If the Russians can conquer Ukraine because they think it isnt a real country, a

If the Russians can conquer Ukraine because they think it isnt a real country, and really russia hasnt much claim to being a real country, then why dont we just conquer Russia? I mean, the chinese are winning in the east, the muslims in the south – so why dont we just take the west and russias resources, burn all their records and books and divide management if the territory to the eastern europeans?