Putin takes Luhansk and Donestsk, consolidates the southern coast, and links to Transnistria. Ukraine is now a landlocked welfare case for Europe, with millions of refugees streaming out and a government in collapse. Just like that, Russia has a salient into Western europe, and the world order of national sovereignty comes to an end. There is no complexity to the issue. This is the clearest, most mortal threat to Western civilization since the collapse of the Soviet Union. Do not fall for "let's hear both sides" whataboutism.
It doesn't happen often, but sometimes in life there is simply right and wrong.