante, at 169.
“27. (a) Is there any reason why you cannot take and subscribe to an oath or affirmation that you will support the constitutions of the United States and of the State of New York? If there is, please explain.
“(b) Can you conscientiously, and do you, affirm that you are, without any mental reservation, loyal to and ready to support the Constitution of the United States?”
“26. (a) Have you ever organized or helped to organize or become a member of any organization or group of persons which, during the period of your membership or association, you knew was advocating or teaching that the government of the United States or any state or any political subdivision thereof should be overthrown or overturned by force, violence or any unlawful means? -.
If your answer is in the affirmative, state the facts below.
“(b) If your answer to (a) is in the affirmative, did you, during the period of such membership or association, have the specific *188intent to further the aims of such organization or group of persons to overthrow or overturn the government of the United States or any state or any political subdivision thereof by force, violence or any unlawful means?”
In addition to the defects mentioned at text, Rule 9406, as written, violates the principle of Speiser v. Randall, 357 U. S. 513 (1958). Rule 9406 provides that “no person shall be admitted” to the New York Bar “unless he shall furnish satisfactory proof” of required beliefs and loyalties. Speiser condemns placing eviden-tiary burdens on an applicant for a public benefit, when the benefit may be denied because of the nature of the applicant’s expressive and associational activities. Difficulties in proving the innocence of conduct may deter protected activity as much as a substantive standard that burdens privileged activity by its terms.
See N. Y. Judiciary Law § 466 and N. Y. Const., Art. 13, § 1, prescribing the following oath:
“I do solemnly swear (or affirm) that I will support the constitution of the United States, and the constitution of the State of New York, and that I will faithfully discharge the duties of the office of -, according to the best of my ability.”
Judge Motley’s separate opinion below states portions of appel-lees’ original, unrevised questionnaires that give some idea of appellees’ original conception of their mission under Rule 9406. These questionnaires, utilized in the First or the Second Judicial *191Department, or both, asked inter alia for a list of all “unfavorable incidents in your life,” a list containing “each and every club, association, society or organization of which you are or have been a member,” a list of “any articles for publication” written by an applicant. An applicant was asked whether he had ever “contributed in any way or signed a petition for” any subversive organization, or had “participated in any way whatsoever” in such organization’s activities. Each applicant was required to “[s]tate ... in not less than 100 words” what he thought were the “principles underlying the form of government of the United States.” See 299 F. Supp., at 137-139.
The revised questionnaires for the two departments, the ones passed upon by the court below, had eliminated the most obvious constitutional defects of the original questionnaires. Still, certain remaining questions were found wanting in the District Court’s opinion — for example, the precursor to present Question 26. In fact, the only question in the present questionnaire that appears to reflect an “extremely narrow” focus on insincerity of a prospective oath taker — Question 27 (a) — was drafted by the District Court as part of its final order. Appellees’ own proposed rewording was rejected.
See U. S. Const., Art. VI, cl. 3; U. S. Sup. Ct. Rule 5 (4).
In the Motion to Affirm appellees rely on the following language in Bond: “Nor is this a case where a legislator swears to an oath pro forma while declaring or manifesting his disagreement with or indifference to the oath.” 385 U. S., at 132. This negative characterization of the facts in Bond, barely a dictum, should not be read to approve systematic inquiry into beliefs and affiliations in order to test “sincerity.” Whatever a State may do when an oath taker himself contemporaneously “declares” or “manifests” contempt for the oath he is taking, it is quite a different matter to put the onus on a prospective oath taker to satisfy screening officials that his political activities and beliefs comport with the officials’ notions of “sincerity.” Indeed, Question 27 (a), which was written by the District Court, addresses the limited concerns of the Bond dictum and handles the remote risk that the oath-taking ceremony might be disrupted by an unwilling applicant. In pressing their search for sincerity beyond Question 27 (a), appellees cast serious doubt on their own assertion that Rule 9406 places no evidentiary burden on an applicant, and thereby reinforce the claim that Rule 9406 violates the principle of Speiser v. Randall, 357 U. S. 513 (1958). See n. 5 supra.
Part (a) of Question 26 is not rendered harmless by reason of the fact that part (b) limits somewhat the breadth of the question as a whole. In the first place, it must be remembered that neither part (a) nor part (b) states the operative criterion for excluding applicants on the basis of political affiliations — the criterion for exclusion, one of impermissible latitude, is given in Rule 9406 itself. Second, if all applicants who answer part (b) in the affirmative were therefore excluded, while those falling within part (a) only were admitted, the result would still be constitutionally problematical. See n. 11 infra. Third, overreaching inquiries are not cured simply by adding narrower follow-up questions. Obviously a State cannot hope to justify the sort of informational demand condemned today in In re Stolar, ante, p. 23, on the theory that the overintrusive inquiry is part of a series that culminates in a sufficiently narrow question. When the questioning is directed at the political activities and affiliations of applicants for a public benefit, the scope of questioning must be carefully limited in light of the permissible criteria for denying the benefit. Schneider v. Smith, 390 U. S. 17, 24 (1968); Shelton v. Tucker, 364 U. S. 479, 488 (1960). There is no justification for a requirement of overbroad disclosure that chills the exercise of First Amendment freedoms and is not tailored to serve valid governmental interests. See Gibson v. Florida Legislative Investigation Committee, 372 U. S. 539, 546 (1963); Bates v. Little Rock, 361 U. S. 516, 524 (1960); NAACP v. Alabama, 357 U. S. 449, 462-463 (1958).
Part (b) of Question 26 limits part (a) in one respect: applicants affiliated with an association of the kind characterized in part (a), but who do not endorse the association’s teachings concerning unlawful political change, need not answer part (b) in the affirmative. Naturally in other respects part (b) has the same sweep as part (a). “Specific intent” in this context means doctrinal agreement with the ideological tenets of part (a) associations — or, as appellees put it in their brief, “ 'specific intent’ to further the advocacy” of drastic change to be brought about in part by unlawful means. Again the “unlawful means” might be nonviolent or bloodthirsty. The association might be a discussion group lasting for a week. The advocacy might be oriented to a far and contingent future or to the here and now; it might be innocuous or likely to cause imminent and serious harm. A prospective applicant might well be in doubt whether particular associational activity evinces “specific intent” or not — or whether, years later perhaps, screening officials would be willing to infer this state of mind.