opinion: Mr. Justice Stewart
  delivered the opinion of the Court.
  On Wednesday, April 10, 1963, officials of Birmingham, Alabama, filed a bill of complaint in a state circuit court asking for injunctive relief against 139 individuals and two organizations. The bill and accompanying affidavits stated that during the preceding seven days:
  “[Respondents [had] sponsored and/or participated in and/or conspired to commit and/or to encourage and/or to participate in certain movements, plans or projects commonly called ‘sit-in’ demonstrations, ‘kneel-in’ demonstrations, mass street parades, trespasses on private property after being warned to leave the premises by the owners of said property, congregating in mobs upon the public streets and other public places, unlawfully picketing private places of business in the City of Birmingham, Alabama; violation of numerous ordinances and statutes of the City of Birmingham and State of Alabama . . . .”
  It was alleged that this conduct was “calculated to provoke breaches of the peace,” “threaten [ed] the safety, peace and tranquility of the City,” and placed “an undue burden and strain upon the manpower of the Police Department.”
  The bill stated that these infractions of the law were expected to continue and would “lead to further imminent danger to the lives, safety, peace, tranquility and general welfare of the people of the City of Birmingham,” and that the “remedy by law [was] inadequate.” The circuit judge granted a temporary injunction as prayed in the bill, enjoining the petitioners from, among other things, participating in or encouraging mass street parades or mass- processions without a permit as required by a Birmingham ordinance.
  Five of the eight petitioners were served with copies of the writ early the next morning. Several hours later four of them held a press conference. There a statement was distributed, declaring their intention to disobey the injunction because it was “raw tyranny under the guise of maintaining law and order.” At this press conference one of the petitioners stated: “That they had respect for the Federal Courts, or Federal Injunctions, but in the past the State Courts had favored local law enforcement, and if the police couldn’t handle it, the mob would.”
  That night a meeting took place at which one of the petitioners announced that “[ijnjunction or no injunction we are going to march tomorrow.” The next afternoon, Good Friday, a large crowd gathered in the vicinity of Sixteenth Street and Sixth Avenue North in Birmingham. A group of about 50 or 60 proceeded to parade along the sidewalk while a crowd of 1,000 to 1,500 onlookers stood by, “clapping, and hollering, and [w]hooping.” Some of the crowd followed the marchers and spilled out into the street. At least three of the petitioners participated in this march.
  Meetings sponsored by some of the petitioners were held that night and the following night, where calls for volunteers to “walk” and go to jail were made. On Easter Sunday, April 14, a crowd of between 1,500 and 2,000 people congregated in the midafternoon in the vicinity of Seventh Avenue and Eleventh Street North in Birmingham. One of the petitioners was seen organizing members of the crowd in formation. A group of about 50, headed by three other petitioners, started down the sidewalk two abreast. At least one other petitioner was among the marchers. Some 300 or 400 people from among the onlookers followed in a crowd that occupied the entire width of the street and overflowed onto the sidewalks. Violence occurred. Members of the crowd threw rocks that injured a newspaperman and damaged a police motorcycle.
  The next day the city officials who had requested the injunction applied to the state circuit court for an order to show cause why the petitioners should not be held in contempt for violating it. At the ensuing hearing the petitioners sought to attack the constitutionality of the injunction on the ground that it was vague and over-broad, and restrained free speech. They also sought to attack the Birmingham parade ordinance upon similar grounds, and upon the further ground that the ordinance had previously been administered in an arbitrary and discriminatory manner.
  The circuit judge refused to consider any of these contentions, pointing out that there had been neither a motion to dissolve the injunction, nor an effort to comply with it by applying for a permit from the city commission before engaging in the Good Friday and Easter Sunday parades. Consequently, the court held that the only issues before it were whether it had jurisdiction to issue the temporary injunction, and whether thereafter the petitioners had knowingly violated it. Upon these issues the court found against the petitioners, and imposed upon each of them a sentence of five days in jail and a $50 fine, in accord with an Alabama statute.
  The Supreme Court of Alabama affirmed. That court, too, declined to consider the petitioners’ constitutional attacks upon the injunction and the underlying Birmingham parade ordinance:
  “It is to be remembered that petitioners are charged with violating a temporary injunction. We are not reviewing a denial of a motion to dissolve or discharge a temporary injunction. Petitioners did not file any motion to vacate the temporary injunction until after the Friday and Sunday parades. Instead, petitioners deliberately defied the order of the court and did engage in and incite others to engage in mass street parades without a permit.
