[gambiting]

>>At this point, neither intervention nor non-intervention is likely to prevent this. It's entirely likely that if Putin loses this assault, or faces an intractable insurgency, he could launch nukes out of a desperate attempt to save face. He's old — at this point, only the reputation he leaves behind is what matters to him, and it's clear that he wishes to be remembered as a fearful and powerful figure. What better way to do that than nuking someone?

I do agree that if he's pushed against the wall he can nuke one Ukrainian city saying it was the hideout of the rebels or whatever, effectively sending a message that he's not afraid to use nuclear weapons, without directly attacking a NATO state. I can only assume that at that point whatever is left of Ukrainian government would voluntarily step down to prevent further destruction.

You're right that he's a madman, and any sort of logical strategy just doesn't apply here.