delivered the opinion of the Court.
Appellants brought a declaratory judgment action in the Supreme Court of New York, Kings County, praying that § 12-a of the Civil Service Law,1 as implemented by *487the so-called Feinberg Law,2 be declared unconstitutional, and that action by the Board of Education of the City of New York thereunder be enjoined. On motion for judgment on the pleadings, the court held that subdivision (c) of § 12-a, the Feinberg Law, and the Rules of the State Board of Regents promulgated thereunder violated the Due Process Clause'of the Fourteenth Amendment, and issued an injunction. 196 Misc. 873, 95 N. Y. S. 2d 114. The Appellate Division of the Supreme Court reversed, 276 App. Div. 527, 96 N. Y. S. 2d 466, and the Court of Appeals affirmed the judgment of the Appellate Division, 301 N. Y. 476, 95 N. E. 2d 806. The appellants come here by appeal under 28 U. S. C. § 1257.
Section 12-a of the Civil Service Law, hereafter referred to as § 12-a, is set forth in the margin.3 To implement *488this law, the Feinberg Law was passed, adding a new section, § 3022, to the Education Law of the State of New York, which section so far as here pertinent is set forth in the margin.4 The Feinberg Law was also to implement *489§ 3021 of the Education Law of New York.5 The constitutionality of this section was not attacked in the proceedings below.
The preamble of the Feinberg Law, § 1, makes elaborate findings that members of subversive groups, particularly of the Communist Party and its affiliated organizations, have been infiltrating into public employment in the public schools of the State; that this has occurred and continues notwithstanding the existence of protective statutes designed to prevent the appointment to or retention in employment in public office, and particularly in the public schools, of members of any organizations which teach or advocate that the government of the United States or of any state or political subdivision thereof shall be overthrown by force or violence or by any other unlawful means. As a result, propaganda can be disseminated among the children by those who teach them and to whom they look for guidance, authority, and leadership. The Legislature further found that the members of such groups use their positions to advocate and teach their doctrines, and are frequently bound by *490oath, agreement, pledge, or understanding to follow, advocate and teach a prescribed party line or group dogma or doctrine without regard to truth or free inquiry. This propaganda, the Legislature declared, is sufficiently subtle to escape detection in the classroom; thus, the menace of such infiltration into the classroom is difficult to measure. Finally, to protect the children from such influence, it was thought essential that the laws prohibiting members of such groups, such as the Communist Party or its affiliated organizations-, from obtaining or retaining employment in the public schools be rigorously enforced. It is the purpose of the Feinberg Law to provide for the disqualification and removal of superintendents of schools, teachers, and employees in the public schools in any city or school district of the State who advocate the overthrow of the Government by unlawful means or who are members of organizations which have a like purpose.
Section 3022 of the Education Law, added by the Feinberg Law, provides that the Board of Regents, which has charge of the public school system in the State of New York, shall, after full notice and hearing, make a listing of organizations which it finds advocate, advise, teach, or embrace the doctrine that the government should be overthrown by force or violence or any other unlawful means, and that such listing may be amended and revised from time to’time.
It will be observed that the listings are made only after full- notice and hearing. In addition, the Court of Appeals construed the statute in conjunction with Article 78 of the New York Civil Practice Act, Gilbert-Bliss’ N. Y. Civ. Prac., Vol. 6B, so as to provide listed organizations a right of review.
The Board of Regents is further authorized to provide in rules and regulations, and has so provided, that membership in any listed organization, after notice and hearing, “shall constitute prima facie evidence for disquali*491fication for appointment to or retention in any office or position in the school system”; 6 but before one who is an employee or seeks employment is severed from or denied employment, he likewise must be given a full hearing with the privilege of being represented by counsel and the right to judicial review.7 It is § 12-a of the Civil Service Law, as implemented by the Feinberg Law as above indicated, that is under attack here.
It is first argued that the Feinberg Law and the rules promulgated thereunder constitute an abridgment of the *492freedom of speech and assembly of persons employed or seeking employment in the public schools of the State of New York.
