I think any attempt to stop them will only result in delay. Attacks against their right to develop such weapons will only feed their paranoia that the best way to defeat such threats is by getting the weapons they want. Threats are counterproductive.

I've been re-reading Barb Tuchman's book, _The March of Folly_. In the portion on the American revolution she talks a lot about British paranoia about allowing the colonies to make their own decisions. One fear was that the colonies might begin to favor France. The majority in the British govt sought to use coercion with the punitive legal measures and eventually force of arms. Sure enough, like a jealous lover, their paranoia only served to bring about the thing they feared - a colonial alliance with France.

I think any attempts at coercion - political or military - will server only to drive the Iranians deeper into their paranoia which will result in the them gaining the object of our own paranoia. The only form of coercion that might work would be a total takeover of their country and I don't know anybody who thinks that would be an easy task.

As for the oil. I'm not certain they would cut supplies. They may reduce them but I doubt they would cut off the prime source of their money for funding whatever defense they think they need to fund. The greater they perceive the threat, the more funding they will need. Stopping the export of oil would hurt their interests as much as us I would think. But, also as in Tuchmans' book, governments are prone to choose courses that are a detriment to their own self-interests.