The real ramification of Iran getting nukes that we'd have to contend with on a daily basis is less that some wingnut might lob one at TLV, or SEA or BOS (although that's more possible than with other nuclear states). The reality is that, somewhat like DPRK, they'd use the nukes as a shield to enable lots of really bad behavior and malign influence in the region. It would all be very destabilizing to the ME, and other regional actors would acquire their own nuclear weapons (some have already made all of the arrangements, it would happen in days, not years). That would be fun.

As Hammer said: U Can't Touch This!