Seems we've heard most of those retorical speeches before, and provided there are some sense of reality left in Iran a nuclear strike on Israel wouldn't give them more than a short lived martyr-status in the arab world.
Given the size of Israel, and it's mixed population, a nuclear attack would most likely take out quite a number of moslems living in or around the targets in Israel.
And if a nuclear attack should in some way affect the holy places in Jerusalem, it could lead to the city being declared a fallout disaster end rendered habitated in the same degree as the suroundings of the Tsjernobyl nuclear plant...
Imagine the headlines in arab newspapers:
"The galant armed forces of Iran with the aid of Allah has wiped the jewish opressors out of Jerusalem, we will gather our moslem brothers to celbrate the victory in the Dome of the Rock, the doors will open in about 145 000 years as we have to wait for the radiation level to drop."
What really bothers me is that Israel has done stunts without green light from the USA before, on the assuption that it's easier to get absolution afterwards than blessing before.
An "amber light" could sound like "Go get them!" in Hebraic for all I know...