Although I can see the average Russian being nostalgic for the former USSR and wanting a strong Russia, I really can't see wanting to send your only son to die for it.
Now look at history. I know it's no longer fashionable to have any kind of memory in the west, but Russia undoubtedly remembers the massive sacrifice it paid to win WWII and the scourge of fascism, so the combination of Nato expansion and a blind-eye given to the nazi segments in Ukraine and bombings of Donbas is an impetus to act.
Ukraine isn't a democracy and we shouldn't be pumping money into a corrupt regime.