What would the world look like without Hitler? Fiction is generally unequivocal about this: the removal of Hitler makes no difference, the world will still lurch towards a world war through some other path. WWII and the Holocaust are such major, defining events of the twentieth century, that we twist counterfactual events to ensure they still happen.

Against this, some have made the argument that Hitler was essentially sole responsible for WWII and especially for the Holocaust - no Hitler, no war, no extermination camps. The no Holocaust argument is quite solid: the extermination system was expensive, militarily counter-productive, and could only have happened given a leader lacking checks and balance and with an idée fixe that overrode everything else (general European antisemitism allowed the Holocaust, but didn't cause it). The no WWII argument points out that Hitler was both irrational and lucky: he often took great risks, on flimsy evidence, and got away with them. Certainly his decisions in the later, post-Barbarossa period of his reign belie political, military or organisational genius. And it was the height of stupidity to have gone to war, for a half of Poland, with simultaneously the world's greatest empire and what appeared to be the overwhelmingly strong French army. Yes Gamelin, the French commander in chief, did behave like a concussed duckling, and the German army outfought the French - but no-one could have predicted this, and no-one sensible would have counted on it, and hence they wouldn't have risked the war. Hitler wan't sensible, and lucked out.

Lay aside whether that argument is true, and let's explore its consequences. The counterfactual history is fascinating enough on its own - no rise of the USA and USSR as military superpowers, no Manhattan project, most likely no war between Japan and any western powers in the Pacific, the continuing occupation of China, and probably a much slower and Japan-influenced decolonisation process. Speculation and more sensible models do point towards another war: most of Europe allied against the USSR, a war that the USSR would most likely have lost.

That is all entertaining; but much more important is the fact that if WWII was an unlikely event, then the lessons we've learnt from it have been over-learnt. WWII proved that a developed, modern nation, could instigate genocide against segments of its population - but this doesn't mean that it's particularly likely. Similarly, appeasement backed up with implicit and then explicit threats failed to contain the irrational Hitler - but that doesn't mean they wouldn't have worked with slightly more rational leaders. Through aggressiveness and focus Hitler did conquer much territory - but the Nazi state was a crumbling morass of conflicting groups that would not have survived their leader. And in a counterfactual world without Hitler, with a contained or defeated USSR and an occupied China, there would not have been the rise of the great ideologies that shaped conflict in the 20th century. There would have been no European Union or UN. And how nuclear weapons would have been developed and spread is a great unknown.

So, if instead of seeing WWII and the Holocaust as inevitable, we see Hitler as singularly responsible, where would that leave us? More confident in the niceness of developed nations. More confident in the use of negotiations. Less likely to see dictatorships as effective governments. Less likely to see secular ideology as an intrinsically powerful force. Less likely to believe that supra-national organisations are easy to put together. And less likely to see nuclear weapons as intrinsically stabilising influences.