  “We hold that the circuit court had the duty and authority, in the first instance, to determine the validity of the ordinance, and, until the decision of the circuit court is reversed for error by orderly review, either by the circuit court or a higher court, the orders of the circuit court based on its decision are to be respected and disobedience of them is contempt of its lawful authority, to be punished. Howat v. State of Kansas, 258 U. S. 181.” 279 Ala. 53, 60, 62-63, 181 So. 2d 493, 500, 502.
  Howat v. Kansas, 258 U. S. 181, was decided by this Court almost 50 years ago. That was a case in which people had been punished by a Kansas trial court for refusing to obey an antistrike injunction issued under the state industrial relations act. They had claimed a right to disobey the court’s order upon the ground that the state statute and the injunction based upon it were invalid under the Federal Constitution. The Supreme Court of Kansas had affirmed the judgment, holding that the trial court “had general power to issue injunctions in equity and that, even if its exercise of the power was erroneous, the injunction was not void, and the defendants were pre-eluded from attacking it in this collateral proceeding . . . that, if the injunction was erroneous, jurisdiction was not thereby forfeited, that the error was subject to correction only by the ordinary method of appeal, and disobedience to the order constituted contempt.” 258 U. S., at 189.
  This Court, in dismissing the writ of error, not only unanimously accepted but fully approved the validity of the rule of state law upon which the judgment of the Kansas court was grounded:
  “An injunction duly issuing out of a court of general jurisdiction with equity powers upon pleadings properly invoking its action, and served upon persons made parties therein and within the jurisdiction, must be obeyed by them however erroneous the action of the court may be, even if the error be in the assumption of the validity of a seeming but void law going to the merits of the case. It is for the court of first instance to determine the question of the validity of the law, and until its decision is reversed for error by orderly review, either by itself or by a higher court, its orders based on its decision are to be respected, and disobedience of them is contempt of its lawful authority, to be punished.” 258 U. S., at 189-190.
  The rule of state law accepted and approved in Howat v. Kansas is consistent with the rule of law followed by the federal courts.
  In the present case, however, we are asked to hold that this rule of law, upon which the Alabama courts relied, was constitutionally impermissible. We are asked to say that the Constitution compelled Alabama to allow the petitioners to violate this injunction, to organize and engage in these mass street parades and demonstrations, without any previous effort on their part to have the injunction dissolved or modified, or any attempt to secure a parade permit in accordance with its terms. Whatever the limits of Howat v. Kansas, we cannot accept the petitioners’ contentions in the circumstances of this case.
  Without question the state court that issued the injunction had, as a court of equity, jurisdiction over the petitioners and over the subject matter of the controversy. And this is not a case where the injunction was transparently invalid or had only a frivolous pretense to validity. We have consistently recognized the strong interest of state and local governments in regulating the use of their streets and other public places. Cox v. New Hampshire, 312 U. S. 569; Kovacs v. Cooper, 336 U. S. 77; Poulos v. New Hampshire, 345 U. S. 395; Adderley v. Florida, 385 U. S. 39. When protest takes the form of mass demonstrations, parades, or picketing on public streets and sidewalks, the free passage of traffic and the prevention of public disorder and violence become important objects of legitimate state concern. As the Court stated, in Cox v. Louisiana, “We emphatically reject the notion . . . that the First and Fourteenth Amendments afford the same kind of freedom to those who would communicate ideas by conduct such as patrolling, marching, and picketing on streets and highways, as these amendments afford to those who communicate ideas by pure speech.” 379 U. S. 536, 555. And as a unanimous Court stated in Cox v. New Hampshire:
  “Civil liberties, as guaranteed by the Constitution, imply the existence of an organized society maintaining public order without which liberty itself would be lost in the excesses of unrestrained abuses. The authority of a municipality to impose regulations in order to assure the safety and convenience of the people in the use of public highways has never been regarded as inconsistent with civil liberties but rather as one of the means of safeguarding the good order upon which they ultimately depend.” 312 U. S., at 574.
