The average Ukraine flag waving dolt in the U.S. who thinks Putin just decided to invade Ukraine on the spur of the moment doesn't seem to understand that this has been in the works since 2014 and a really a lot earlier. If you haven't read it yet, you should read this:
We have been poking at Russia for a bunch of reasons for years and now are acting like this came out of nowhere. It didn't. Meanwhile we seem to be about to see a major shift and the big showdown, not in Kiev where everyone is paying attention, but in the breakaway republics which have been the target all along.
The Zman usually has some good analysis and it appears that the Russians have 150,000 troops for the big fight and the Ukrainians only 70,000. I don't know where he gets that so I am taking him at his word. Should Russia succeed in locking down the breakaway regions and getting their land corridor to the Black Sea, all that is left is the agreement for Ukraine to stay out of NATO which Ukraine has pretty much agreed to and the recognition that Ukraine isn't getting those eastern parts back and that's the ballgame.
Two other factors.
One, far from undermining Putin this conflict with the West seems to have solidified his position. We see the conflict from the perspective of Vodka Man Bad posts and Ukrainian flags in social media profiles but in Russia it seems to be just more Western chauvinism against Russia, a people who have always thought of themselves as apart from the rest of Europe. This is an interesting piece on how actual Russians, distinguished from armchair anonymous bloggers in America who don't know shit, are thinking about the war:
For Russians it seems they see Putin as perhaps a cold hearted bastard but he is their cold hearted bastard. Don't underestimate how seeing someone else shitting on you can make you rally around your leader.
The other factor is that Russians are people used to deprivation and hardship so while the sanctions have hurt them, they seem to be hurting the West a lot more and we are no longer people with any ability to deal with even the mildest of inconvenience. Time will tell if it was a death blow but it certainly looks like it might be a major blow to U.S. global hegemony. The world runs on cheap oil and Russia provides a lot of it, and selling it using something other than the U.S. petrodollar is a major gamechanger. The haphazard response from the U.S. has made it that much easier for Putin to get us to kneecap ourselves to get back at Vodka Man Bad.
All around this is a bad situation and getting worse. Better look at your road gear, you need to have more than a few flares and a bottle of water because things could go crazy at a moment's notice.