While in general I don't agree with balaks in terms of what could and should be done to give Putin a way out, I really don't understand how anyone can be so sure nuclear weapons are off the table.
Every major event of this sort in history is unlikely to happen, until it actually happens. We are rationalizing Putin right now, the way Hitler was rationalized in 1930s (well, my wild guess is he was). It's not like history isn't littered with thousands of crazy leaders, we have no scale or method to measure just how crazy they are until they do their shit.
Still, as I said before, I don't agree with balaks. I don't really see what world should do other than what it's doing right now. We are all deep in this (obviously count myself as anti-Putin too) and no way should anyone give up. Even at the cost of nukes. When Kingdom of Yugoslavia's government signed pact with Nazi Germany in 1941, partisan protests immediately broke out and a saying "Bolje grob nego rob" was coined. It means "Better the grave than a slave" and coincidentally, it rhymes in both languages.
I'm not really scared that our lives would be endangered, but even if they were, should we just drop our heads down and let ourselves be run over?