Drunk with it's victory over the collapsed USSR, Washington decides "why be friends with Russia when we can just run it into the ground and have it all?" NATO, which is Washington's tool to extend its power to Europe, instead of winding down undergoes 5 waves of extension to the east, moving all this military infrastructure closer and closer to the Russian borders. Russia objects all the way through, of course, but it is in shambles to be taken seriously. Then there is a coup in Ukraine in 2014, aided or maybe just fully orchestrated by the Washington and others, ppl that come into power are pro everything Europe/US and against everything Soviet (hence nazi marches in Ukraine now), and they want very much to join NATO too. So Russia does what it does, most notably the annexation of Crimea (after a referendum there btw). That, plus LNR and DNR that secede, and Ukraine becomes a little bit of a poisoned fruit at least in terms of being able to join the NATO legally (since they now have disputed territories). So Ukraine here is just small change. The conflict is really about Washington extending it's sphere of influence and it's weapons closer and closer to Russia, and Russia, finally, having enough military strength to do something about it. In short, it's about money and power, and who in this world is the hungriest hungriest hippo when it comes to that?