Just thought of this idea, what if.........
1933
-FDR is assassinated.
1940
-The US continues selling oil to Japan not minding it's invasion of china or other asian countries (due to isolationist taking control and not wanting to start a war with japan).
1945
-the USSR detonates an atomic bomb over Berlin and now rules europe.
1947
-The US, Japan, & Russia are now engaged in a 3 sided cold war.