If your enemies are coming for you in the morning, you'd best go and get them tonight.
Iran has declared itself at war with Israel many times, and not one but several Iranian leaders have said that they want a nuclear war, because they can survive it whereas Israel can not.
To let these people get their hands on a nuke is the worst mistake Israel could make.
When will people realize that we are already facing a war,
the only question is, will it be on ground of our choosing,
or theirs?
If Iran already has a nuclear weapon, which I think they do, then Israel nuking Iran would be the worst mistake they could ever make.