It is clear that such persons have the right under our law to assemble, speak, think and believe as they will. Communications Assn. v. Douds, 339 U. S. 382. It is equally clear that they have no right to work for the State in the school system on their own terms. United Public Workers v. Mitchell, 330 U. S. 75. They may work for the school system upon the reasonable terms laid down by the proper authorities of New York. If they do not choose to work on such terms, they are at liberty to retain their beliefs and associations and go elsewhere. ■ Has the State thus deprived them of any right to free speech or assembly? We think not. Such persons are or may be denied, under the statutes in question, the privilege of working for the school system of the State of New York because, first, of their advocacy of the overthrow of the government by force or violence, or, secondly, by unexplained membership in an organization found by the school authorities, after notice and hearing, to teach and advocate the overthrow of the government by force or violence, and known by such persons to have such purpose.
The constitutionality of the first proposition is not questioned here. Gitlow v. New York, 268 U. S. 652, 667-672, construing § 161 of the New York Penal Law.
As to the second, it is rather subtly suggested that we should not follow our recent decision in Garner v. Los Angeles Board, 341 U. S. 716. We there said:
“We think that a municipal employer is not disabled because it is an agency of the State from inquiring of its employees as to matters that may prove relevant to their fitness and suitability for the public service. Past conduct may well relate to present fitness; past loyalty may have a reasonable relation*493ship to present and future trust. Both are commonly inquired into in determining fitness for both high and low positions in private industry and are not less relevant in public employment.” 341 U. S., at p. 720.
We adhere to that case. A teacher works in a sensitive area in a schoolroom. There he shapes the attitude of young minds towards the society in which they live. In this, the state has a vital concern. It must preserve the integrity of the schools. That the school authoritiés have the right and the duty to screen the officials, teachers, and employees as to their fitness to maintain the integrity of the schools as a part of ordered society, cannot be doubted. One’s associates, past and present, as well as one’s conduct, may properly be considered in determining fitness and loyalty. From time immemorial, one’s reputation has been determined in part by the company he keeps. In the employment of officials and teachers of the school system, the state may very properly inquire into the company they keep, and we know of no rule, constitutional or otherwise, that prevents the state, when determining the fitness and loyalty of such persons, from considering the organizations and persons with whom they associate.
If, under the procedure set up in the New York law, a person, is found to be unfit and is disqualified from employment in the public school system because of membership in a listed organization, he is not thereby denied the right of free speech and assembly. His freedom of choice between membership in the organization' and employment in the school system might be limited, but not his freedom of speech or assembly, except in the remote sense that limitation is inherent in every choice. Certainly such limitation is not one the state may not make in the exercise of its police power to protect the schools from pollution and thereby to defend its own existence.
*494It is next argued by appellants that the provision in § 3022 directing the Board of Regents to provide in rules and regulations that membership in any organization listed by the Board after notice and hearing, with provision for review in accordance with the' statute, shall constitute prima facie evidence of disqualification, denies due process, because the fact found bears no relation to the fact presumed. In other words, from the fact found that the organization was one that advocated the overthrow of government by unlawful means and that the pérson employed or to be employed was a member of the organization and knew of its purpose,8 to presume that such member is disqualified for employment is so unreasonable as to be a denial of due process of law. We do not agree.
“The law of evidence is full of presumptions either of fact or law. The former are, of course, disputable, and the strength of any inference of one fact from proof of another depends upon the generality of the experience upon which it is founded. . . .
“Legislation providing that proof of one fact shall constitute prima facie evidence of the main fact in issue is but to enact a rule of evidence, and quite within the general power of government. Statutes, National and state, dealing with such methods of proof in both civil and criminal cases abound, and the decisions upholding them are numerous.” Mobile, J. & K. C. R. Co. v. Turnipseed, 219 U. S. 35, at p. 42.
