Putin has made it plain in his speeches in recent years that he wants to put together the old Soviet Union or the old Russian Empire that the Soviet Union inherited. That horse is out of the barn. Estonia, Latvia, Lithuania, Georgia, and the Ukraine do not ever want to go back into the USSR. Nor Poland under the Russian thumb or any of the former east European nations.
Nukes are the biggest problem. We have a NATO contract that if any NATO country is attacked, all go to war against the attacker. Problem is, like Trump said, some NATO countries aren't spending the 2% on NATO military they are supposed to. The only ones who were was England and the new eastern European members.
Russia or Putin has threatened to use Nukes. Where does that put us? We are a founding ally of NATO. If Biden had any sense, he would try to force Russia and Ukraine into talks, and have a neutral country like Switzerland or even India monitor elections in the affected areas. Whatever the people decide, Russia and Ukraine have to agree with. Why is it no one except Israel has tried to get them to talk?