If the survival of their country was at stake, of course the Israelis would use their nuclear weapons. The United States would do the same.
No kidding, survival is survival. Look, if any sensible and decent person was faced with a choice of themselves and their families being killed by an axe murderer, they'd be fully justified in pulling out a gun and killing the SOB. Nukes are just the national equivalent of a 12-gauge.
That being said, using them is a last resort for any sane and moral nation. Israel has other options. Of course, if the US is going to stand in the way (not by failing to cooperate, but by actually saying "no, rely on negotiations" even as Iran reaches the point of no return on getting sufficient nuclear material for a bomb), then Israel will have fewer (or no) options but to nuke Iran.
The simple fact is that Israel is the canary in the coal mine. Condor51, do you really believe that if Israel ceased to exist that the Arabs/Moslems would suddenly stop hating us? Israel is an excuse, an easy one for them. Remove it, and another excuse will pop up within an hour. We are definitely next on Iran's "needs to be nuked" list.
I'm not so sure of that.
I think the people would have to force the government to take action.
Tar and Feather futures are looking good.