I personally believe that we're very likely to see at least 10 million dead in the Middle East within the next two decades, with an upper limit near 100 million. I do not believe pre-emptive action will be taken against Iran. I do, however, believe the extremist mullahs in Iran mean exactly what they say. They are steeped in an ideology that believes suicide/murder to be the holiest and most moral act possible. They have been diligent in laying strategic plans for an offensive Islamic War against Israel, America and the West. Plans backed by 25 years of action, and stated no less clearly than Mein Kampf. I believe that Ahmedinajad's talk of 12th Imam end-times and halos around his head at the UN aren't the ravings of an isolated nut, simply an unusually public (and unusually noticed) expression of beliefs that are close to mainstream within their ruling class. That class of "true believer" imams and revolutionary guard types have been quietly consolidating their control over all sectors of Iranian society over the last few months, and I do not believe anyone in the world today has both the will and the capability to stop them. A key pillar of The Bush Doctrine is about to fail.
In short, Katzman believes Iran will attain the nuclear sword and they will use it killing millions and possibly Islam in the process. And because the West doesn't have the will and Israel doesn't have the ability to do anything right now means the likelihood of far more bloodshed in the future.
Damnably depressing but worth reading.