The Winter War, like Manchuria, was a "crime against peace" by the standard of Nuremberg; that establishes that Stalin, like both Hitler and Hirohito, had launched a small aggressive war prior to WWII.

The purges were not part of the war any more than the Holocaust was part of the war (pointed out at Adolf Eichmann's trial: the continued prosecution of the Holocaust actively impeded the Nazi war effort, especially by clogging up the railroad network); but I wanted to make it clear that Stalin as well as Hitler exterminated large numbers of his subjects during his "reign."