Final answer:
KKK leader Brandenburg was acquitted in Brandenburg v. Ohio because his speech did not create an imminent danger to public safety or government interests, (option a) aligning with First Amendment protections unless speech incites immediate unlawful action.
Step-by-step explanation:
In the case of Brandenburg v. Ohio (1969), KKK leader Brandenburg was acquitted of an unlawful action because his speech did not create imminent danger to public safety or government interests. The Supreme Court ruled that the mere advocacy of the use of force or of violation of the law is protected by the First Amendment. It is only when such speech incites direct and immediate unlawful action that it falls outside of constitutional protection.
This decision underscored the threshold for what constitutes unprotected speech: advocacy must be directed to inciting or producing imminent lawless action and is likely to incite or produce such action. This doctrine is distinct from previous limitations on speech, such as those imposed by the Espionage Act of 1917 and Sedition Act of 1918, where speech presenting a clear and present danger could be restricted. The landmark ruling in Brandenburg v. Ohio liberalized the legal protections for speech, especially in context to symbolic speech and advocacy of hypothetical action.