russian people think they are above other nations, specifically slavic nations.
russians are fascists. even educated and literate, "liberal" people of them are such.
With Kyiv under control, they can claim history and culture of Rus (also known as Kyivan Rus').
This is the fundamental ideological reason for the war going on since 1657.
Russia is the largest country on earth (twice size of US) yet it has half the US population.
The US has two neighboring states and two oceans that border it (with strongest navy in the world). Russia has 14 neighboring states and several neighbor areas in frozen conflict. Russia has no oceans separating its adversaries.
In terms of history, Ukraine (and Belarus) have been the routes of choice for military invasions into Moscow.
As a result of this security situation, Russia (and the Soviet Union before it, and the Tsarists before them, ...) relies on having a neutral periphery as a buffer zone. Ukraine declared itself neutral in its constitution at the formation of the country as it split from the Soviet Union. In 2019 Ukraine stripped neutrality from its constitution and wrote in pursuit of NATO membership.
For Europe not knowing where it ends, just look at EU membership, potential membership, and statements evolving over the past several decades from officials about where Europe ends.
The proximal cause of the war, literally the day-by-day timeline leading up to the conflict, was the Biden Administration threatening to pull Ukraine in NATO, Russia stated this was a red line and that it would invade and destroy Ukraine rather than let that happen, and then Russia and NATO diplomacy failed to resolve the issue.
This is clearly what the war is about: it is what led day by day up to the conflict, Ukraine's president offered to withdraw NATO ambitions as the invasion began to passify it, the Istanbul Peace Agreements early in the war centered on resolving the topic, and the peace discussions now have centered on it.
other options after ru invasion in 2014?
oh, georgia also wanted to nato in 2008?
oh, so because of this ru pumped up mil and 2use tech production since 2001?
is not ru country (no ussr nor ru empire), that current ru, promised do not do all of above on paper signed?
This happened in 2014. Also, if you remember, before starting the war Putin demanded that NATO stops expanding to the East, but was ignored [1].
So basically Russia wasn't willing to lose a large neighbouring country to US.
[1] https://en.wikipedia.org/wiki/December_2021_Russian_ultimatu...
so russia not willing to loose sovereign independent country to which it promised to secure it to be so? how one can loose what he does not have nor owns?