Part of me wonders what Putin's plan is, in that sense.
If he annexes Ukraine (which isn't out of the question), then congratulations, he's now bordering four NATO countries (Romania, Hungary, Slovakia, Poland).
If he creates a puppet regime (also not out of the question, and more likely), then his satellite state is still bordering those two countries.
If he annexes the breakaway regions and/or eastern Ukraine, then the western part has even more incentive to join NATO.
Like, what's Putin's endgame here? Because it's clearly not "peacekeeping," nor is it "securing peace" in eastern Ukraine. Because either he's bringing the borders of Mother Russia up against NATO, or he's giving NATO and whatever remains of Ukraine all the more reason to treat Russia with hostility.