Well, now they can suck it. Our military could so easily sock the Russians if they tried to expand westward, but I'd rather watch the Europeans squeal in horror as the reds steamroll them.
There is no evidence of the Russians expanding westward.
Just holding Crimea, which is something we have known that they will do even if Nukes, Chemical Agents, and Biological Weapons are required ... since the Crimea War.
Ukraine was spun off as a separate nation on paper, while intended to remain a critical strategic resource as part of a political ploy.
But they were always going to retain it even if that requires total war.
You might read some of the many books we have on Russian Military thought. This stuff was required reading when I was in the Marine Corps (assuming that you ever wanted to make rank) and it is sad to see so many people that didn’t know this was going to happen and openly fantasize that Ukraine can come to a west that isn’t a devastated wreck of what it was before the global war trying to pry Ukraine from Russia will (not might) precipitate.
At the very least I hoped Americans in general would be smart enough to beef up our NBC capacities and prepare our cities and populace to survive such a conflict if the west chooses to go to the mat.