The idea that a limited nuclear exchange is OK, even inevitable in this conflict, and that things will somehow magically go back to normal afterwards is ludicrous.
All leaders must know that any use of nuclear weapons will be met with the complete annihilation of their country. This is the ONLY sane policy.
Sure. That's why I'm saying that even if Putin uses one or few nuclear warheads, NATO should restrain itself and not use any, just beat Russian army in Ukraine purely with conventional and economic means.
MAD is only about the fact that if country is at existential threat it will respond by launching all nukes.
But neither US nor Russia is at existential threat when they lauch just a few at proxy targets.
Don't get me wrong, it's still an atrocity, but it isn't existential threat to those countries and probably won't trigger MAD.