John Mearsheimer on why the West is principally responsible for the Ukrainian

The bigger question is how far Putin is willing to escalate it so he can pretend to claim victory, the West has zero agency in getting Putin to stop unless they are prepared to escalate themselves, but apparently we are willing to stand by watch thousands of people get murdered, using illegal weapons no less. Appeasing Putin is what got us into this war in the first place, it made the West look weak when in fact all they wanted was to avoid yet another war. But we're there now, and that changes everything, looking back at how you got here may help inform the worlds response to the next dictator that tries for a landgrab.

Mearsheimer may well have had a point, but it's easy to argue from the sidelines, the options before us at the time, to either allow Ukraine into NATO or to let them fend for themselves both had significant downsides. Dictators do what dictators do: throw people into the meatgrinder to make up for their own deficiencies, it doesn't need any high degree of intelligence to observe that, least of all about Russia.