If Putin decides to escalate to nukes as a final act of failure then the de-escalation would be the complete annihilation of Russia as a country. In minutes.
The idea of getting away with a tactical nuke strike is insane.
to strengthen their negotiation position "We give you back X, you give back Mariupol"
> complete annihilation of Russia as a country
you think US would die for some village in Ukraine? They were plenty of US politicians and generals which were against nuclear umbrella for West Germany.
If the Ukrainians can push Russians back why wouldn’t they do the same everywhere? Crossing the border becomes an act of aggression, only Russia has acted aggressively here. Everyone else is trying to avoid conflict.
If Russia detonates a nuke in Europe the entire country will be obliterated immediately.