First, for all of those who have never been East of the Hamptons, it is NOT The France, The Germany, The Poland, and not The Ukraine. It is Argentina and The Argentine. But not The Ukraine. It is The United States but not The Canada.
Now on to Russia and Ukraine. Having been in both spots, and not being a George Kennan, only having companies and business partners, Russia does not like instability on its borders. I recall once meeting with a banker from London and one of my "associates" in Moscow when we discussed building a fiber across Belarus. The banker asked what about the political instability in Belarus. My Russian associate slammed his fist down and said he will send in tanks. The banker was a bit concerned as how best to fit that assurance into his due diligence report. But in nutshell that is the Russian way.
I also recall a meeting I had with Deutsche Telecom in Moscow. It was an endless ride from my hotel to the outskirts. I went to the executive conference room and it had a beautiful view of some monument below. When the head of the office came in I was fooling enough to ask what the monument was. It was German tank, it was as far as the Germans had gotten to Moscow. They DT office was allowed to get across the street but no closer. Russians have a long memory, whether it is Napoleon or Hitler. They want a buffer.
Thus an unstable Ukraine is a concern. It all depends on how one vies the current instability. Is it to get a better Ukraine or a Western organized coup. I do not suspect the latter but given recent releases from Snowdon one could guess from the past this could be their view. Thus Ukraine must remain a buffer.
So what should the West do? Good question. It depends on how far Putin will push. One could imagine that he wants to recover Haigia Sophia in Constantinople, I mean Istanbul. That could make him a Saint Vladimir in the eyes of many. It would also resolve the straits passage problem. It would also remind us of 1914.