An article in The New York Times talks about Tony Blair’s new plans for attacking Islamist terrorism. According to the Times, "In a 12-point list of measures, Mr. Blair said Britain planned as of today to broaden the grounds for deportation to include ’fostering hatred, advocating violence to further a person’s beliefs or justifying or validating such violence.’" The article misleadingly contends that the "British moves, part of an ongoing debate about the balance between civil liberties and national security, seemed to nudge Britain closer to the hardline attitudes against perceived extremists that emerged in the United States after the Sept. 11, 2001, attacks."
Actually, the American standard for violent speech is much more liberal. In a case that remains the foundation for how courts think about such speech, Brandenburg v. Ohio (1969), the Warren Court overruled many years of precedent and legal tradition and held that advocating violence against a legitimate government or its officials is protected under freedom of speech. According to that decision, speech can only be punished when a person incites someone else to "imminent lawless action" that is likely to happen under the circumstances (for example, telling an angry mob gathered in front of a city hall occupied by officials that "You should string up these infidel dogs right now!"). Until that point, government is powerless to intervene.
So far in the war on terror, the problem of violent advocacy has not mattered much in the US because we have been able to prosecute terrorist cells based on their actions under anti-conspiracy laws. But if the problem of radical imams preaching violence ever surfaces here, American authorities will be powerless to act directly, at least according to the Supreme Court’s current view.
Maybe this is the price we pay for free speech. But contrary to what many Americans might think, this is a new view and it is far from clear that it was the original meaning of the First Amendment.