It shouldn't be that hard for people who sympathized with Putin to turn around and sympathize with Ukraine now, and it can be done with complete intellectual consistency, but few seem to be managing it. It's like telling a woman that she shouldn't taunt her man, and then switching to her defense when he snaps and starts chasing her with an axe. Yes, you've been proven right, but it's no time for gleefully saying "I told you so". Some provocations should not be given, but some reactions are far more than the provocation deserves.
I wondered prior to the invasion whether Biden and co. were actually trying to get the Russians to invade. Not that I thought they were: incompetence was the default explanation. But for months prior to the invasion, they were confidently predicting it. That meant that even if the buildup was originally meant as a bluff, they could brag about having forced him to back down, humiliating him. It removed the propaganda incentive to back down. It would have been far better to say something like "This buildup of troops is extremely concerning, and makes us fear an invasion, even though it obviously isn't enough to conquer Ukraine". (The troop ratio at the start of the war was about one to one, and indeed knowledgeable observers were commenting that this was insufficient.)
Also, there's a subtle and widely unappreciated sort of dominance that a free-thinking society has over an unfree one. On the face of it the situation is the other way around, with the unfree society being able to lie with impunity to its own members while seducing the free society with clever lies. But in a free-thinking society the people who rise to the top of the media heap are those who make the most persuasive arguments, not those who best pander to the government. A few words from able persuaders often cut more deeply than mountains of rhetoric from the other side. And while most of the population of the unfree country can be kept completely in the dark, the leadership has to expose themselves to outside arguments, even just for the sake of countering them. Though they listen 95% of the time to their own propaganda, the other 5% has an outsize influence. So within Putin's inner circles, the weight of Western opinion is non-negligible: if even we think it's in his best interest to invade, that means something to them; and confidently predicting invasion means that we think it's in his best interest.
Also, the main threat the Biden crowd used -- the threat of sanctions -- isn't something that can be expected to deter someone like Putin: he'll think he can weather them. Even when sanctions truly will be crippling, he won't believe it until it actually happens. This is not just dictatorial wishful thinking and being surrounded by yes-men, though that's a lot of it. In a sense a head of state should be optimistic about things like that: he should think that some way out will be found: that some substitution can be made, even if it isn't clear ahead of time what that substitution might be. He doesn't know the details, but he knows the nation has a lot of clever people who will be trying their best to work around the difficulties.
In any case, talking only about sanctions was basically a promise not to fight. Yet it was combined with absolute intransigence in negotiations (at least in public). It showed no appreciation for Putin's circumstances: having made such demands, and having made such a large buildup of forces, he had to have something to show for it. It didn't have to be what he asked for, but it had to be something. The trick was to figure out what he could be given without losing anything essential. (At Munich, Britain and France gave away not just a slice of land but Czechoslovakia's border fortifications, essential to the defense of the country; German generals who later toured those fortifications were surprised by how formidable they were.)
Things that would have been reasonable to grant to Putin would have been acquiescence to his ownership of Crimea and acquiescence to his demand that Ukraine not join NATO. Now, we could (and should) have laughed at his demand that the exclusion from NATO be in perpetuity: there never have been any political agreements that lasted forever. But a ten-year exclusion could have been on the table. And besides, part of Putin's argument was that Russia had been promised no further extension of NATO -- and so now he wants more promises, from people who according to him have already broken their past promises? The demand was laughable, so we should have laughed at it: what the hell, we can grant that, but no silly language about perpetuity.
The Ukrainians might also have given the Russians some satisfaction on language laws. Prohibiting newspapers from being published in Russian unless they also put out a Ukrainian version is a law that ill-suits a country aspiring to freedom.
There's also been a sort of nagging, domineering spirit in the US, which tries to micromanage the rest of the world, largely through the financial system. The peak of this is perhaps the Magnitsky Act, passed by Congress at the behest of Bill Browder, who said that his lawyer Sergei Magnitsky was beaten to death in a Russian jail by eight people with rubber truncheons. How he could know such details (eight? rubber?) is a mystery. And then there's Browder's own shiftiness about the matter (running from process servers, and then when finally forced to make a deposition, admitting that Magnitsky had no law degree and was an accountant), and the fact that Browder himself renounced his US citizenship (likely for tax reasons), making the credulity with which Congress listened to him quite surprising. (They seem not to have even really considered the Russian government's side of the story.) All and all it does not seem right to take sides in such disputes; there is good reason for leaving foreign disputes to foreigners. At any rate, through the Magnitsky Act and other acts, we don't just sanction nations any more: we also sanction individuals. It's not a hugely effective way of proceeding: the sanctioned individuals can often get around them by putting their foreign transactions in someone else's name. And foreign governments rightly resent it: "who are you to judge our people for crimes committed on our land?"
As for Crimea, the Black Sea Fleet has been a big deal to the Russians for hundreds of years; probably the only way to pry Crimea from their hands would be a nuclear war. And Crimea was in their hands. Diplomatic fictions -- "not recognizing" this or that fact-on-the-ground -- are beloved of diplomats (all the work it takes to maintain them is job security), but it can be questioned whether any of them has ever really been worthwhile.
People spoke of such possible concessions as "Finlandizing" -- a word I hadn't heard for a while, and which reflects a shocking ignorance of the true state of Finland. Now, Finland lost territory to the Soviets in the Second World War, and as part of the peace treaties had to promise to not make anti-Soviet moves; they did not, for instance, join NATO. (The treaty expired, so their current joining of NATO is not in breach of it.) They also bought a lot of Soviet weapons.
But people who think buying Soviet weapons was an indication of subservience have something to learn about the Finns. Finnish logic was more like: during the last war, we killed hundreds of thousands of Russians and captured many tons of their weapons, which we then put to good use against them. We expect to do it again in the next war, and starting out already familiar with their weapons will help with the process. And besides, the weapons are reasonably cheap and effective, especially once our armorers have tuned them up a bit. Weapons purchases are just weapons purchases; they don't stop us from being a free country.
Now, the Finns didn't like promising not to make anti-Soviet moves. But it was a lot better than fighting a war -- and ultimately the country that collapsed was the USSR, not Finland.
But such possible concessions are "what might have been"; they are not applicable to the present state of affairs. Returning to the pre-war situation is as impossible as un-breaking an egg.
As things are, it is not out of the question that the Ukrainians might succeed so well as to drive the Russians out of the Donbas. The Ukrainians have officially mobilized -- that being military jargon for bringing the army up to wartime strength; their army will be growing by leaps and bounds. The Russians have not mobilized; indeed officially this is not a war to them and peacetime rules (such as soldiers being able to leave the army) still apply -- though unofficially, well, good luck trying. They have taken steps to recruit new soldiers, but only steps short of official "war". And they are busy feeding their existing soldiers into the meat grinder. Still, if the Ukrainians were to bring up fresh troops, make a counteroffensive, take the Donbas, then get giddy with success and try to invade Crimea, the Russians quite likely would nuke the invasion force.
Then serious negotiations could begin.