Courage

 I've been away at a wrestling tournament, but I always had half an eye on the developments in Ukraine, obviously. It seems clear that Ukrainians, led at least in moral courage by their president, have put up a tremendous fight. I would not expect that to slacken.

Putin may very well have anticipated that Ukrainians would not fight to the death to preserve their national autonomy. That could be a case of the sort of epistemological closure that we see in authoritarian regimes (or the second Bush Administration). Maybe he really thought that Ukrainians wouldn't put up a fight, but their courage is proving legendary. From Snake Island to the Sunflower Lady, Ukrainians have shown a poetic fierceness in opposing this invasion. As military aid, including from Germany, starts to flow to Ukraine - openly, with no pretense or plausible deniability from NATO - and the Russian advance stalls, the worse things get for Russia.

There are two outcomes, if this continues to drag out: defeat of Russia or devastation of Ukraine. Putin has presented himself - at least to other Russians - as a liberator of Ukraine. So there has been a certain restraint to Russia's invasion. They have not bombed residential neighborhoods indiscriminately. They haven't engaged in "total war" tactics designed to destroy a county's ability to fight. 

They could, if things start to go even worse. 

Alternatively, Russia's will to fight against their cousins could erode in the face of stiff opposition. Watch for any signs of Russian units surrendering. The fact that large numbers of Russian troops - a largely conscript army that isn't especially well trained - have been held back, while more elite units go in, could suggest that Russian leaders worry about the reliability of their second tier troops to wage war on their neighbors. If we see a few mass surrenders, where company sized units essentially desert, that could be the tipping moment of the war.

With countries like Kazakhstan and China refusing to go along with this and EU countries slowly moving to ban Russia from SWIFT, this could be a regime change moment.  Just not in Ukraine.