Russia had already attacked and invaded Ukraine in 2014. In 2022, it simply renewed its drive to take more Ukrainian territory. There was no imminent decision in 2022 for Ukraine to join NATO, nor was there any event pending that justified the invasion. There was an international outcry against the obvious preparations for a renewed invasion, but Putin turned a deaf ear to them.
NATO exists for one purpose--to oppose Russian expansionism into Europe. After the collapse of the Soviet Union, every single satellite nation in the former Warsaw Pact rushed to join NATO and strengthen ties to western European economies. Moreover, the formerly Soviet-occupied Baltic republics also rushed to join NATO. Ukraine, with its past history of Soviet atrocities committed by Stalin (
Holodomor,
Great Purge), also wanted to join NATO as insurance against Russian expansionism. It is true that many Ukrainians have strong family and cultural ties to Russia, but that doesn't mean that they wanted to become part of Russia. The eastern regions, along with the rest of Ukraine including Crimea, all voted for independence from the Russian dominated Soviet Union. Russia had signed an agreement to respect Ukraine's sovereignty with the
1994 Budapest Memorandum, and we've seen how well that worked out. At present, there is no agreement that Ukraine can come to with Russia that can serve to protect it from more invasions by Russia in the future. Therefore, its demands to join NATO have been entirely understandable and reasonable. The only possible diplomatic solution to the current war must be with Ukraine joining NATO. NATO did not expand into Eastern European nations. Eastern European nations expanded into NATO.
Vladimir Putin is purely and simply a fascist dictator with an ethnocentric view of nationhood that bears many similarities to Adolph Hitler's Nazism. His insistence on occupying Ukraine relies on the same kind of logic that drove the
Anschluss with Austria and the annexation of the Sudetenland in Czechoslovakia. He also uses the ethnic Russian populations in the Baltic countries as an excuse for meddling in their internal affairs, although their membership in NATO protects them from a Ukraine-style invasion. Belarus is already pretty much a vassal state of the Russian Federation. Putin's "
United Russia" (
Yedinaya Rossiya) party isn't yet as brutal as the Nazi Party became in Germany, but its basic philosophy is to promote ethnic Russian dominance over other regional ethnic minorities both inside the Russian Federation and to promote the interests of what they call "ethnic Russians" in neighboring countries, based on their dominant language. It doesn't matter whether the so-called "ethnic Russians" in those countries want to be assimilated. They are assumed to want it.