Give me a fucking break, dude. Israel doesn't believe Iran would nuke them any more than I do. The reasoning given for their pre-emptive strike is 100% complete and utter bullshit, and every serious person in the world fucking knows it. The true goal is and always has been regime change. The nuclear program is a red herring and you should be smart enough to recognize it.
You should ask yourself if you would be this concerned if Saudi Arabia possessed a nuclear weapon, considering they A) areone of the two main countries that we're doing this at the behest of, and B) they have literally attacked us in deadly fashion this century. If your answer is no, you should take that as a major clue that you need to re-examine your world view.
I'm not even saying the true goal is a bad one. Obviously, of course it would be a big positive if Iran were no longer run by extremists. At least then one of the countries in this fucked up devil's 3 way wouldn't be. We (and Israel) have to lie to the world about it because regime change is not considered adequate reasoning to unilaterally attack a country by any measure of international law or decorum. Period, end of story.