As Didi Grinstein surely knows very well, Israel's existence is guaranteed by nuclear weapons. No outside force can threaten Israel's existence. Only Israel itself can threaten its existence. The idea that "delegitimation" could pose an existential threat to Israel is ludicrous. The only thing that threatens Israel's existence is military force and/or nuclear weapons. The military power of Israel's adversaries is permanently neutralized by Israel's nuclear deterrent. The only thing that could conceivably endanger Israel's physical existence is a nuclear attack carried out by non-military means: i.e. by a non-state terrorist group. That - while highly unlikely - admittedly *could* happen, and Israel should take measures to prevent it; but it has nothing whatsoever to do with campaigns of "delegitimization" of the type Grinstein speaks of here.
Palestinians report IDF airstrikes on Islamic Jihad targets in southern Gaza Strip (Haaretz)
from the article: Comment / Israel delegitimizers threaten its existence