I like to think that WWII had a domino effect on the rest of the 20th century's history, i.e. the true rise of the USSR, the US becoming a superpower, the collapse of the European powers, etc.
What is the longest we can delay WWII, say to 1942 or 1943? One of the biggest problems IMHO would be restraining Hitler and Stalin, but I wonder if this can be done.
What would such a WWII look like, and what after effects would it have on, well, everything?