The revelation in the latest National Intelligence Estimate that Iran abandoned it's nuclear weapons program in 2003 leads me to several questions, the principle one being; Why 2003?
The answer that leaps to my mind is that Iran was rushing toward a nuclear weapon because Bush had declared that our invasion of Iraq was to prevent just such a development by Saddam Hussein. When Iran heard this, it would not be able to help noticing that no one was invading North Korea which was believed to already possess such weapons. The obvious conclusion of everyone in the world except George Bush was that countries opposed to the US were in danger of invasion unless they figured out how to build the Bomb, and quick!
Come Fall 2003 and the invasion of Iraq is in full swing. Bushies might claim that we had frightened Iran into abandoning their WMD program by the shear awe of our military operations. That of course would be assuming that our military operations, however brilliant, were successfully controlling the country and overcoming the Baathist Plan B - guerrilla warfare. By that time, it was becoming clear that the US occupation was inept and the US military incapable of threatening any other country for a good long time.
If you are not convinced that the US struggles in Iraq were discernible in 2003, then you must admit they were glaringly obvious by 2004/2005. If Iran had been frightened into abandoning nuclear ambitions by Shock and Awe in 2003, then they would have been able to start back up in 2005 with no fear of invasion by the US. On the other hand, if, based on the evidence on its doorstep, Iran calculated that the US was not a military threat to the regime then the urgency to gain nuclear weapons disappears and other means for regional influence and protection become more attractive priorities.
What this NIE shows most of all is that the Crazy Man theory of international diplomacy is bankrupt. If it can be applied to Kim Jong-Il, that is its limit. As for the rest of the world, even the meanest despot is working from a position of self-interest that may be potentially understood and influenced. We will not always win or get everything we want in the world but basing policy on the proposition that our adversaries are "crazy" is a recipe for unmitigated disaster, failure and decline.