If the legal status of the soviet union wasn't a federal union, it's constituents could've not broke up by the end of the 80s. Legal status matters, even when

If the legal status of the soviet union wasn't a federal union, it's constituents could've not broke up by the end of the 80s. Legal status matters, even when it is a facade. Another example: even though power was very centralized in Mussolini's hands in Italy, Italy was still a monarchy and the king could depose Mussolini in 1943. Also, the fact that power was very centralized, does not change the fact that countries still operated autonomously and there's no reason to believe censuses would not be counted differently in the different republics.