The mere fact that escalation isn’t in the best interest of any of the parties doesn’t mean it can’t happen. If you don’t believe me, just ask Archduke Franz Ferdinand.
If it does happen, it will probably be the result of attacks by Hezbollah or pro-Iranian militias in Iraq or Syria which require a much larger American response than what we are seeing today. That, in turn, could cause the Iranians to participate directly in the war. Would America and Israel tolerate that without retaliation? Probably not.
If America and Israel contemplated attacking Iran at that point, they would have to consider Putin’s position. In years past, it would have been safe to assume that Putin would have acquiesced to an assault on Iran as long as he received something valuable in return. Today, however, conditions have changed; the Russians are tied up in Ukraine, but the Iranians are actively assisting them. Would Putin stand by and watch the destruction of his ally without threatening some form of escalation? If not, what could he do? Would he risk attacking NATO forces helping Ukraine? Would he send hypersonic missiles against the Israelis? Would he even consider using nukes against either the Americans or the Israelis?
Let’s hope we never find out.