We've got a document that lays out the timeline in some detail, but I can't find it right now.

The short version is that this is a continuation of a very, very long conflict between the western powers and Russia for control of Russia's resources. Like in a broad sense this geopolitical conflict as been going on for hundreds of years - Europe and now the USA want access to Russia's resources and to do that they have to get rid of the government currently in charge of Russia. In the past this was all kinds of great power bullshit, Napoleon's attempt to invade Moscow. Then it was the Russian civil war, where all the Western powers invaded Russia to try to stop the Reds, then WWII when the Nazis and their allies wanted to conquer everything east of them, exterminate or enslave the Slavs, and do Westward Expansion 2.0: Eastward Edition. Then the Cold War, where NATO was formed to counter and eventually destroy the Eastern Block. Well, 1991 happened, the USSR was destroyed, A few coups and murders and the shock doctrine ensured that the capitalists could loot everything, but ultimately the West didn't get the complete control of Russian territory and resources they wanted. Too many former Soviet Oligarchs and gangsters got in the way and control of the region stayed more or less in local hands - Russian Oligarchs in Russia, Ukrainian Oligarchs in Ukraine, and so on. NATO didn't disband after 1991, and didn't let Russia join when Putin tried a few times,because NATO's purpose is conquest of Russia and they hadn't pulled that off yet. NATO started annexing countries and moving it's borders towards Russia, forward positioning troops and weapons, and gradually encircling Russia on it's populous Western borders. When NATO started talking about moving in to Georgia the Russian's responded, invaded Georgia, and put an end to that. At some point later NATO decided to move on Ukraine, take control, and use it as a proxy to weaken Russia. They used the same tactic by supporting the Islamists in Afghanistan decades prior, and they'd used it in the middle east and few other places. The basic program is - destabilize a country, flood it with weapons, then let their neighbors bleed themselves dry trying to contain the insurgency. In pursuit of this NATO deployed a bunch of Ukrainian Nazis they'd saved after WWII for exactly this purpose and were gradually able to expand their influence in the country. 2013, the President of Ukraine doesn't want to sign a shitty deal with Europe both because it would fuck over Ukraine and it would fuck over Ukraine's trade with Russia, and the Nazis, almost entirely headquartered in Western Ukraine, use this as an excuse to take control of popular unrest and stage a coup. It gets nasty, Ukrainian Nationalists burn a bunch of Russian speaking Ukrainians to death, they throw the president out, the new coup government immediately passes laws making the previously legal Russian language illegal. Out East in the regions where most Ukrainians speak Russian, they see a bunch of Nazis who want them exterminated couping the government, they see the new coup government passing laws against their language, they say "Fuck this, we know what comes next" and take up arms demanding that Kiev grant them autonomy - some government autonomy, guarantees on their right to speak their language and protect their culture, basic shit. Kiev says no, tries to send the army in to Donbass to crush them, the army tells Kiev "Fuck you". Kiev isn't giving up so they arm all the Nazis and send them in to Donbass and they start murdering people. This turns in to a civil war. During the civil war NATO moves in. They start re-structuring, training, and arming the Ukrainian military loyal to Kiev. They stockpile all kinds of weapons and shit. The Nazis are rotating back from the front lines with combat experience and are getting integrated in to army units while their civilian Nazi counterparts are getting more and more control over western Ukraine's government, civic institutions, and culture. This goes on for years, Ukrainians kill thousands of Ukrainians. Meanwhile Russia, who doesn't want any of this shit happening in their neighborhood, is trying to get some kind of peace negotiations going to stop the conflict and stabilize Ukraine before it falls apart and turns in to a failed state. Well, Ukraine and a bunch of NATO goverments say yes, we'll talk, lets resolve this, then the Ukrainian Nazis break all the ceasefires and shitcan the peace talks. Happens twice, the accords were called Minsk I and Minsk II. We later find out that Germany and France, who were acting as restaurants of the peace talks, never had any intention of fulfilling the peace conditions and were just buying time to arm Ukraine. Eventually it's 2020 or something. Ukrainians are sick of this, they don't want to be at war with their own countrymen, they don't want to get dragged in to war with Russia because of Nazi psychos, so they vote for Zelensky. Zelensky's a very charismatic guy, well known from television, speaks Ukrainian and Russia. He runs on a peace platform, says he's going to uphold the cease fire and start negotiations. Well, once he takes office he goes out to the front and tells the guys at the front to shot shelling Donbass. The guys who are running the Front are Nazi fanatics, they tell him he's not in charge and he can go fuck himself and they keep shelling. So now Zelensky knows how Ukraine really works, he starts working with NATO and the Nationalists as basically a cheer-leader for Kiev and Galacia's agenda. Doesn't really have any power but he looks good on TV. This whole thing finally comes to a head when someone decides that the Ukrainian army, with all it's NATO training and equipment and guns and NATO provided Nazis, is ready to go crush Donbass. There's a big build-up - Ukraine is mobilizing it's army to go in to the east of the country and fight the Donbass republics plus whatever Specops guys Russia has sent in there. Russia is mobilizing part of it's army at the Ukrainian border and making threatening noises.

Now, it's February of 2022. Russia has it's troops on Ukraine's border. Ukrainian troops are moving East in to Donbass. Putin is making threatening noises, but no one thinks he'll actually pull the trigger and cross the border. Well, for whatever reason, and it's still unclear what he was thinking, he pulls the trigger. He claims that he's doing it to protect Russian speaking Ukrainians from the Banderite Nazis who intend to genocide them (probably in the driving them from their homes sense rather than the extermination of all men, women, and children sense but who knows with Nazis?). That might even be true. But other reasons are that he was finally sick of putting up with NATOs bullshit after decades of post-cold-war hostility, or he had a bad understanding of the situation and thought he could win a decisive victory with that swift attack on Kiev, or maybe he thought people in Ukraine were more angry with their government than they were and would demand some kind of end of hostilities? Who knows, high level commanders and presidents aren't always very bright and aren't always getting good intel. Whatever happened, Russia made us all look like idiots by invading (pretty much no one, including me, thought he'd actually do it), and now there was a hot war between NATO forces and Russian forces, except everyone inside NATO pretends that it's between Ukraine and Russia.

So, that's the very, very, very short, basically no details, rough sketch version of what lead up to the war. I didn't even mention stuff like the activities of Ukrainian Nazis in Canada and the US, or all of Russia's security concerns, or the weird fucked up relationship between the Russiand government and the US government, or how Russia didn't really invade Crimea because the entire Russian Black Sea Fleet and tons of support personnel were already stationed in Crimea so they really just changed the flags, or the role of propaganda in NATOs decisions on which weapons to send and which weapons to withhold, or what Trump's trade war bullshit likely had to do with all this, or a trillion other things.

Suffice to say, there's a lot of history behind this conflict. And since it's very unlikely either side will definitively win there will probably be more wars in this on-going geopolitical struggle between whoever is in charge of the west and whoever is in charge of Russia in the future, even if NATO and the Russian federation both collapse tomorrow. There's no way we're going to make it through the 21st century without intense wars over the vast unexploited resources of Siberia.

Either way, that's the very short summary.

In 2014, the Ukrainian government was overthrown and the new government shifted towards Western alignment while banning opposition parties. Many people in Ukraine, especially in the east, have cultural ties to Russia and disagreed with the change, but were left with no means of having their voices heard because they were cut out of the democratic process, and that's why the resistance groups exist in the first place.