Membership in a listed organization found to be within the statute and known by the member to be within the *495statute is a legislative finding that the member by his membership supports the thing the organization stands for, namely, the overthrow of government by unlawful means. We cannot say that such a finding is contrary to fact or that "generality of experience” points to a different conclusion. Disqualification follows therefore as a reasonable presumption from such membership and support. Nor is there here a problem of procedural due process. The presumption is not conclusive but arises only in a hearing where the person against whom it may arise has full opportunity to rebut it. The holding of the Court of Appeals below is significant in this regard:
“The statute also makes it clear that . . . proof of such membership ‘shall constitute prima facie evidence of disqualification’ for such employment. But, as was said in Potts v. Pardee (220 N. Y. 431, 433): ‘The presumption growing out of a prima facie case . . . remains only so long as there is no substantial evidence to the contrary. When that is offered the presumption disappears, and unless met by further proof there is nothing to justify a finding based solely upon it.’ Thus the phrase ‘prima facie evidence of disqualification,’ as used in the statute, imports a hearing at which one who seeks appointment to or retention in a public school position shall be afforded, an opportunity to. present substantial evidence contrary to the presumption sanctioned by . the prima facie evidence for which subdivision 2 of section 3022 makes provision. Once such contrary evidence has been received, however, the official who made the order of ineligibility has thereafter the burden of sustaining the validity of that order by a fair preponderance of the evidence. (Civil Service Law, § 12-a, subd. [d].) Should an order of ineligibility then issue, the party aggrieved thereby may avail himself of the provisions for review prescribed by *496the section of the statute last cited above. In that view there here, arises no question of procedural due process.” 301 N. Y. 476, at p. 494, 95 N. E. 2d 806, at 814-815.
Where, as here, the relation between the fact found and the presumption is clear and direct and is not conclusive, the requirements of due process are satisfied.
Without raising in the complaint or in the proceedings in the lower courts the question of the constitutionality of § 3021 of the Education Law of New York, appellants urge here for the first time that this section is unconstitutionally vague. The question is not before us. We will not pass upon the constitutionality of a state statute before the state courts have had an opportunity to do so. Asbury Hospital v. Cass County, 326 U. S. 207, 213-216; Alabama State Federation of Labor v. McAdory, 325 U. S. 450, 460-462; Plymouth Coal Co. v. Pennsylvania, 232 U. S. 531, 546.
It is also suggested that the use of the word “subversive” is vague and indefinite. But the word is first used in § 1 of the Feinberg Law, which is the preamble to the Act, and not in a definitive part thereof. When used in subdivision 2 of § 3022, the word has a very definite meaning, namely, an organization that teaches and advocates the overthrow of government by force or violence.
We find no constitutional infirmity in § 12-a of the Civil Service Law of New York or in the Feinberg Law which implemented it, and the judgment is
Affirmed.
N. Y. Laws 1939, c. 547, as amended N. Y. Laws 1940, c. 564.
N. Y. Laws 1949, c. 360.
Ҥ 12-a. Ineligibility
“No person shall be appointed to any office or position in the service of the state or of any civil division or city thereof, nor shall any person presently employed in any such office dr position be continued in such employment, nor shall any person be employed in the public service as superintendents, principals or teachers in a public school or academy or in a state normal school or college, or any other state educational institution who: (a) By word of mouth or writing wilfully and deliberately advocates, advises or teaches the doctrine that the government of the United States or of any state or of any political subdivision thereof should be overthrown or overturned by force, violence or any unlawful means; or
“(b) Prints, publishes, edits, issues or sells, any book, paper, document or written or printed matter in any form containing or advocating, advising or teaching the doctrine that the ‘ government of the United States or of any state or of any political subdivision thereof should be overthrown by force, violence or any unlawful means, and who ■ advocates, advises, teaches, or embraces the duty, necessity or propriety of adopting the doctrine contained therein;
“(c) Organizes or helps to organize or becomes a member of any society or group of persons which teaches or advocates that the government of the United States or of any state or of any political sub*488division thereof shall be overthrown by force or violence, or by any unlawful means;
“(d) A person dismissed or declared ineligible may within four months of such dismissal or declaration of ineligibility be entitled to petition for an order to show cause signed by a justice of the supreme court, why a hearing on such charges should not be had. Until the final judgment on said hearing is entered, the order to show cause shall stay the effect of any order of dismissal or ineligibility based on the provisions of this section. The hearing shall consist of the taking of testimony in open court with opportunity for cross-examination. The burden of sustaining .the validity of the order of dismissal or ineligibility by a fair preponderance of the credible evidence shall be upon the person making such dismissal or order of ineligibility.”
