Chomsky's chat at WaPo.com had a great thought of Chomksy's on the limits of free speech:
Lancaster, U.K: What do you feel are the limits to 'free speech' given the arguments recently over racial hatred and religious intolerance?
Noam Chomsky: My feeling is that the Supreme Court reached a reasonable standard of protection of speech in the 1960s, a standard higher than any other country in the world, to my knowledge. In brief, speech should be protected up to participation in imminent criminal action. So if you and I go into a store to rob it, and I say 'shoot,' that's not protected. Like all judicial decisions and legislation, this leaves plenty of gray areas, including many of great significance that are rarely discussed: advocacy of imminent war crimes, such as aggression, for example. I think we would all agree that such speech should be protected, despite the often horrific consequences, but it's worth noting that that stretches the doctrine to its limits.
The obvious rip was Chomsky referencing Bush's talking about how we were going to, and did, invade Iraq (and possibly Afghanistan, too). Invading another country is known in international law as 'aggression' - or, 'the supreme international crime' - a war crime, to be sure.
Should we have arrested Bush on the spot when he started talking about invading Iraq? Chomsky says, 'no' - but just barely on the 'no' side of that free speech situation. So, if Bush should not be jailed for calling for the committing of 'the supreme international crime', then the bar for free speech must be set pretty high.