1922: Mussolini is arested and charged with high treason after his failed coup.
1923: Adolf Hitler is killed in the Beer Hall Putsch. Without a leader who can stir the crowds, Public Oppion goes against the Nazi Party, and it soon disbands
What year?: Totsky becomes leader of the Soveit union
Through out the decade: Fewer people buy on margine, causeing a minor Recession rather than a Depression in 1929.
So, now all I need to do is take care of Japan and I've got it!