In Brandenburg v. Ohio (1969), the Court ruled that speech advocating
illegal conduct is protected by the First Amendment unless it is likely to
incite “imminent lawless action.”

Epton v. New York (1968) declined to review the convictions of Marxist
leader William Epton, who said his convictions violated his First Amendment
free speech rights.

Feiner v. New York (1951) addressed the issue of whether speech that
incites a “breach of the peace” constitutes a categorical exception to the
First Amendment.

Hess v. Indiana (1973) overturned a demonstrator’s conviction and affirmed
that advocacy of illegal activity in the indefinite future is protected by
the First Amendment.

NAACP v. Claiborne Hardware Co. (1982) ruled that an economic boycott
constitutes a form of constitutionally protected expression akin to
traditional means of communication.

Before First Amendment protections were applied to state laws, the Illinois
Supreme Court upheld convictions based on speech in the Haymarket Riot in
Spies v. Illinois (1887).

In Stewart v. McCoy (2002), a case dealing with advising gang members,
Justice Stevens sought to clarify the First Amendment doctrine of
“incitement to imminent lawless action.”

Terminiello v. Chicago (1949) overturned on First Amendment grounds a
disorderly conduct conviction against a suspended Catholic priest for
making inflammatory public comments.