What if the takeover of Germany by the Nazis or a similar ultranationalist group is prevented, and whatever regime does end up replacing the Weimar government does not have expansionist ambitions beyond perhaps Austria and does not seek a war with the western allies? Could a second world war still happen, but with the Soviets instigating? Might Stalin (or a different soviet leader, if you think his ambitions aren't compatible with a European war) have instigated a war in Europe that draws Russia into a confrontation with the Western Allies? What allies would the Soviets have, if any? Would East Asia be involved in such a war?