Yak they may be dumb but they aren't stupid, they hold most of the aces at the moment. Now suppose the US bombs these nuclear targets, is that really going to seriously hurt Iran's overall ambitions? I doubt it. It may set back their nuclear capability a year or two, but that may be a small inconvenience to the turmoil it unleashes in the middle east and oil markets.
What do you think is the best course of action for the US? We can talk about the rights and wrongs of Iraq ad nauseum (and we have) but the mess in Iraq really has given Iran a massive free kick.
