Israel, apparently, which stopped him from crossing the border into the West Bank, where he was scheduled to give a speech. Real democracies aren't afraid of ridiculous men like Noam Chomsky. Yediot, via Didi Remez:

The decision to expel Prof. Noam Chomsky from the border terminal in order to prevent him from lecturing at Bir Zeit University is an act of folly, part of a large series of follies in the recent period, which together could mark the end of Israel as a freedom-loving state of law, or at least pose a large question mark over this.

This decision is first of all patently illegal, since it stands in stark contrast to the most important ruling of the Supreme Court in the Kol Haam affair, in which it was determined that restricting freedom of speech is only legal if the statement is of a kind that could pose a clear and immediate danger to state security.  Truth is not dictated from on high and opinions and ideas cannot be supervised.  The best test of truth is the power of an idea to be accepted in the marketplace of ideas.

But in Israel, the government has already started to threaten freedom, at least the freedom of those who are perceived as others.  We have ceased to take an interest in what the others have to say, not to mention their rights to live here in a normal fashion.  We want them to get out of our sight.  We hound the others on the basis of generalizations, suspicions, prejudice or just because they are annoying.