Brandenburg v. Ohio · ¶44

This is, however, a classic case where speech is brigaded with action. See Speiser v. Randall, 357 U. S. 513, 536-537 (Douglas, J., concurring). They are indeed inseparable and a prosecution can be launched for the overt acts actually caused. Apart from rare instances of that kind, speech is, I think, immune from prosecution. Certainly there is no constitutional line between advocacy of abstract ideas as in Yates and advocacy of political action as in Scales. The quality of advocacy turns on the depth of the conviction; and government has no power to invade that sanctuary of belief and conscience.

U. S. Reports, bound volume
U. S. Reports, volume 395, at 444 (Library of Congress) · transcription: Caselaw Access Project
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