In light of Sagan's emphasis on nuclear weaponry, I thought I'd link to this article, in which Iran insists that it isn't devloping nuclear weapons, but vows to "respond to any blow with double the intensity". Of course, this article reminds us that even if Iran does just devlop nuclear power plants, it's still dangerous.
Sagan argues that the United States fear countries like Iran developing nuclear weaponry because of ethnocentric views. I disagree; I think we might be just as nervous about Canada suddenly developing a nuclear arsenal, especially if they were being secretive about it. (Put Canada half-way around the world, and make them not entirely friendly to the U.S., and I think you'd have exactly the same fears.)
Of course, my inner hippy thinks the problem here is not that Iran might have bombs, but that we seem awfully eager for an opportunity to blow them up first.