Moscow’s insistence that ‘fascism’ was the polar opposite of ‘communism’ found wide acceptance in socialist and liberal circles in the West. - Richard Pipes

Hitler did not have Mussolini's revolutionary socialist background... Nevertheless, he shared the socialist hatred and contempt for the 'bourgeoisie' and 'capitalism' and exploited for his purposes the powerful socialist traditions of Germany. The adjectives 'socialist' and 'worker' in the official name of Hitler's party ('The Nationalist-Socialist German Workers' Party') had not merely propagandistic value... On one occasion, in the midst of World War II, Hitler even declared that 'basically National Socialism and Marxism are the same.’

The French Jacobins were the first to realize the political potential of class resentment. Exploiting it, they conjured constant conspiracies by aristocrats and other enemies of the revolution: shortly before their fall they drafted legislation expropriating private wealth and had the unmistakable communistic implications. It was from the study of the French Revolution that its aftermath that Marx formulated the theory of class struggle as the dominant feature of history. In his theory, social antagonism was for the first time accorded moral legitimacy: hate, which Judaism condemned as self-destructive, and Christianity (in the guise of anger) treated as one of the cardinal sins, was made into a virtue.

According to Marx, the evolution of capitalism would inevitably lead to the pauperization of the proletariat and then, just as inevitably, to its radicalization. It is interesting that Bento Mussolini arrived at an identical judgment ten years later. Before the outbreak of the first World War, Mussolini had been the closest analogue to Lenin in the European socialist movement, being equally revolutionary and anti-reformist. He was the Lenin of the Italian Socialist Party with the difference that, whereas Mussolini managed to rally behind him a revolutionary majority and expel the reformers, in Russia, Lenin found himself leading a minority and forced to break away from the Social-Democratic Establishment.