WWI was a kind of turning point. Bolshevism, National Socialism and fascism are related ideologies which surfaced after the war. Fascism was the wave of the future in 1920 with its notion of government central planning.
Socialism was more ambiguous. Fascism did not become a wicked right-wing kind of ideology until the Nazis and Mussolini allied. The Bolshevists merely fumbled around. The Communist Party was a joke until the 30s when they were viewed as a force against fascists and were seen as a workers’ party. They were big winners after WWII.
Totalitarian movements are all pretty much the same. They are dead ends and generally have to be forcibly removed. But, the Soviet Union did not fall apart because of any invasion, it simply imploded from within. The Chinese government has evolved into something less brutal. Controlled thought is the main characteristic of totalitarian states. It is the way the left operates.