Gary Sick games the looming October 1 negotiations:
What if Iran got a bomb? Well, unless they buy one intact, the process of actually moving to weaponization is likely to be noticed, so one must ask what happens between the moment when they decide to proceed to a bomb and when they actually have it. That period, which is apt to be several years, would be the true case of the ticking time bomb, and that would be the moment for consideration of extreme pressure tactics, probably with very wide support in the international community. Iran knows this, and that is itself a disincentive for them to proceed.
The real purpose of negotiations, in my view, is to build a system of monitoring and inspections that will (1) provide maximum early warning of a potential future Iranian decision to “break out;” and (2) insure the maximum possible interval between that moment and the moment where Iran could actually have a bomb. Iran has said on several occasions that it is willing to accept such an enhanced inspection regime, but it will no doubt insist on a price. That, I think, is what the negotiations should be about.