class thereof is in session, shall willfully make or assist in the making of any noise or diversion which disturbs or tends to disturb the peace or good order of such school session or class thereof. . . ." Code of Ordinances, c. 28, § 19.2 (a).

Appellant claims that, on its face, this ordinance is both vague and overbroad, and therefore unconstitutional. We conclude, however, that the ordinance suffers from neither of these related infirmities.

A. Vagueness

It is a basic principle of due process that an enactment is void for vagueness if its prohibitions are not clearly defined. Vague laws offend several important values. First, because we assume that man is free to steer between lawful and unlawful conduct, we insist that laws give the person of ordinary intelligence a reasonable opportunity to know what is prohibited, so that he may act accordingly. Vague laws may trap the innocent by not providing fair warning. Second, if arbitrary and discriminatory enforcement is to be prevented, laws must provide explicit standards for those who apply them. A vague law impermissibly delegates

3

3 E. g., Papachristou v. City of Jacksonville, 405 U. S. 156, 162 (1972); Cramp v. Board of Public Instruction, 368 U. S. 278, 287 (1961); United States v. Harriss, 347 U. S. 612, 617 (1954); Jordan v. De George, 341 U. S. 223, 230-232 (1951); Lanzetta v. New Jersey, 306 U. S. 451, 453 (1939); Connally v. General Construction Co., 269 U. S. 385, 391 (1926); United States v. Cohen Grocery Co., 255 U. S. 81, 89 (1921); International Harvester Co. v. Kentucky, 234 U. S. 216, 223-224 (1914).

4 E. g., Papachristou v. City of Jacksonville, supra; Coates v. Cincinnati, 402 U. S. 611, 614 (1971); Gregory v. Chicago, 394 U. S. 111, 120 (1969) (Black, J., concurring); Interstate Circuit v. Dallas, 390 U. S. 676, 684-685 (1968); Ashton v. Kentucky, 384 U. S. 195, 200 (1966); Giaccio v. Pennsylvania, 382 U. S. 399 (1966); Shuttlesworth v. Birmingham, 382 U. S. 87, 90-91 (1965); Kunz v. New

At the time of appellant's arrest and conviction, Rockford's antipicketing ordinance provided that

"A person commits disorderly conduct when he knowingly:

"(i) Pickets or demonstrates on a public way within 150 feet of any primary or secondary school building while the school is in session and one-half hour before the school is in session and one-half hour after the school session has been concluded, provided that this subsection does not prohibit the peaceful picketing of any school involved in a labor dispute . Code of Ordinances, c. 28, § 18.1 (i).

This ordinance is identical to the Chicago disorderly conduct ordinance we have today considered in Police Department of Chicago v. Mosley, ante, p. 92. For the reasons given in Mosley, we agree with dissenting Justice Schaefer below, and hold that § 18.1 (i) violates the Equal Protection Clause of the Fourteenth Amendment. Appellant's conviction under this invalid ordinance must be reversed.2

II

The antinoise ordinance reads, in pertinent part, as follows:

"[N]o person, while on public or private grounds adjacent to any building in which a school or any

2 In November 1971, the antipicketing ordinance was amended to delete the labor picketing proviso. As Rockford notes, "This amendment and deletion has, of course, no effect on Appellant's personal situation." Brief 2. Necessarily, we must consider the facial constitutionality of the ordinance in effect when appellant was arrested and convicted.

a point"; that the only noise was made by policemen using loudspeakers; that almost no students were noticeable at the schoolhouse windows; and that orderly school procedure was not disrupted.

After warning the demonstrators, the police arrested 40 of them, including appellant.1 For participating in the demonstration, Grayned was tried and convicted of violating two Rockford ordinances, hereinafter referred to as the "antipicketing" ordinance and the "antinoise" ordinance. A $25 fine was imposed for each violation. Since Grayned challenged the constitutionality of each ordinance, he appealed directly to the Supreme Court of Illinois. Ill. Sup. Ct. Rule 302. He claimed that the ordinances were invalid on their face, but did not urge that, as applied to him, the ordinances had punished constitutionally protected activity. The Supreme Court of Illinois held that both ordinances were constitutional on their face. 46 Ill. 2d 492, 263 N. E. 2d 866 (1970). We noted probable jurisdiction, 404 U. S. 820 (1971). We conclude that the antipicketing ordinance is unconstitutional, but affirm the court below with respect to the antinoise ordinance.

