Brandenburg clarified what constituted a "clear and present danger", the standard established by Schenck v. United States (1919), and overruled Whitney v. California (1927), which had held that speech that merely advocated violence could be made illegal. Under the imminent lawless action test, speech is not protected by the First Amendment if the speaker intends to incite a violation of the law that is both imminent and likely. While the precise meaning of "imminent" may be ambiguous in some cases, the court provided later clarification in Hess v. Indiana (1973) in which the court found that Hess's words were protected under "his rights to free speech",^[3] in part, because his speech "amounted to nothing more than advocacy of illegal action at some indefinite future time,"^[3] and therefore did not meet the imminence requirement.

The two legal prongs that constitute incitement of imminent lawless action are as follows:

Advocacy of force or criminal activity does not receive First Amendment protections if (1) the advocacy is directed to inciting or producing imminent lawless action, and (2) is likely to incite or produce such action.^[4]

The Court upheld the statute on the ground that, without more, "advocating" violent means to affect political and economic change involves such danger to the security of the State that the State may outlaw it. Cf. Fiske v. Kansas, 274 U.S. 380 (1927). But Whitney has been thoroughly discredited by later decisions. See Dennis v. United States, 341 U.S. 494, at 507 (1951). These later decisions have fashioned the principle that the constitutional guarantees of free speech and free press do not permit a State to forbid or proscribe advocacy of the use of force or of law violation except where such advocacy is directed to inciting or producing imminent lawless action and is likely to incite or produce such action.^[4]

• Hit Man: A Technical Manual for Independent Contractors
• Clear and present danger
• List of United States Supreme Court cases, volume 395
• Shouting fire in a crowded theater
• Threatening the president of the United States
• Abrams v. United States, 250 U.S. 616 (1919)
• Brandenburg v. Ohio 395 U.S. 444 (1969)
• Chaplinsky v. New Hampshire, 315 U.S. 568 (1942)
• Dennis v. United States 341 U.S. 494 (1951)
• Feiner v. New York, 340 U.S. 315 (1951)
• Hess v. Indiana 414 U.S. 105 (1973)
• Korematsu v. United States 323 U.S. 214 (1944)
• Masses Publishing Co. v. Patten (1917)
• Sacher v. United States, 343 U.S. 1 (1952)
• Schenck v. United States 248 U.S. 47 (1919)
• Terminiello v. Chicago, 337 U.S. 1 (1949)
• Whitney v. California, 274 U.S. 357 (1927)

• Siegel, Paul (February 1981). "Protecting political speech: Brandenburg vs. Ohio updated". Quarterly Journal of Speech. 67 (1): 69–80. doi:10.1080/00335638109383552.
• Reed, O. Lee (September 2000). "The state is strong but I am weak: Why the 'imminent lawless action' standard should not apply to targeted speech that threatens individuals with violence". American Business Law Journal. 38 (1): 177–208. doi:10.1111/j.1744-1714.2000.tb00287.x.
• Pew, Bradley (31 October 2015). "How to Incite Crime with Words: Clarifying Brandenburg's Incitement Test with Speech Act Theory". BYU Law Review. 2015 (4): 1087–1114. ProQuest 1837555055.
• Calvert, Clay (1 January 2019). "First Amendment Envelope Pushers: Revisiting the Incitement-to-Violence Test with Messrs. Brandenburg, Trump, & Spencer". Connecticut Law Review.

• Hess v. Indiana, 414 U.S. 105 (1973)
• Advocacy of Unlawful Action and the Incitement Test

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