Only a few categories of speech are unprotected by the First Amendment:
- advocacy intended, and likely, to incite imminent lawless action, see Brandenburg v. Ohio, 395 U.S. 444 (1969);
- obscenity, see, e.g., Miller v. California, 413 U.S. 15 (1973);
- defamation, see, e.g., New York Times Co. v. Sullivan, 376 U.S. 254 (1964); Gertz v. Robert Welch, Inc., 418 U.S. 323 (1974);
- speech integral to criminal conduct, see, e.g., Giboney v. Empire Storage & Ice Co., 336 U.S. 490 (1949);
- so-called “fighting words,” see Chaplinsky v. New Hampshire, 315 U.S. 568 (1942);
- child pornography, see New York v. Ferber, 458 U.S. 747 (1982);
- fraud, see Virginia Bd. of Pharmacy v. Virginia Citizens Consumer Council, Inc., 425 U.S. 748 (1976);
- true threats, see Watts v. United States, 394 U.S. 705 (1969); and
- speech presenting some grave and imminent threat the government has the power to prevent, see Near v. Minnesota ex rel. Olson, 283 U.S. 697 (1931).
Is the classification of speech into one of these categories a question of law or question of fact? For example, if a defendant were charged with a crime based on his speech, could the judge bring the case to an early end by concluding that the speech in question was protected? Or must that determinations be left to a jury?
Does the answer change from category to category?
EDIT: I'm looking for answers with verifiable citations to the law.