38 years ago, as a student, I spent a month in Minsk, capital of Belarus, then part of the USSR. I used to take great delight in tormenting my hosts by using pre-revolutionary language, always referring to Leningrad as St Petersburg, upon which I would be immediately corrected. This was the time that the dead hand of Brezhnev reigned supreme, only 6 years after the invasion of Czechoslovakia. At the time never in my wildest dreams did I imagine that in less than 20 years the USSR would cease to exist and that Leningrad would once again be renamed St Petersburg.
I think the best observation is that of Winston Churchill in 1939:
"I cannot forecast to you the action of Russia. It is a riddle, wrapped in a mystery, inside an enigma; but perhaps there is a key. That key is Russian national interest."