We SHOULD have gone to war with Iran when their Copper Lance IEDs were killing our troops by the hundreds in Iraq, but we didn't. We should have gone to war with Iran when their proxies, Hizbullah and Hamas, made war upon our ally Israel in the summer of 2006, but we didn't. We should at least consider some form of warfare against Iran for propping up the Syrian dictator Baby Assad with gunboat diplomacy, but we apparently aren't.
Nukes are a different matter. Possessing them at home doesn't make you an automatic international pariah, or it shouldn't, anyway. No war with Iran over nukes.
We need to get this over to Iran: go ahead and build your Mullah-Bomb. Build a nice safe fort to put it in and hold prayers over it every Friday, if you must. Admire it, boast about it, even lie about it's power. Fine, all the members of the Nuclear Club do that.
What we THEN need to tell Iran is that joining the Nuke Club has one itsy-bitsy drawback: if you USE that nuke, you are then subject to nuclear retaliation. Annihilation. Turn your Holy City (Qom) to glass annihilation. On Friday evening during prayers annihilation. Make that promise believable. We USED to know how to make that threat believable, and it held off China and the USSR for years. It seems to have held off the Norks in recent years.
Mutually-assured destruction. Not high-tech, but proven nonetheless. It's a scalable concept, too. Works for one nuke or 10,000 of them.
It would help reinforce the MAD Doctrine if our peacenik President wasn't trying to disarm our own nuclear arsenal, and if the old USAF Strategic Air Command was reactivated, specifically with it's former purpose of being two of the three legs of the Nuclear Triad, but MAD is certainly viable, and even before nukes, the concept of MAD has been useful in international relations at least since the Greeks and Romans.