Ukraine in both the EU and Free Association with Russia

Civilly, Russia would only at most be saying to the Ukraine: "You can't have me, 
if you're going to be in the EU." As the EU would at most only be saying, "you 
can't be in the EU, if you're going to be in Free Association with Russia.  Though 
it is highly unlikely, either has a problem, with the Ukraine being in or with the 
other.  It would not come to war.  NATO and the Donbas are issues of war.

If Cuba was letting Russians put their military in its country, it is probable the 
U.S. would be bombing Cuba.

Rather the fighting over the imposition of Ukrainian rule in the Donbas, the 
Donbas and the Ukraine should be in Free Association.