Incitement
Brandenburg test
Speech directed at inciting imminent lawless action, and likely to actually produce it — a narrow, specific standard that protects most advocacy of illegal action in the abstract, reserving unprotected status for speech that crosses into direct, imminent incitement.
True Threats
Genuine threats of violence
Statements that a reasonable person would understand as a genuine expression of intent to commit violence against a specific target.
Obscenity
Miller test
Material lacking serious literary, artistic, political, or scientific value, evaluated under the specific Miller test framework — a narrower category than many people assume, since material must fail all prongs of this specific test to qualify as obscene.
Defamation, Fraud, Fighting Words
Rounding out the unprotected categories
Defamation (false statements harming reputation), fraud (deceptive statements causing harm), and fighting words (speech likely to provoke immediate violent response) complete the core list of unprotected categories.
💊 Time, place, and manner restrictions are a genuinely distinct concept from the unprotected-categories list above — government CAN restrict otherwise-protected speech based on time, place, or manner, but only if the restriction is content-neutral, narrowly tailored, and leaves open alternative channels for the speech.