  The generality of the language contained in the Birmingham parade ordinance upon which the injunction was based would unquestionably raise substantial constitutional issues concerning some of its provisions. Schneider v. State, 308 U. S. 147; Saia v. New York, 334 U. S. 558; Kunz v. New York, 340 U. S. 290. The petitioners, however, did not even attempt to apply to the Alabama courts for an authoritative construction of the ordinance. Had they done so, those courts might have given the licensing authority granted in the ordinance a narrow and precise scope, as did the New Hampshire courts in Cox v. New Hampshire and Poulos v. New Hampshire, both supra. Cf. Shuttlesworth v. Birmingham, 382 U. S. 87, 91; City of Darlington v. Stanley, 239 S. C. 139, 122 S. E. 2d 207. Here, just as in Cox and Poulos, it could not be assumed that this ordinance was void on its face.
  The breadth and vagueness of the injunction itself would also unquestionably be subject to substantial constitutional question. But the way to raise that question was to apply to the Alabama courts to have the injunction modified or dissolved. The injunction in all events clearly prohibited mass parading without a permit, and the evidence shows that the petitioners fully understood that prohibition when they violated it.
  The petitioners also claim that they were free to disobey the injunction because the parade ordinance on which it was based had been administered in the past in an arbitrary and discriminatory fashion. In support of this claim they sought to introduce evidence that, a few days before the injunction issued, requests for permits to picket had been made to a member of the city commission. One request had been rudely rebuffed, and this same official had later made clear that he was without power to grant the permit alone, since the issuance of such permits was the responsibility of the entire city commission. Assuming the truth of this proffered evidence, it does not follow that the parade ordinance was void on its face. The petitioners, moreover, did not apply for a permit either to the commission itself or to any commissioner after the injunction issued. Had they done so, and had the permit been refused, it is clear that their claim of arbitrary or discriminatory administration of the ordinance would have been considered by the state circuit court upon a motion to dissolve the injunction.
  This case would arise in quite a different constitutional posture if the petitioners, before disobeying the injunction, had challenged it in the Alabama courts, and had been met with delay or frustration of their constitutional claims. But there is no showing that such would have been the fate of a timely motion to modify or dissolve the injunction. There was an interim of two days between the issuance of the injunction and the Good Friday march. The petitioners give absolutely no explanation of why they did not make some application to the state court during that period. The injunction had issued ex parte; if the court had been presented with the petitioners’ contentions, it might well have disolved or at least modified its order in some respects. If it had not done so, Alabama procedure would have provided for an expedited process of appellate review. It cannot be presumed that the Alabama courts would have ignored the petitioners’ constitutional claims. Indeed, these contentions were accepted in another case by an Alabama appellate court that struck down on direct review the conviction under this very ordinance of one of thesé same petitioners.
  The rule of law upon which the Alabama courts relied in this case was one firmly established by previous precedents. We do not deal here, therefore, with a situation where a state court has followed a regular past practice of entertaining claims in a given procedural mode, and without notice has abandoned that practice to the detriment of a litigant who finds his claim foreclosed by a novel procedural bar. Barr v. City of Columbia, 378 U. S. 146. This is not a case where a procedural requirement has been sprung upon an unwary litigant when prior practice did not give him fair notice of its existence. Wright v. Georgia, 373 U. S. 284, 291.
  The Alabama Supreme Court has apparently never in any criminal contempt case entertained a claim of non-jurisdictional error. In Fields v. City of Fairfield, 273 Ala. 688, 143 So. 2d 177, decided just three years before the present case, the defendants, members of a “White Supremacy” organization who had disobeyed an injunction, sought to challenge the constitutional validity of a permit ordinance upon which the injunction was based. The Supreme Court of Alabama, finding that the trial court had jurisdiction, applied the same rule of law which was followed here:
  “As a general rule, an unconstitutional statute is an absolute nullity and may not form the basis of any legal right or legal proceedings, yet until its unconstitutionality has been judicially declared in appropriate proceedings, no person charged with its observance under an order or decree may disregard or violate the order or the decree with immunity from a charge of contempt of court; and he may not raise the question of its unconstitutionality in collateral proceedings on appeal from a judgment of conviction for contempt of the order or decree . . . .” 273 Ala., at 590, 143 So. 2d, at 180.
  These precedents clearly put the petitioners on notice that they could not bypass orderly judicial review of the injunction before disobeying it. Any claim that they were entrapped or misled is wholly unfounded, a conclusion confirmed by evidence in the record showing that when the petitioners deliberately violated the injunction they expected to go to jail.
