Would dropping a nuke on Jerusalem be likely? http://www.nukefix.org/weapon.html Seriously?
What would happen if Iran used nukes on Israel? Israel and the US would bomb Iran back to the stone age. There isn't the remotest possibility that Iran could take out all of Israel's nuclear weapons there is good evidence that a good number of them are based on submarines.
We went to war with Iraq because they were supposed to have weapons of mass destruction.
Hopefully, we will not make the same mistake with Iran.