Another week of Russia’s invasion of Ukraine has gone by, and Moscow has crossed yet another line with its aggression against Western targets. This time, the violation came in the form of a parcel bomb in the hold of a German aircraft. The device exploded on the ground at
Putin has surrounded himself with those who agree with him, and killed those who disagree who are at all in danger of getting a position of power. Unless you kill nearly everybody in politics nothing will change. (if you do I don't know what the result will be other than really bad - and no guarantee of change for the better even with just the Ukraine issue)
You're right there is a list, and they don't agree who should be in charge. Which means the internal problems would be a lot more important than the external war. Especially if there is a risk one of them might take western help to get in charge.
By the time they're ready to think about Ukraine again, there would be half of NATO sitting there waiting for them.
Did killing Cesar at the end of Fallout New Vegas teach us nothing?
The war machine is too far along to be stopped easily.
Or if WW1 is your poison:
Initially, Wilhelm II wanted to halt the German mobilization, hoping for a peaceful resolution. However, Moltke insisted it was too late to stop the complex mobilization process once it had been set in motion. He argued that it was "like a wound-up clock" that couldn't simply be unwound. His words essentially conveyed that the mobilization machinery, once started, would continue inexorably towards war, effectively removing any possibility of reversal.