Thoughts on Ukraine
My comment at the beginning of the invasion was that, in order for the Russians to lose, their military would have to be substantially worse than believed, the Ukrainian military substantially better. At this point both conditions have been met. While Russia might still be able to win the military conflict, it looks to me as though their strategy now depends on besieging Ukrainian cities in order to threaten to starve the population in the hope that that will force the Ukrainian government to make substantial concessions.
If my interpretation of the situation is correct, Putin now knows that the invasion was a mistake. The problem is that saying so and withdrawing make him look very bad, possibly resulting in his fall from power. At the same time, if it becomes clear that Russia cannot win, that the most it can do is to destroy a lot more Ukrainian property and kill a lot more Ukrainians, Zelinsky will be reluctant to agree to any terms that make it look as though Russia had gained something by the invasion. That raises the question of whether there is any agreement that would let both sides claim to their own people to have won.
Hence my suggested terms, conditional on its being reasonably clear that Russia cannot win a military victory:
Both sides agree to referenda in the Crimea and the Donbass region, conducted by a neutral party. If a majority in the Crimea vote to join Russia, Ukraine — and, presumably, other countries supporting it — agree to accept Russian annexation of Crimea. If a majority in Donbass vote for independence, Ukraine agrees to accept it. If, on the other hand, a majority in either region votes to be part of Ukraine, Russia agrees to accept that.
When the agreement is made, Putin can claim that of course Russia will win both referenda, hence getting the result it wants. Zelinsky can claim that he is agreeing not because of the Russian military threat but because Ukraine believes in democracy. The actual referendum happens after the Russian military has withdrawn from Ukraine, so if things don't go the way Putin wants he can complain that the referendum wasn't done properly but stop short of repeating the failed invasion. In fact, I expect Russia will win in Crimea, thus actually getting something it wants — international recognition of its seizure.
What happens in Donbass partly depends on whether the referendum is for the whole province or only the parts that have been under Russian and secessionist control. That is a high stakes gamble for both sides. A referendum in the whole province might result in Ukraine losing territory it has been controlling — but also might result in Russia losing territory it has been controlling, since the rest of the province may not be enthusiastically pro-Russian, especially after being invaded. Whichever way the referendum goes happens after the Russian army has left Ukraine, unlikely to return any time soon.
Two further points on the general issue.
1. I think the Ukrainian charges of genocide are pretty clearly wrong. The Russian military is obviously willing to kill Ukrainian civilians but if killing as many Ukrainian civilians as possible were its objective I expect a lot more would be dead by now. As I interpret their strategy, what they want are not corpses but hostages, people in cities whom they can threaten to starve if Ukraine does not agree to their terms. That doesn't work if the people are already dead.
2. I cannot make sense of Biden's claim that we cannot deliver Polish fighter jets to Ukraine because that would be a dangerous escalation. It would be an escalation if fighter jets piloted by NATO pilots entered the war. It would be an escalation if Ukrainian jets were engaged in military operations from NATO bases. But fighter jets are military equipment and we have been delivering military equipment to Ukraine throughout the war. If we turn a fighter jet, possibly unarmed (no missiles attached), over to a Ukrainian pilot at a U.S. air base and he flies it to a Ukrainian air base, how is that any different from our sending a truck full of anti-tank missiles or Turkish drones across the Polish border? How is it different if an American pilot, or perhaps a Polish pilot, with strict orders not to engage Russian targets, flies it to a Ukrainian air base to turn over to a Ukrainian pilot?