Some thoughts from Les Gelb:
I think there’s no chance of forcing or persuading Iran to abandon its uranium enrichment program. The issue is can we forestall their developing and deploying nuclear weapons, and I think we can. We can’t stop a peaceful program. We’ve already conceded such programs for North Korea, for heaven’s sake. We’ve been prepared to give them two light-water reactors that can produce weapons-grade material. And we’ve rewarded India and Pakistan for going nuclear. Plus, Israel is a nuclear power.
In my book I stress that it’s futile to set unattainable goals, though politics and ideology push Washington in that direction time and again. So, let’s begin the process of negotiations with Iran. It will be hard, long, and painful. But here’s my guess: Iran as a society is more middle class and more prone to democracy than any other country in that part of the world. Within ten years, Iran will be our closest ally in the region.
That's my guess too. Getting to that without provoking an apocalypse will be the hard, long painful part.