'Let's Kill Hitler' is the title of a Doctor Who episode. It's also a topic that keeps cropping up on the internet. The idea that, if one has a time machine, the first thing to do is to pop back and liquidate the Nazi dictator has become conventional wisdom (if any notion that depends on time travel can be deemed wise). But would killing Hitler make any difference to history? And if so, would that difference be great or comparatively trivial?
Well, let's give it a try. We active our time machine and pop back to a time when killing Hitler is comparatively straightforward. How about sneakily administering a drug to Hitler's pregnant mother, so that she miscarries? A tad unethical? And - given the primitive nature of 19th century medicine - we would certainly endanger the life of an innocent woman.
Okay then, let's kill young Adolf as a child. Well, no, not a child. As a teenager. Yeah, what 15-year-old isn't obnoxious enough to merit strangulation? No, but seriously, we can't kill a little boy because, looked at from any moral angle that makes sense, if we do that makes us no better than the Hitler we've set out to kill. It's all very well saying that 'we're saving millions of lives', but of course we're choosing to take one undeniably innocent life right now (or then, anyway).
Well, all right then, let's find a set of circumstances in which killing Hitler wouldn't count for much, morally speaking. Fortunately, history has provided us with the ideal scenario in the Great War. Hitler was a front line soldier, he rose to the rank of corporal, he was gassed in 1918, and must have come close to death many times. All we need to do is get ourselves a British (or French) rifle of the period, pick our time, find the right spot, and blow Adolf's brains out. Problem solved.
Except that you have not altered by one jot the chain of events that lead to Germany's defeat, the imposition of the Versailles Treaty with its reparations, and the desire among many Germans - especially the officer class - to re-fight the Great War and get a 'correct' result. You have not stopped the German army in the Twenties from rebuilding itself, albeit covertly. You have not stopped them from testing their new artillery etc in the Soviet Union, away from prying British and French eyes. All of this happened quite independently of any Nazi ideology.
You may believe if you kill Hitler in 1916 (say) you will prevent the Holocaust because his race theory was a peculiarly personal thing. But Hitler's race theories and obsession with Jewish conspiracies were commonplace stuff. Anti-semitism was the common currency of the European right-wing thought in the Twenties and Thirties. Eugenics, racial purity, the idea of the Germans as a 'master race' were not Hitler's ideas. Houston Chamberlain, a British political writer, was one of the many intellectual fathers of Nazism.
German militarism was on the rise again, long before Hitler came to power. The German military elite had never accepted the Treaty of Versailles. They subscribed to the 'stab in the back' theory, that leftists - many of them Jews - had brought down Germany from the inside in 1918 by fomenting mutiny among the troops and dissent among civilians. The use of right-wing mercenaries - The Frei Korps - to massacre communists in the aftermath of the Great War was practically a dress rehearsal for the Nazi era. The same can be said for the assassination of the left-liberal Jewish statesman Walther Rathenau in 1922.
As for mass extermination of civilians, the Nazis were not unique in this, though they were the most efficient. The Armenian massacres in Turkey, Stalin's purges and contrived famines, Mussolini's invasion of Abyssinia, Franco's slaughter of his opponents, and the Japanese atrocities in China all show that such crimes were part of 'the spirit of the age'. World War 2 provided all the anti-democratic powers with a golden opportunity to carry out mass murder on a huge scale, not least because only by fighting a total war could they have mobilised sufficient personnel to kill millions by any means. War also hardens the general outlook of a people, and of course makes it even less likely that accurate information will get out concerning atrocities or that any serious opposition to the regime will thrive.
The belief that killing Hitler would change anything much is a classic example of the 'great man' theory of history, one devised and promoted by another Briton, Thomas Carlyle, adopted to some extent by Nietzsche, and of course subscribed to by the Nazis themselves. If Hitler had been killed during the rise of Nazism he would, like Horst Wessel and others, have become a Nazi martyr. After a power struggle another leader, such as Goering, would have taken charge of the NSDAP and eventually of Germany. And events would have proceeded much as before.