So, I've been thinking of what can be done about Iran short of giving them a non-aggression guarantee. Sanctions are the only response that I've seen on the table as possible reactions to an ongoing nuclear program. The common wisdom is that Russia and China would oppose such sanctions in the Security Council, so unified UN member state sanctions are unlikely. That leaves multilateral sanctions via another incarnation of a "coalition of the willing," not including Russia and China. But would such sanctions have teeth? If Iran could weather the sanctions, our negotiating position would be a shadow of its former glory.
Iran has 132 billion barrels in known reserve, and they produce 4 million barrels per day(mbpd), leaving them to export 2.5mbpd. China is a growing economy - if we take ourselves and much of the rest of the world out of the running for Iran's oil, they'll certainly see a price slump, but perhaps not an economic implosion that we'd be banking on. They have over $40 billion in foreign reserves and gold that's been built up over these last few years of skyrocketing energy costs. If China, or other oil hungry countries can take up the slack we leave, then our sanctions will accomplish little of nothing. The Iranian elite might not be able to order their Chippendale furniture from Europe anymore, and they might start using more of the 5 cent junk we're inundated with by China, but they'd survive it. I don't think it would be the tipping-point inducing regime change we hope it would be.