  The rule of law that Alabama followed in this case reflects a belief that in the fair administration of justice no man can be judge in his own case, however exalted his station, however righteous his motives, and irrespective of his race, color, politics, or religion. This Court cannot hold that the petitioners were constitutionally free to ignore all the procedures of the law and carry their battle to the streets. One may sympathize with the petitioners’ impatient commitment to their cause. But respect for judicial process is a small price to pay for the civilizing hand of law, which alone can give abiding meaning to constitutional freedom.
  Affirmed.
  APPENDIX A TO OPINION OF THE COURT.
  “Temporary Injunction — April 10, 1963.
  “A verified Bill of Complaint in the above styled cause having been presented to me on this the 10th of April 1963 at 9:00 O’Clock P. M. in the City of Birmingham, Alabama.
  “Upon consideration of said verified Bill of Complaint and the affidavits of Captain G. Y. Evans and Captain George Wall, and the public welfare, peace and safety requiring it, it is hereby considered, ordered, adjudged and decreed that a peremptory or a temporary writ of injunction be and the same is hereby issued in accordance with the prayer of said petition.
  “It is therefore ordered, adjudged and decreed by the Court that upon the complainant entering into a good and sufficient bond conditioned as provided by law, in the sum of Twenty five Hundred Dollars ($2500.00), same to be approved by the Register of this Court that the Register issue a peremptory or temporary writ of injunction that the respondents and the others identified in said Bill of Complaint, their agents, members, employees, servants, followers, attorneys, successors and all other persons in active concert or participation with the respondents and all persons having notice of said order from continuing any act hereinabove designated particularly: engaging in, sponsoring, inciting or encouraging mass street parades or mass processions or like demonstrations without a permit, trespass on private property after being warned to leave the premises by the owner or person in possession of said private property, congregating on the street or public places into mobs, and unlawfully picketing business establishments or public buildings in the City of Birmingham, Jefferson County, State of Alabama or performing acts calculated to cause breaches of the peace in the City of Birmingham, Jefferson County, in the State of Alabama or from conspiring to engage in unlawful street parades, unlawful processions, unlawful demonstrations, unlawful boycotts, unlawful trespasses, and unlawful picketing or other like unlawful conduct or from violating the ordinances of the City of Birmingham and the Statutes of the State of Alabama or from doing any acts designed to consummate conspiracies to engage in said unlawful acts of parading, demonstrating, boycotting, trespassing and picketing or other unlawful acts, or from engaging in acts and conduct customarily known as 'kneel-ins’ in churches in violation of the wishes and desires of said churches.
  “W. A. Jenkins, Jr., As Circuit Judge of the Tenth Judicial Circuit of Alabama, In Equity Sitting.”
  APPENDIX B TO OPINION OF THE COURT.
  “In our struggle for freedom we have anchored our faith and hope in the rightness of the Constitution and the moral laws of the universe.
  “Again and again the Federal judiciary has made it clear that the priviledges [sic] guaranteed under the First and the Fourteenth Amendments are to [sic] sacred to be trampled upon by the machinery of state government and police power. In the past we have abided by Federal injunctions out of respect for the forthright and consistent leadership that the Federal judiciary has given in establishing the principle of integration as the law of the land.
  “However we are now confronted with recalcitrant forces in the Deep South that will use the courts to perpetuate the unjust and illegal system of racial separation.
  “Alabama has made clear its determination to defy the law of the land. Most of its public officials, its legislative body and many of its law enforcement agents have openly defied the desegregation decision of the Supreme Court. We would feel morally and legal [sic] responsible to obey the injunction if the courts of Alabama applied equal justice to all of its citizens. This would be sameness made legal. However the ussuance [sic] of this injunction is a blatant of difference made legal.
  “Southern law enforcement agencies have demonstrated now and again that they will utilize the force of law to misuse the judicial process.
  “This is raw tyranny under the guise of maintaining law and order. We cannot in all good conscience obey such an injunction which is an unjust, undemocratic and unconstitutional misuse of the legal process.
  “We do this not out of any desrespect [sic] for the law but out of the highest respect for the law. This is not an attempt to evade or defy the law or engage in chaotic anarchy. Just as in all good conscience we cannot obey unjust laws, neither can we respect the unjust use of the courts.