1 Police officers testified that "there was no way of picking out any one in particular" while making arrests. Report of Proceedings in Circuit Court, 17th Judicial Circuit, Winnebago County 66. However, apparently only males were arrested. Id., at 65, 135, 147. Since appellant's sole claim in this appeal is that he was convicted under facially unconstitutional ordinances, there is no occasion for us to evaluate either the propriety of these selective arrests or the sufficiency of evidence that appellant himself actually engaged in conduct within the terms of the ordinances. MR. JUSTICE DOUGLAS, in concluding that appellant's particular behavior was protected by the First Amendment, reaches a question not presented by the parties here or in the court below. See Tr. of Oral Arg. 16-17; Jurisdictional Statement 3; City of Rockford v. Grayned, 46 Ill. 2d 492, 494, 263 N. E. 2d 866, 867 (1970).

MR. JUSTICE MARSHALL delivered the opinion of the Court.

Appellant Richard Grayned was convicted for his part in a demonstration in front of West Senior High School in Rockford, Illinois. Negro students at the school had first presented their grievances to school administrators. When the principal took no action on crucial complaints, a more public demonstration of protest was planned. On April 25, 1969, approximately 200 people—students, their family members, and friends gathered next to the school grounds. Appellant, whose brother and twin sisters were attending the school, was part of this group. The demonstrators marched around on a sidewalk about 100 feet from the school building, which was set back from the street. Many carried signs which summarized the grievances: "Black cheerleaders to cheer too"; "Black history with black teachers"; "Equal rights, Negro counselors." Others, without placards, made the "power to the people" sign with their upraised and clenched fists.

In other respects, the evidence at appellant's trial was sharply contradictory. Government witnesses reported that the demonstrators repeatedly cheered, chanted, baited policemen, and made other noise that was audible in the school; that hundreds of students were distracted from their school activities and lined the classroom windows to watch the demonstration; that some demonstrators successfully yelled to their friends to leave the school building and join the demonstration; that uncontrolled latenesses after period changes in the school were far greater than usual, with late students admitting that they had been watching the demonstration; and that, in general, orderly school procedure was disrupted. Defense witnesses claimed that the demonstrators were at all times quiet and orderly; that they did not seek to violate the law, but only to "make

Syllabus

408 U.S.

GRAYNED v. CITY OF ROCKFORD

APPEAL FROM THE SUPREME COURT OF ILLINOIS

No. 70-5106. Argued January 19, 1972-Decided June 26, 1972

1. Antipicketing ordinance, virtually identical with one invalidated as violative of equal protection in Police Department of Chicago v. Mosley, ante, p. 92, is likewise invalid. P. 107.

2. Antinoise ordinance prohibiting a person while on grounds adjacent to a building in which a school is in session from willfully making a noise or diversion that disturbs or tends to disturb the peace or good order of the school session is not unconstitutionally vague or overbroad, The ordinance is not vague since, with fair warning, it prohibits only actual or imminent, and willful, interference with normal school activity, and is not a broad invitation to discriminatory enforcement. Cox v. Louisiana, 379 U. S. 536; Coates v. Cincinnati, 402 U. S. 611, distinguished. The ordinance is not overbroad as unduly interfering with First Amendment rights since expressive activity is prohibited only if it "materially disrupts classwork." Tinker v. Des Moines School District, 393 U. S. 503, 513. Pp. 107-121.

46 Ill. 2d 492, 263 N. E. 2d 866, affirmed in part and reversed in part.

MARSHALL, J., delivered the opinion of the Court, in which BURGER, C. J., and BRENNAN, STEWART, WHITE, POWELL, and REHNQUIST, JJ., joined. BLACKMUN, J., filed a statement joining in the judgment and in Part I of the Court's opinion and concurring in the result as to Part II of the opinion, post, p. 121. DOUGLAS, J., filed an opinion dissenting in part and joining in Part I of the Court's opinion, post, p. 121.

Sophia H. Hall argued the cause for appellant. With her on the briefs were William R. Ming, Jr., and Aldus S. Mitchell.

William E. Collins argued the cause for appellee. With him on the brief were A. Curtis Washburn and Charles F. Thomas.