If enlightened politicians and statesmen arose in the aftermath of the war, however it ended, a proto EU would form, with Germany presiding, by the end of the 1920s. If many of the participants remained insular and bitter, WW2 would not have occurred but many insurrections and revolts, most ethnic or nationalistic in nature, would occur beginning toward the end of the 1920s and continuing into the 1950s. All of the European powers containing minority ethnicities would spend huge amounts of blood and treasure combating these uprisings. The ultimate outcome of this would leave Europe having many small countries, think Holland in size and population, unless totalitarian fronts countered this fragmenting with far right ideologies forcibly gluing together disparate groups of people into larger nations.