  “We believe in a system of law based on justice and morality. Out of our great love for the Constitution of the U. S. and our desire to purify the judicial system of the state of Alabama, we risk this critical move with an awareness of the possible consequences involved.”
  The text of the injunction is reproduced as Appendix A to this opinion.
  The Birmingham parade ordinance, § 1159 of the Birmingham City Code, provides that:
  “It shall be unlawful to organize or hold, or to assist in organizing or holding, or to take part or participate in, any parade or procession or other public demonstration on the streets or other public ways of the city, unless a permit therefor has been secured from the commission.
  “To secure such permit, written application shall be made to the commission, setting forth the probable number of persons, vehicles and animals which will be engaged in such parade, procession or other public demonstration, the purpose for which it is to be held or had, and the streets or other public ways over, along or in which it is desired to have or hold such parade, procession or other public demonstration. The commission shall grant a written permit for such parade, procession or other public demonstration, prescribing the streets or other public ways which may be used therefor, unless in its judgment the public welfare, peace, safety, health, decency, good order, morals or convenience require that it be refused. It shall be unlawful to use for such purposes any other streets or public ways than those set out in said permit.
  “The two preceding paragraphs, however, shall not apply to funeral processions.”
  The full statement is reproduced as Appendix B to this opinion.
  “The circuit court, or judges thereof when exercising equity jurisdiction and powers may punish for contempt by fine not exceeding fifty dollars, and by imprisonment, not exceeding five days, one or both.” Ala. Code, Tit. 13, § 143. See also id., §§ 4-5, 126.
  The circuit court dismissed the contempt proceedings against several individuals on grounds of insufficient evidence.
  Those petitioners who participated in the April 11 press conference contend that the circuit court improperly relied on this incident in finding them guilty of contempt, claiming that they were engaged in constitutionally protected free speech. We find no indication that the court considered the incident for any purpose other than the legitimate one of establishing that the participating petitioners’ subsequent violation of the injunction by parading without a permit was willful and deliberate.
  The Alabama Supreme Court quashed the conviction of one defendant because of insufficient proof that he knew of the injunction before violating it, and the convictions of two others because there was no showing that they had disobeyed the order. 279 Ala. 53, 64, 181 So. 2d 493, 504.
  Two of the petitioners here claim that there was a complete dearth of evidence to establish that they had knowledge of the injunction before violating it, and that their convictions are therefore constitutionally defective under the principle of Thompson v. Louisville, 362 U. S. 199. The Alabama Supreme Court’s recitation of the evidence on this issue, which is supported by the record, plainly shows this claim is without foundation. It is, of course, a familiar doctrine that proof of the elements of criminal contempt may be established by circumstantial evidence. Bullock v. United States, 265 F. 2d 683, cert. denied sub nom. Kasper v. United States, 360 U. S. 932.
  Brougham v. Oceanic Steam Navigation Co., 205 F. 857; Trickett v. Kaw Valley Drainage Dist., 25 F. 2d 851, cert. denied, 278 U. S. 624; O’Hearne v. United States, 62 App. D. C. 285, 66 F. 2d 933, cert. denied, 290 U. S. 683; Locke v. United States,, 75 F. 2d 157, cert. denied, 295 U. S. 733; McCann v. New York Stock Exchange, 80 F. 2d 211, cert. denied sub nom. McCann v. Leibell, 299 U. S. 603; McLeod v. Majors, 102 F. 2d 128; Kasper v. Brittain, 245 F. 2d 92, cert. denied, 355 U. S. 834. See also Ex parte Rowland, 104 U. S. 604; In re Ayers, 123 U. S. 443; In re Burras, 136 U. S. 586; United States v. Shipp, 203 U. S. 563; United States v. Mine Workers, 330 U. S. 258.
  In In re Green, 369 U. S. 689, the petitioner was convicted of criminal contempt for violating a labor injunction issued by an Ohio court. Relying on the pre-emptive command of the federal labor law, the Court held that the state courts were required to hear Green’s claim that the state court was without jurisdiction to issue the injunction. The petitioner in Green, unlike the petitioners here, had attempted to challenge the validity of the injunction before violating it by promptly applying to the issuing court for an order vacating the injunction. The petitioner in Green had further ofered to prove that the court issuing the injunction had agreed to its violation as an appropriate means of testing its validity.
