I was intrigued by the Idea of a WW2 fought between a Communist USA and the USSR on one side. And a group of Fascist states on the other. Anyway, I don't know much about the Interwar period. But I was thinking something like Poland is defeated in the Polish Soviet War. Which terrifies Britain and France. This leads to Germany being placed in the League of Nations early and gets a bit of the territory it lost to Poland back as a barrier against communism. The British, French and Germans all slide to the right. DNVP takes power in Germany in 1933 because it manages to do better due to making it seem like they are the reason they regained territory or something. France is the next to fall to Fascism and then Britain. The USA turns communist at some point, not sure when.
I'm sorry if this sounds muddled and dumb, it's 12 am and it sounds really good in my head, but I'm not sure if it's coming out right. But bascially Left vs Right for control of the world.