>Kievan Rus' (Old East Slavic: Роусь, romanized: Rusĭ, or роусьскаѧ землѧ romanized: rusĭskaę zemlę, "Rus' land") or Kyivan Rus',[2][3] was a loose federation of East Slavic and Finno-Ugric peoples in Eastern and Northern Europe from the late 9th to the mid-13th century,[4][5] under the reign of the Rurik dynasty, founded by the Varangian prince Rurik.[5] The modern nations of Belarus, Russia, and Ukraine all claim Kievan Rus' as their cultural ancestors
Copied from the Wikipedia, so if anything that suggests we need to bring back the USSR and reunite all the Slavs under one flag.
роусьскаѧ землѧ literally translates to "Russian land"
> if anything that suggests we need to bring back the USSR and reunite all the Slavs under one flag
Okay, taking that at face value, nothing says Moscow has to be in charge. And the Mongols once controlled Russian territory. Speaking of which, Moscow hasn't controlled its eastern territories for long--should we dissolve Russian influence east of the Urals?
Returning "historical" lands is the casus belli of every dictator. It's arbitrary, empty and infinitely extensible.
On that basis NATO could legitimately support a military intervention by Kiev into Moscow. It was originally the Kievan Rus, after all.