constitutional law

Advocacy of Illegal Action

A category of speech unprotected by the First Amendment.  For many years, the constitutional rule famously was that speech was unprotected if "words used are used in such circumstances and are of such a nature as to create a clear and present danger that they will bring about the substantive evils that Congress has a right to prevent."  Schenck v. United States, 249 US 47 (1919).

Necessary and Proper Clause

Under Article I, Section 8 of the Constitution, Congress has the power "to make all Laws which shall be necessary and proper for carrying into Execution the foregoing Powers, and all other Powers vested by this Constitution in the Government of the United States, or any Department or Officer thereof".

See the CRS/LII Annotated Constitution on the Necessary and Proper Clause.

Commercial Speech


Speech which promotes at least some type of commerce.


Under Central Hudson Gas & Electric v. Public Service Commission, 447 U.S. 557 (1980), commercial speech is less protected under the First Amendment than other forms of speech. 

Absolute Privilege


If a statement is made in certain contexts or in certain venues, the First Amendment may give the speaker an absolute defense to a charge of defamation.  This privilege usually only exists in the government context; for example, sworn testimony in a judicial or legislative hearing is privileged.




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