Because Ukraine is turning westwards. NATO is a small part of this, and largely irrelevant; it’s not as if Putin’s attitude to Ukraine has changed as it has become more likely to join NATO, or as if in the short or medium term it has ever been at all likely that Ukraine will actually do so.
Ukraine sees the healthy democracies and economic growth of other Eastern European countries, and wants to be one of them. This desire has been increased by the failure of the Russian economy over the past ten or so years; since 2013, Russian GDP has decreased by a third (or flatlined at PPP). The GDPs of Eastern European EU member states have continued to increase. Ukraine’s has continued to stagnate.
Even if denied membership of NATO, the EU, and every other supranational political organisation, in perpetuity, Ukrainians will still want to escape Russia’s orbit, and as long as Ukraine is a democracy (even if a seriously flawed one), they will try to do so. And as the gap between the Ukrainian economy and those of other Eastern European countries increases, they will try harder.
Putin doesn’t have a way to change this short of having Ukraine run by a dictator dependent on him for survival. Putin can’t increase Russian economic power, because he runs a mafia regime where his associates control and mismanage everything, and the only way to improve the economy would be to get rid of him. Not to mention the impact of the pre-existing sanctions, which again can only be removed by getting rid of him. He can’t increase the attractiveness of the Russian state and political model, because he’s a mass murderer who runs a mafia regime, and the Russian state and political model can only be made more attractive by getting rid of him.
And all European countries are trying to stop using fossil fuels by 2050. And seem to be serious about doing so. Which means that in any realistic forecast, a Putin-controlled Russian economy is going to do increasingly badly over the next three decades.
The war would not have happened if Putin had not given the order for it to happen, and if someone else was in Putin’s position then it seems unlikely that it would be happening. No one knows what’s going on Putin’s mind, and so no one can be sure why the war is happening. Maybe he’s become obsessed with Russian greatness and expansion, maybe he fears Russian decline will lead to his overthrow, maybe he’s hooked on meth and in a state of paranoid psychosis, maybe he’s obsessed with Ukraine in particular becoming part of Russia, maybe he fears the collapse of the Russian Federation if its non-Russian inhabitants see a dependent country leave the Russian orbit and succeed, maybe he fears the collapse of his regime if Russians see a democratic Ukraine succeed, maybe he thinks that he’s the reincarnation of Peter the Great, maybe he believes that Russians in Ukraine need his protection, maybe he thinks that Russians everywhere in the old Eastern bloc need his protection, maybe he believes that Ukraine’s leaders are puppets of an American government determined to overthrow him and/or undermine Russia, maybe he thought the Ukrainian army was getting stronger and so he had to act now, and probably some part of most of the above (maybe not the meth one) and several others. The common denominator in all of these theories (maybe not the meth one) is that it is the combination of these beliefs of Putin, which are currently unknowable, with the Ukrainian move westwards, that has meant that the war is happening.
Samo Burja has referred to Russia under Putin as a live player; a country able to do things it has not done before. This is debatable given Russian history (he defends his argument on the basis that post-Soviet Russia is a new country). What is unarguable is that Ukraine is a live player, and, given the situation outlined above, would be likely to remain one even if Zelenskyy was no longer President (as long as he was replaced by another leader chosen by Ukrainians). It is doing things it has never done before. These Ukrainian actions have led to a situation where a mass-murdering scumbag has decided to declare war, for reasons that are currently unknowable. But they also offer the hope that Ukraine can be a free, prosperous, democratic state. Ukraine is not a pawn of Russia, the US, or anyone else. The most important decisions that led to this war were made by millions of Ukrainians, and one evil Russian.
I’d be very uneasy about any of the scholarship in a book that from your description (and I think at least one other review that I’ve read) just ignores reality on the Kandiaronk stuff, and some of the other things it discusses. If you know you can’t trust them on things they obviously get wrong, can you trust them on any of it? It seems much more likely that if you got experts to review the bits of the book relevant to their areas of expertise, the conclusion would be that a lot of it was worthless, actively misleading, or not even wrong.
Your description of the book makes me want to read it. It sounds fascinating, and stimulating. I just feel like I might learn more by reading a series of rebuttals of their arguments from people who know what they’re talking about.