For Russia, matters in Ukraine are close to an existential crisis, as Ukraine is intimately tied up with Russia’s sense of itself as presiding over a mini-empire of sorts. Nor could an autocratic Russia tolerate a free and prosperous Ukraine, developing along the lines of Poland. America cares about Ukraine less, and cares more about Syria and Iran, or at least cares about saving face in those latter venues. Therefore there is a Coasean deal to be had between America and Russia, where Russia gets to partition part of Ukraine, create a buffer against Europeanization and democratization, keep the larger Ukraine unit weak, and also keep its Black Sea fleet. In turn Russia would do something less than totally sabotage all American plans for Syria and Iran. (Of course that is Coasean for the leaders, and not necessarily for the citizenries.)
The thing is…China. What kind of signal would such a Coasean deal of partition send to China?
That is what I worry about.