What would have happened if every Ukrainian wired all his money to Putin and signed contracts that they're his slaves now?
After all, Putin can move with impunity, because if we do anything, he nukes everyone, and the anwser to the margin-nuke question „Should we really start a nuclear armageddon for X?“ is always no, even if it‘s progressing from „Ukraine“ to „Romania“, „Italy“, „remaining EU countries“, „NYC“, „Washington State“, „Southern half of US states“, etc.
From a game-theoretical POV, any nuclear power is allowed to do anything as long as the marginal anything they are currently doing is small enough.
After all, Putin can move with impunity, because if we do anything, he nukes everyone, and the anwser to the margin-nuke question „Should we really start a nuclear armageddon for X?“ is always no, even if it‘s progressing from „Ukraine“ to „Romania“, „Italy“, „remaining EU countries“, „NYC“, „Washington State“, „Southern half of US states“, etc.
From a game-theoretical POV, any nuclear power is allowed to do anything as long as the marginal anything they are currently doing is small enough.