More likely Iran will launch a nuke from a floating platform off our coast. Also, with a limited amount of fissile material it is likely they'd try to get the most bang for their buck and set off the nuke in the ionosphere so as to destroy the electronics across a wide swath of America (HEMP attack). A Hemp attack would have a far wider impact than the nuking of one American city.
Even my 15-year-old truck would be useless after a HEMP attack. Yours too, if it has electronic fuel injection or any of computer-controlled systems.
This is what I fear, and what I prep for. Mentally, I can adapt to an environment where the laser on my rifle does not work and I must shoot terrorists using iron sights.