The British Guardian newspaper website has this terribly newsworthy piece:

Time travellers: please don’t kill Hitler

Gives the usual set of reasons why time travellers shouldn’t go gunning for Adolf. But perhaps the most important reason isn’t given: a world without Hitler might well have been *worse.* Consider this hypothetical:

1918: Corporal Hitler gets whacked deader’n Disco on the battlefield. Germany still loses WWI.

1920’s: Weimar Germany is a badly-run pile of awful. On the political fringes, you have the National Socialists on the Left, and the Communists on the far Left. These two groups of idiots have the same idiot street battles they had in Real History. But sans Hitler, the Nazis never really get anywhere. The fascist movement in Germany remains a disunited mess of knuckleheads. But with Soviet assistance, the Commies gain in power, effectively unopposed by the Nazis.

1930’s: Instead of being taken over by fascism, Germany is taken over by Communists. With a strong Commie Germany, France will probably slip into at least strong socialism by the late 30’s/early 40’s.

So when Stalin’s war does break out, likely in the early 1940’s with an invasion of Poland to solidify Communism in eastern Europe, Germany will likely be on their side. France almost certainly won’t go to war with the Soviets… they certainly didn’t in Real World 1939 when the USSR invaded Poland (people forget that Germany invaded Poland from the west with the USSR simultaneously invading from the east). So by the mid/late 1940’s, Europe will probably be one gigantic Soviet all the way through France, with a very, very nervous Britain offshore (not sure where Spain would be… without the Nazis, the Spanish Civil War might well have resulted in a Commie Spain.

Japan probably would have been just as militaristic and expansionist as IRL. So the US and japan probably would have tangled at about the same time. Unclear what would have happened in Europe. But if history is any guide, you can expect the death toll from Communist Europe, even without a giant war, to approximate the death toll of World War II. There would be vast numbers of rich/well-off/middle-class Germans and French and Spaniards who would be given the Kulak treatment. Famines would wipe out more as local agriculture is taken over by Five Year Plans; the Soviets would very likely put Nazi dream of “Lebensraum” to shame as western Europeans are shuffled off East, and Russians and Siberians and such are shoved West. With the guts of Europe eaten by Stalinism, would Italy, Scandinavia, Portugal, Switzerland survive? There would be a whole lot of people in those countries with a whole lot of money, you could expect pretty much most of them to die, followed by many more as chaos and central planning erupts.

And then there would be war. Somewhere along the line, you can bet that a Europe-wise Stalinist state would decide that it was time for Britain to join the club. If the US got sucked into it, you’d add the WWII European theater death toll on top of the tens of millions dead due to Communism. Yay.

In the Pacific: without Hitler to suck America into the European war, the US focuses on Japan. Most likely, this would mean that the US would make faster progress in the push to Japan. But there’s a problem: probably no nukes, or at least delayed. For some reason, a lot of Americans of the time saw Fascism as substantially worse than Communism. And Nazisms weird-ass focus on Da Jooooz aided the US’s atomic program. So… seems fair to assume that the Manhattan Project would have been considerably slowed. And so America would have had little choice but an invasion of Japan… with millions dead on both sides. And this assumes the much richer, much stronger Soviets don’t invade Japan their own selves.

So… yeah. Don’t kill Hitler. If a time traveller wants to kill someone… start with Marx. Then Lenin, then Stalin. *Then* Hitler. Kinda difficult to imagine what European history would have been without this pack of a-holes, but it’s hard to imagine it would’ve been worse.