In 1917, in a case related to the Russian Revolution, Masses Publishing v Patten, Judge Learned Hand wrote an opinion that "the government may prosecute words that are 'triggers to action' but not words that are 'keys of persuasion.'" In Brandenburg v Ohio, the Supreme Court expanded on this--in a ruling favorable to the Ku Klux Klan--holding that "the First Amendment allows punishment only of subversive advocacy calculated to produce 'imminent lawless action' and which is likely to produce such action."
The Incitement Test (Brandenburg) 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.So, if speech is a trigger to imminent action--it is incitement, and may be banned.
