After the fall of the USSR, the Ukrainians had the opportunity to compare how things worked in the EU versus how they worked in Russia. As a result, they wanted to be more like the EU and less like Russia.
Meanwhile, Putin and a large enough slice of Russia remained unreconciled to the collapse of the USSR. They pined for the old days when the Warsaw Pact and Soviet communism empowered Russian imperialism.
As best as I can tell, Putin and his allies want a modern form of tsarism and the traditional Russian policy of imperial domination of its neighbors, with Ukraine being the key piece that would enable decisive power moves against Europe.
For a time, Putinism worked, backed as it was by Russian oil and gas and other resource wealth, founded on one-man rule, corruption and gangsterism coordinated by the security services, and enjoying the feebleness and acquiescence of the US and NATO toward years of Russian bad behavior.
Yet every policy and strategy -- even the most successful -- have their limits, just as every gambler eventually goes broke if they do not know when to quit. And Putin seems to have lacked the innate sense and good advice needed to see that Ukraine was too large a prize to be taken by Russia -- and especially not by Russia's incompetent military.
My brother and I go back and forth over US support for Ukraine. Against his "Don't poke the bear" line, my response is that I do not want to poke the bear, I want to kill it. It has gone rabid and has been eating its neighbors. Now that the bear is in a trap, this is our chance to kill it before it starts after our friends in NATO.
My plan for peace is simple: victory, meaning Putin dead and Russia broken.
Is it worth Nuke War? Is it worth five American Cities? or ten? Let me know. USSR is no more. How many American Death will be worth getting Russia to change leaders? 20 Million? maybe 40 Million. Maybe 100 Million? Before Russia falls you can bet that Kiev will be the first to be turned into a big glowing hole in the ground.
I think it's worse than that. "Committed" implies making a choice. IMO Rusia's form of imperialism is, to quote a Klingon Captain in Star Trek TNG, "bred in the bone". Or (staying with Star Trek paraphrasals), it is far easier for a civilized man to behave like a barbarian, than for a barbarian to behave like a civilized man. The latter is not a choice, the "barbarian" simply has not evolved the capacity to think like a civilized man. Pooty and his crowd literally lack the ability* & experience to pursue a course other than imperial aggression to counter what they see as a socio-economic threat.
Putin could have chosen something more like the Chinese model of 1980 to approx. 2010, but hasn't. The model of, say, Poland, has been successful too, while remaining fairly socially conservative. Instead, Putin's Russia stays "old school Russia." And a lot of Russians are fine with that.
*"Bred in the bone"? Well, until a few days ago I'd have thought that did not actually mean a genetic disposition, but, have you seen the work being done that has found a "friendliness gene" in dogs, but it's not in other canines? But, that gene IS found in a genetic mutation discovered in "excessively friendly" humans!