To the extent that Israel does face threats, like from say Hamas or Hezbollah, those are threats that do not jeopardise Israel's existence.
Israel has a sizeable nuclear arsenal and could retaliate if it were attacked.
The thing that makes countries want to pursue some kind of nuclear deterrent is precisely the fact that they feel threatened.
Well, a nuclear-free zone in the Middle East would be a wonderful thing.
Our Cuba policy didn't make much sense during the Cold War and makes even less sense now.