Just read an interesting article by Dennis Ross concerning the choices the next President will have to make regarding Iran. It is estimated that, sometime next year, Iran will have refined enough uranium to the 20% level that they could, quite quickly, enrich it to weapons grade and deploy it on a weapon.
The problem with this, of course, is that Iran has no weapon system suitable for, or capable of, carrying a nuclear warhead. Nor do they have the highly technical expertise necessary to create a nuclear warhead, even if they had the weapons grade uranium. Could they build a dirty bomb and give it to terrorists? Sure, but they don't need weapons-grade uranium for that. The 20% they have would do just fine.
For either a deterrent or an offensive weapon, Iran will first need the technical expertise to create a warhead, and then they will need to create the delivery system, something that will not become possible next year. In fact, according to Reuters, Shannon Kile of the EU Non-Proliferation Consortium estimates it will be at least several years before Iran could develop this technology.
Since the Islamic Revolution, Iran has steadily built its own arms industry, declaring itself in recent years to be "self-sufficient" militarily. They build their own missiles, tanks, ships, and even fighter jets. For a list of Iranian weapon systems, see here. It's an impressive list, really, and I'm sure it is rather daunting to Iran's regional nemesis Saudi Arabia. But what you won't find in that list, and isn't even under development, is a missile capable of carrying a nuclear warhead. Despite what they evidently want the American public to believe, you can't just cram some uranium powder into a conventional warhead and call it a nuke. The warhead itself must be developed using inert ingredients to simulate the uranium gas, fitted to a missile designed for a heavier warhead, and tested strenously. Otherwise, you end up with a nuclear explosion inside your warhead assembly plant, or in midair shortly after launch.
Don't expect this fact to keep President Mittens (or a re-elected Obama) from attacking Iran based on the nuclear enrichment level. The military-industrial complex is hungry, and must be fed more American blood. Our only hope is that men and women of good character will somehow put a stop to the madness before the bombs begin to drop.