Soviet forces had been fighting Japan in 1939, which helps explain why Moscow did not move into Poland at exactly the same time as Germany. The Winter War had also demonstrated how costly Finnish resistance could be. In this counterfactual, those experiences make a fresh intervention in an armed Scandinavia unattractive. The Soviet Union was also politically aligned on the wrong side of the European war at this stage, complicating cooperation with the Allies.
Notable Point · 1:17:34-1:18:08
Why Moscow may initially stay out of Scandinavia
Recent fighting against Japan and Finland gives the Soviet Union reasons not to open another northern commitment immediately.