Iran is a conundrum.
We can't let Iran get the bomb: They are simply to crazy. MAD worked because the soviet leaders could be trusted to not do something that would destroy the dream of worldwide socialsim. The Iranian leaders would see it as martyrdom. They are the avowed enemies of Israel, the US, and the entire non-muslim world. They also sit on and in close proximity to most of the worlds oil reserves. By possessing the bomb they could invade and exercise hegemony over the entire region and keep the world at bay. An Indian general said after Desert Storm that the lesson was don't tangle with the Americans unless you have nukes. Iran wants nukes because they want to tangle with us.
We can't invade: I just don't see how an invasion, or even a limited bombing campaign would do any good. They have certainly learned from the Osirik disaster when the Israelis took out Saddam's nuclear ambitions in one swift strike. Their facilities are distributed and hardened and secret. Absent another 9/11 type attack , the American public would not support another invasion looking for WMD. That was the most unfortunate failure of the Iraq war. The most publicized purpose for the war, turned out to be false. Now any discussion of war to remove the Iranian nuclear ambtion will be lambasted in light of the failure to find wmd in Iraq. And the American public has no desire for another occupation.
The other ticking clock in Iran:
Regime change. That is what everyone is hoping/waiting for. Everyone is hoping that the much hated regime will finally be toppled by the young, restless, and freedom loving populace. The actions of the new president shows that those are genuine fears for the regime. He has removed several members of the military hierarchy. There has been brutal suppression of all dissent. Unfortunately, the rest of the world has done almost nothing to help support any democratic movement in Iran.
So the question is which clock will go off first?
Will there be regime change before there is a bomb? Do we have good intelligence on how far along the bomb is? Can we trust any such intelligence in light of the failure to find wmd in Iraq? Glad I am not President/Prime Minister. The world is starting to bear eerie similarities to 1914 and the 1930s.