Kyivan/Kievan 'Rus was not a, "Ukrainian," civ, but an, "Old East Slavic," civ. There were no separate Russians, Ukrainians, Belarusians, Ruthenians, Carpathians, Gallycians, Rusyns, or any other such thing back then, and one modern Belarussian and several modern Russian cities were part of the city-state-based structure. Saying the Kyivan/Kievan 'Rus was specifically a, "Ukrainian," civ, and not a general ancestral, "East Slavic," is about as revisionist as Putin saying, "Ukraine never existed." Both Russia or Ukraine - or the Soviet Union - should be able to easily transform from the Kyivan/Kievan 'Rus.