Until 2014, Ukraine was led by a puppet of Putin (Viktor Yanukovych ), who is said to be the main choice as leader if Donetsk is separated from Ukraine, which would perpetuate the Russian influence. The Ukrainians overthrew him in 2014 because of his stance on Russia taking Crimea.
HF, in the fog and emotion of war there is a surge of bad history out there. It's important to look at the timeline to interpret events. These are bullet points with much going on between the lines.
2010 - Yanukovych won an election 49% to 45%. There was controversy but ultimately the election was endorsed by PACE and OSCE the international agencies.
Nov 2013. Yanuk. made the decision to move away from an association agreement with the EU that had been in negotiations and instead chose to establish closer ties with the Russian Federation. Pro EU protests started and than things began to go out of control. Both Western and Russian outside influence were behind protests.
21 Feb. Yanuk signs a compromise deal with opposition leaders that promised constitutional changes to restore certain powers to Parliament and called for early elections to be held by December 2014.
The next day, 22 Feb UKr Parliament still votes to remove Yanuk from power.
2014 March. Putin invades Crimea. Remember Crimea houses the Russian Naval base of Sevastopol, which is important to Russia as San Diego is important to the US Navy. It is a very strategic port that the Greeks, Romans, Venetians, Genoa, on and on. have fought over for centuries and is the gateway to the Mediterranean Sea.
For any proper Western analyst, the Crimean move was entirely predictable at the time. Another failure by Leadership.