It’s a bit of a side point, but Britain and France stupidly drove the USSR into a pact with Germany.
The Soviets should have been invited to the 1938 Munich conference. After all, the Sudetenland was much closer to the USSR than it was to Britain or France. Yet Stalin was snubbed.
So Stalin figured that if he didn’t ally with Hitler, he might be next. Germany would invade the USSR, and the western allies would do nothing. That turned out to be faulty reasoning. But it made good sense at the time.
You blame Putin for that?