Seditious speech is speech directed at the overthrow of government. It includes speech attacking basic institutions of government, including particular governmental leaders. Its criminalization dates back at least as far as the Alien and Sedition Act.
According to John Cohan, "A delicate line can be crossed, whereby lawful criticism of government may become seditious speech, where associating with others in robust criticism of government may become subversive activities punishable by law". The Brandenburg v. Ohio U.S. Supreme Court decision maintains that seditious speech—including speech that constitutes an incitement to violence—is protected by the First Amendment to the United States Constitution as long as it does not indicate an “imminent” threat.
During World War II, U.S. President Franklin D. Roosevelt pressured Francis Biddle to prosecute seditionists, but Biddle declined, believing it to be unwise. Today's anti-war activists are not prosecuted for seditious speech.