Ahem... make your homework better next time. Ukraine is but a cannon fodder which its nationalists & compradors merrily ruminate. The war had started as civil, and only later conflict spilled over, under Russian irredentists' influence, albeit much catalyzed by incredibly stupid Russophobic policy of Ukrainian nationalists.
Then again, today it’s already irrelevant who ignited ‘the force of angry Heaven’s flame,’ atrocity respawns atrocity, blood calls for blood. We have there a total recall of Balkan wars, complicated by aggression of nuclear power, whose territorial interests were indeed brushed, in a brusque manner, by Washington imbeciles and their vassals in Kiev. Aggression it is, quite true, but not in a cold day in Hell was it unprovoked.