Since Putin is apparently now a crazy old man with a Napoleon complex, this horrifying thought occurred to me: If Ukraine resists for many weeks, why wouldn't Putin use a nuclear weapon against them? It'd be like the situation with Japan and the US in WWII: Putin can nuke a couple of Ukrainian cities (probably in the western half) and say, "Surrender unconditionally or I'll nuke a couple more." And he could just continue nuking cities until Ukraine capitulated. NATO wouldn't respond with direct military action, Ukraine doesn't have nuclear weapons of its own, and sanctions are already nearly maxed out. I don't see how Putin has much to lose with this strategy (except that it might horrify his direct subordinates or population enough for them to oust him), and it's a sure-fire way to win Ukraine.
You might think that Putin wouldn't want to get a radioactive wasteland as a prize, but that'd be a misunderstanding of the effects of nuclear weapons. Using appropriately-sized nukes, Putin could destroy dozens of cities without making Ukraine generally uninhabitable. The radioactive fallout would cause serious issues (worse in Ukraine and extending worldwide), but it wouldn't kill that many people in most areas, and it would decay in weeks.
To try to prevent this, the West urgently needs to find some way of giving Putin some sort of hope that he personally can improve his situation without conquering Ukraine. As things stand now, there seems to be zero hope of the sanctions ever being lifted as long as Putin is alive, so Putin sees that his only two options are to give up and become an iron-fisted dictator of a poor country, like North Korea, or continue pursuing his dream of restoring the Russian empire at all costs. The West might offer Russia a series of steps that would lead to progressively removing the sanctions, and it might even be worth offering Putin safe personal exile (like Napoleon) so he can retire in peace. He probably wouldn't take a quiet retirement, but it doesn't hurt to offer it.
If you're within about 150 miles of Ukraine, it'd be a good idea to:
- Put important files onto optical media, since a nuclear EMP may destroy hard drives and SSDs.
- Buy potassium iodide tablets. In case of nuclear fallout, adults take 130mg/day. This will help your long-term survival, but will absolutely not make you immune to radiation.
- If possible, prepare 2 weeks of food and water in case you have to shelter from fallout. An appropriate shelter will put as much matter between you and the outside world as possible, without any direct airflow. Air filtration isn't necessary, but air should not be able to flow freely in from the outside. Fallout will especially accumulate on the ground outside and on roofs, so you want your shelter to be far from those. A basement is good if it's deep enough, but a shallow basement isn't ideal because you're too close to the ground outside. A subway would probably have too much air flowing from outside. The middle floors of a very tall building can be used, staying as far as possible from the exterior walls.
I hope that the Ukrainian government has made some preparations for dealing with nuclear fallout.