Europe will be much better off if we can guarantee our own security. I'm not suggesting for something dumb like withdrawing from NATO without first having the next thing in place, but we need to be in a position where Putin (and his eventual successor) does not feel like they can push us around as much as the Americans will tolerate, which is precisely what Putin thinks.
We can and should be in a position where we push Russia around as much as China and India allows, and we dictate terms to them instead of cowering while they dictate terms to us. We should be in a position where if we say we are going to incorporate Ukraine into a defensive alliance that the Russians praise us and bow out of fear that we will take more of their things, instead of the reverse.