an existential threat to Russia, then you would THINK that he is just saber-rattling with his veiled threat of using nukes. Yes, that's a dangerous gamble to act on the belief that Putin won't use nukes, but remember the hard calculations Kennedy et al. had to make during the Cuban Missile Crisis.

With that in mind, I think NATO should tell Russia to get out of Ukraine NOW or it will indeed make Ukraine a NATO member. Demand an immediate cease-fire and give Russia a deadline to leave Ukraine. If they violate the cease-fire or fail to meet the deadline to leave, then do it: make Ukraine a NATO member and immediately flood the country with soldiers from all NATO countries and begin providing military air support to Ukraine to enforce a no-fly zone.

We need to shut them down. But how?