  Ala. Const., Art. 6, § 144; Ala. Code, Tit. 7, §§ 1038-1039.
  See n. 1, supra.
  Mrs. Lola Hendricks, not a petitioner in this ease, testified that on April 3:
  “I went to Mr. Connor’s office, the Commissioner’s office at the City Hall Building. We went up and Commissioner Connor met us at the door. He asked, ‘May I help you?’ I told him, ‘Yes, sir, we came up to apply or see about getting a permit for picketing, parading, demonstrating.’
  “I asked Commissioner Connor for the permit, and asked if he could issue the permit, or other persons who would refer me to, persons who would issue a permit. He said, ‘No, you will not get a permit in Birmingham, Alabama to picket. I will picket you over to the City Jail,’ and he repeated that twice.”
  Commissioner Connor sent the following telegram to one of the petitioners on April 5:
  “Under the provisions of the city code of the City of Birmingham, a permit to picket as requested by you cannot be granted by me individually but is the responsiboity [sic] of the entire commission. I insist that you and your people do not start any picketing on the streets in Birmingham, Alabama.
  “Eugene ‘Bull’ Connor, Commissioner of Public Safety.”
  In its opinion, that court stated: “The legal and orderly processes of the Court would require the defendants to attack the unreasonable denial of such permit by the Commission of the City of Birmingham through means of a motion to dissolve the injunction at which time this Court would have the opportunity to pass upon the question of whether or not a compliance with the ordinance was attempted and whether or not an arbitrary and capricious denial of such request was made by the Commission of the City of Birmingham. Since this course of conduct was not sought by the defendants, the Court is of the opinion that the validity of its injunction order stands upon its prima facie authority to execute the same.”
  Ala. Code, Tit. 7 App., Sup. Ct. Rule 47.
  Shuttlesworth v. City of Birmingham, 43 Ala. App. 68, 180 So. 2d 114. The ease is presently pending on certiorari review in the Alabama Supreme Court.
  As early as 1904, the Alabama Supreme Court noted that: “An evident distinction is to be made in contempt proceedings for the violation of the writ of injunction, where the writ is improvidently or irregularly issued, and where it is issued without jurisdiction ...” Old Dominion Telegraph Co. v. Powers, 140 Ala. 220, 226, 37 So. 195, 197. See Board of Revenue of Covington County v. Merrill, 193 Ala. 521, 68 So. 971.
  Reversed on other grounds, 375 U. S. 248.
  The same rule of law was followed in Kasper v. Brittain, 245 F. 2d 92. There, a federal court had ordered the public high school in Clinton, Tennessee, to desegregate. Kasper “arrived from somewhere in the East,” and organized a campaign “to run the Negroes out of the school.” The federal court issued an ex parte restraining order enjoining Kasper from interfering with desegregation. Relying upon the First Amendment, Kasper harangued a crowd “to the effect that although he had been served with the restraining order, it did not mean anything . . . .” His conviction for criminal contempt was affirmed by the Court of Appeals for the Sixth Circuit. That court concluded that “an injunetional order issued by a court must be obeyed,” whatever its seeming invalidity, citing Howat v. Kansas, 258 U. S. 181. This Court denied certiorari, 355 U. S. 834.
choices: First Amendment, miscellaneous (cf. comity: First Amendment) commercial speech, excluding attorneys libel, defamation: defamation of public officials and public and private persons libel, privacy: true and false light invasions of privacy legislative investigations: concerning internal security only federal or state internal security legislation: Smith, Internal Security, and related federal statutes loyalty oath or non-Communist affidavit (other than bar applicants, government employees, political party, or teacher) loyalty oath: bar applicants (cf. admission to bar, state or federal or U.S. Supreme Court) loyalty oath: government employees loyalty oath: political party loyalty oath: teachers security risks: denial of benefits or dismissal of employees for reasons other than failure to meet loyalty oath requirements conscientious objectors (cf. military draftee or military active duty) to military service campaign spending (cf. governmental corruption): protest demonstrations (other than as pertains to sit-in demonstrations): demonstrations and other forms of protest based on First Amendment guarantees free exercise of religion establishment of religion (other than as pertains to parochiaid:) parochiaid: government aid to religious schools, or religious requirements in public schools obscenity, state (cf. comity: privacy): including the regulation of sexually explicit material under the 21st Amendment obscenity, federal