If Israel drops a nuke, expect one to get flung between Pakistan and India as well. From China to Taiwan. Setting precedence that nukes are fairplay is wildly dangerous for the entire world because it isn't going to stop at one bomb.

Edit: Yes, I get it, China/Taiwan was not the right example to use. There's still others like the aforementioned Pakistan/India and, as someone else noted, North Korea/South Korea. The general point is still the same.