Whether Chicago could constitutionally punish speech under a construction of its disorderly-conduct ordinance that allowed conviction because the speech stirred anger, invited dispute, or created unrest.
Holding
No. The ordinance, as construed and applied through the jury instruction, unconstitutionally reached protected speech.
Reasoning
The Court treated the trial judge's definition of "breach of the peace" as an authoritative construction of Illinois law. A state court's construction is binding on the Supreme Court just as if the limiting or expansive language had appeared in the ordinance itself.
Free speech has a central democratic function: it permits the debate and exchange of ideas through which government remains responsive and peaceful political change can occur. Speech may properly challenge prevailing beliefs, provoke disagreement, unsettle audiences, and even stir people to anger.
Although freedom of speech is not absolute, the government may not punish provocative expression merely because it produces public annoyance, unrest, or dispute. Punishment requires a likelihood of a clear and present danger of a serious substantive evil that rises far above ordinary inconvenience, annoyance, or unrest.
The instruction allowed the jury to convict Terminiello on precisely the impermissible grounds that his speech invited dispute, stirred anger, or produced unrest. Such a rule would permit government or dominant community groups to standardize ideas by suppressing expression because of its disturbing effects.