If Iran does develop nuklear weapons, they still won't have a delivery system that could send that bomb to mainland US. Their only practical targets are Israel or other nations in the region that are US allies. Iran has to know that Israel has no reservations about a first strike and will do anything to prevent a Iranian first strike capability.

Iran will only be able to build a small arsenal of Nukes and will be very releuctant to shoot the entire wad if they sense an invasion. Even if Iran was able to vaporize every US unit in the region, they'd still become a glass factory due to overwhelming US nuclear superiority.

I'm thinking all this talk by Iran is to create a financial compromise that helps them deal with some serious demographic problems their nation is facing. They have a giagantic population of young people that are out of work and are restless. Iran is now distracting this population from their problems with beligerence toward the West, but needs them to eventually be productive before widespread social unrests overthrows the mullahs. If a supposed nuclear showdown brings about negotiations that begins to intergrate Iran in the world economic system, then its a win for everyone.

If Iran is intergrated into the world economy then they'll be less willing to risk nuclear warfare with israel and peace will be upon everyone. Praise be to Allah!