It was a shove

Professor Mearsheimer had another speech, though just before the invasion, that also said, as he did in 2015, that the crisis was our fault.

Some claim we did not provoke the war.  In fact, there were 30, 80, or 105 years of provocations, depending on how counted, reaching a creshendo apparently with a huge increase in the artillery attacks on Donbass (it's hard to believe false-flag attacks so widespread, though westerners were primed to think such a thing), AND with Zelensky's threat to tear up the Budapest Agreement (many think he was prompted to say that).

It was a shove.  The neonazis in Ukraine were eager to end the stalemate.  And the leash was off, because with the Americans gone, this was the appointed opportunity.  Russia would then commit a war crime, sanctions rolled out, and the job done.  But contrary to years of assurances otherwise, and many "Realist" thinkers aptly arguing it was not in Russia's interest to do anything big, Putin made the big move.  I could only hope it quickly settled the situation, with all soon forgetting.  In this case, idealism is also the pursuit of endless war.

Ukraine is situated not unlike Texas in the USA.  It's as if Texas had been part of US (as Ukraine was to USSR and before) then became a separate state (as some have wanted for awhile).  Now imagine this separate country of Texas joins an alliance with Russia, and Russia and all it's partners start sending equipment and troops.

Now imagine it didn't just join this alliance with Russia with it's own mixed politics, it was neutral until Russia came and instigated a coup of white supremacist types from the south who engaged in street warfare in Austin, who set up a new government representing them and the outside power, causing opposite leaning regions to declare independence, with protection from the US, and a civil war ensued inside Texas with these regions who refuse to accept the coup being surrounded.

Now imagine this hypothetical Russia was not the 3rd rate power or whatever Russia is, but the world's only superpower for the last 80 years, with 80+ bases around the world, the richest country in the history of the world, with the richest and deepest alliances.

Now imagine this Texas with global enemy alliances representing the majority of wealth on earth decides to start making it's own nukes.