Charles Krauthammer speculates about Iran's Green movement:
Assume you care only about the nuclear issue. How to defuse it? Negotiations are going nowhere, and whatever U.N. sanctions we might get will be weak, partial, grudging and late. The only real hope is regime change. The revered and widely supported Montazeri had actually issued a fatwa against nuclear weapons.
And even if a successor government were to act otherwise, the nuclear threat would be highly attenuated because it's not the weapon but the regime that creates the danger. (Think India or Britain, for example.) Any proliferation is troubling, but a nonaggressive pro-Western Tehran would completely change the strategic equation and make the threat minimal and manageable.
Again, it's worth asking where we get the idea that were the Green movement to succeed, it would bring to power a government that's congenial with Washington's view of how Iran should behave itself in the Middle East? It's quite possible that it could, but we don't know for sure and any assertions to the contrary are just that. Assertions. With little discernible basis in fact.
I would like to see the Green movement succeed - I think most in the West do. But that wish is born of a desire to see Iranians live without the oppressive yoke of their government, not because I think it's going to suddenly and dramatically transform Iran's views of its national interests. Consider that Russia went from a one party communist tyranny to a democracy without any serious strategic shift with respect to its security interests in Eastern Europe or its view of NATO.