[JumpCrisscross]

> no de-escalation mechanism? Maybe through the UN?

Possibly. Israel and Iran have friends in Moscow, so the usual Sinorussian veto party could be sidestepped. But this would require Russia extending its nuclear umbrella over Iran. That, in turn, gives Putin a say in Iran's extensive extra-territorial meddling. Tehran may figure they can get their own nukes out of Russia for a cheaper price.

Tellingly, America has only extended strategic ambiguity to Israel, the same as we give Taiwan, not a red-lined nuclear umbrella like we do to NATO or Japan. This doesn't seem like a problem great powers care to resolve.