Ҥ 3022. Elimination of subversive persons from the public school system
“1. The board of regents shall adopt, promulgate, and enforce rules and regulations for the disqualification or removal of superintendents of schools, teachers or employees in the public schools in any city or school district of the state who violate the provisions of section three thousand twenty-one of this article or who are ineligible for appointment to or retention in any office or position in such public schools on any of the grounds set forth in section twelve-a of the civil service law-and shall provide therein appropriate methods and procedure for the enforcement of such sections of this article and the civil service law.
“2. The board of regents shall, after inquiry, and after such notice and hearing as may be appropriate, make a listing of organizations which it finds to be subversive in that they advocate, advise, teach or embrace the doctrine that the government of the United States or of any state or of any political subdivision thereof shall be overthrown or overturned by force, violence or any unlawful means, or that they advocate, advise, teach or embrace the duty, necessity or propriety of adopting any such doctrine, as set forth in section twelve-a of the civil service law. Such listings may be amended and revised from time to time. The board, in making such inquiry, may utilize any similar listings or designations promulgated by any federal *489agency or authority authorized by federal law, regulation or executive order, and for the purposes of such inquiry, the board may request and receive from such federal agencies or authorities any supporting material or evidence that may be made available to it. . The board of regents shall provide in the rules and regulations required by subdivision one hereof that membership in any such organization included in such listing made by it shall constitute prima facie evidence of disqualification for appointment to or retention in any office or position in the public schools of the state.”
Ҥ 3021. ,Removal of superintendents, teachers and employees for treasonable or seditious acts or utterances
“A person employed as superintendent of schools, teacher or employee in the public schools, in any city or school district of the state, shall be removed from such position for the utterance of any treasonable or seditious word or words or the doing of any treasonable or seditious act or acts while holding such position.”
Ҥ 254. Disqualification or removal of superintendents, teachers and other employes.
“2. List of subversive organizations to be issued. Pursuant to chapter 360 of the Laws of 1949, the Board of Regents will issue a list, which may be amended and revised from time to time, of organizations which the Board finds to be subversive in that they advocate, advise, teach or embrace the doctrine that the Government of the United States, or of any state or of any political subdivision thereof, shall be overthrown or overturned by force, violence . or any unlawful means, or that they advocate, advise, teach or embrace the duty, necessity or propriety of adopting any such doctrine, as set forth in section 12-a of the Civil Service Law. Evidence of membership in any organization so listed on or after the tenth day subsequent to the date of official promulgation of such list shall constitute prima facie evidence of disqualification for appointment to or. retention of any office or position in the school system. Evidence of membership in such an organization prior to said day shall be presumptive evidence that membership has continued, in the absence of a showing that such membership has been terminated in good faith.” Official Compilation of Codes, Rules arid Regulations of the State of New York (Fifth Supp.), Vol. 1, pp. 205-206.
The Court of Appeals construed the statute in conjunction with § 12-a subd. [d], supra, n. 3. The Rules of the Board of Regents provided: “In all cases all rights to a fair trial, representation by counsel and appeal or court review as provided by statute or the Constitution shall be scrupulously observed.” Section 254, 1 (e), Official Compilation of Codes, Rules and Regulations of the State of New York (Fifth Supp.), Vol. 1, p. 206.
In the proceedings below, both the Appellate Division of the Supreme Court and the Court of Appeals construed the statute to require such knowledge. 276 App. Div. 527, 530, 96 N. Y. S. 2d 466, 470-471; 301 N. Y. 476, 494, 95 N. E. 2d 806, 814-815.