No Winter War: Stalin turns against Turkey in 1940 instead.
Looked up if there had been made any threads about such a possibility, seems not to be so.
Rather than demand seccession of Finnish territory, Stalin settles for demanding passage of food, fuel and ammunition supplies through Finland to Leningrad instead.
This proposition is accepted by the Finnish governement.
Stalin instead, have decided to move much further south. He want to expand the Georgian and Armenian SSRs and obtain an opening to the Mediterranean sea.
So Stalin thinks, when Germany have defeated the colonial powers, there will be a buffer for the caucasian oilfields and Iran would be under direct soviet threat and unlikely to side with the axis.
Possibly, he makes an alliance of convenience with either Bulgaria or Greece, perhapse both. In exchange for taking care of Istanbule, Stalin´s allies receives Red Army equippement.
Date of attack, either April 1940 or August 1940 (assuming Case Red happens as IOTL and Stalin decide to move against the Turks 2 months after the French armistice and BoB in full swing).
What would be the effects on WW2?
Alternatively, without a winter war, would Hitler abandonne the idea of a Norway campaign and instead settle for advancing the date of Case Red before the allies eventually invades Norway?
If there is no Norway campaign, does Churchill still rise to power or does the German victory against France result in the rise of Halifax instead?