We, the USA, with or without the support of the UN, tell Iran, North Korea, and any other country developing nuclear weapons that to use them in an offensive attack means that they will receive in return, within 24 hours, thousands of non-nuclear weapons in return, at the least. Their country will be considered a free fire zone, where we can go in and take out all their planes, tanks, missile sites, etc. In short, bomb them into a defenseless position, and then step back and let their immediate neighbors have their way with them.
Back to the original question, I suspect that Israel has enough neutron bombs to blast a dead zone for several hundred miles into their neighboring enemy's territory, as well as enough regular nuclear bombs to reach the major cities of any country that attacks them, and will use them in their own best interests.
Pretty much what we would do, I think, if someone attacked us with a nuclear weapon.
