What if the War in 1939 started with the declaration of war by both UK and France against not only Germany, but also the USSR, for also invading Poland in september 1939?
Primary point of interest is that the anti Communist thinking still was widespread and the USSR had absolutely no sympathy in the non communistic world. Finland, already at war with the USSR was supported by the West, so why not going for an all out war entirely, since the Finnish People had shown the USSR to be pretty weak in military terms.
Things might even be more complicated when Germany also struck at the USSR in sumer 1941.