This is where we start to reach the technological problem. Once you have advanced nuclear reactors, you have nukes even if you don't have nukes, because building one has become a trivial enough task in the modern era. Hence why you start seeing "all-but-nuclear" states being included on maps of the nuclear club (South Korea, Japan, etc.).
Now that would be news to me, especially given the resistance in Japan to nuclear weapons.
But at this point they barely have enough weapon grade material for 6 warheads, if they distribute it optimally, hardly a destructive force.
I'd like to see the President use that argument in a post-nuclear war world: "See? I was right! I said I handled it, and I did! They only could nuke us six times! Ha! I mean, it sucks to be New York, San Francisco, Los Angeles, Washington DC (thank god for the Presidential bunker amirite?), Dallas, and Boston, but we sure nuked
them pretty damn well! And that is why you should vote to re-elect me: I stand for statistical advantages."
The other problem with Nuclear Iran is it forces the US to make some very hard choices regarding their stability. Pakistan and North Korea are probably the two most unstable countries to possess nuclear weapons. Both have very large countries heavily invested in them, the US and China respectively. With Pakistan, the US will never be able to wipe their hands of them, because if they collapse all of the nuclear infrastructure (and the nukes themselves) will be very vulnerable to militants of all stripes, anyone else who might want them, and serious accidents. The US is stuck propping them up (and China to North Korea) because nuclear weapons in a country consumed by chaos is simply too volatile.