This Twitter thread makes a convincing case that Russia will invade Ukraine
https://twitter.com/DAlperovitch/status/1473362460673515527
If it happens, every single country in the world should mobilize its military forces to defend the side that is attacked. That was the raison d'etre of the UN: collective security. They should then use sanctions to punish the attacking country as a deterrent and method of accountability. Unfortunately the UN is a broken piece of crap because Russia and the other UNSC permanent members have a veto, among other reasons. This isn't the US's fight if it happens, this is the world's fight vs unlawful aggression of a country's basic sovereignty.
This reminds me very much of the run-up to the Iraq invasion by the US and UK etc. Except Russia and China have desire to annex territory they see as historic parts of their "empire", no different than Nazi Germany.