Something else that’s not been addressed, but was by a poster over on Michelle Malkin’s site, is that if you are willing to live with some significant risk while toting your nuke around, a Hiroshima type “weapon” is then much simplified and easier to make. As Wikipedia puts it “straightforward if not trivial to design”.
This makes Biden and Obama’s assertion that we still have plenty of time for sanctions to work, dubious at best. This may well be the #1 thing that Netanyahu loses sleep about at night: Who believes the more radical Iranians are really worried about the risk whomever might be working with the weapon might face?
Besides, we also have the example of North Korea to learn from: A wrecked economy and starving people didn’t keep them from obtaining The Bomb.
I wish Romney had simply asked his audience “Do you think America and Americans are safer in the world now, than 4 years ago?”
NK has taken the two track approach. In fact there is some speculation that at least two attempts we detected early in their process were either tests of the high explosives necessary to effect implosion that went wrong, or failed plutonium weapons tests in and of themselves.
The Iranians are all-in on Uranium. They would simply need to deliver several sub-critical masses of Uranium "by hand" to the target, then drive them together with C4. There are several simple designs. The most difficult calculation is actually how much shielding would you need in order to keep your couriers alive long enough to deliver it, and how many couriers do you need? I'm not an expert but I believe I heard a number of years ago that the exposed plutonium core of a nuclear weapon would kill you in about 60 seconds. Probably the same order of magnitude for fissile uranium. So, you need some amount of lead and lots of martyrs. No shortage.
When they have the refined product, for all practical purposes they have The Bomb.