It's official

[plloyd1010]

There was a little something going on in Asia well before 1939. If the war in Europe is delayed one can assume Pearl Harbor is also delayed or never happens, leaving the Japanese with literally no reason to declare on the Soviet Union.

I'm not so sure about either of those points forcing the European issue. Firstly the Japanese army was pretty well done messing with the Soviet Union. Even after the Nazi invasion of June 1941, the Japanese still were not into taking them on. Secondly even though Roosevelt & Churchill agreed Germany was the main threat, Roosevelt did not believe, even after Pearl Harbor, that he could get a declaration of war against the European Axis. He had to wait until December 11th for Hitler to declare war on the U.S.