Another option for Israel, that has been mentioned, is the Jericho EMP bomb that would destroy all of Iran’s electrical infrastructure without much human casuality. It would throw Iran back into the Stone Ages.
Link: http://www.israelnationalnews.com/Articles/Article.aspx/12017
Yes, but those facilities far underground would be hardened against such an attack—as would underground comm. it would set them back, but not far. Cut off the head and drop in weapons for the population.
It would be over in a week.