Hitler did a better job than Stalin of accomplishing Lenin's totalitarian promises—better, too, than Mussolini. - François Furet

To understand this relationship we may start with what has become an accepted observation: Stalinized Bolshevism and National Socialism constitute the two examples of twentieth-century totalitarian regimes. Not only were they comparable, but they form a political category of their own, which has become established since Hannah Arendt.

What was new about Hitler and Stalin was what Friedrich Meinecke, in an attempt shortly after World War II to express his horror at Hitler’s moral nihilism, called a ‘ Machiavellianism of the masses'.

After all, in my country as well, and in democratic Europe, fascism, a fortiori in its Nazi form, was a more or less taboo subject for the historian. I mean that the moral condemnation directed against the two regimes precluded not only studying them, but also understanding the popularity they enjoyed between the two wars. And that taboo that impeded all types of comparative analysis, and even the idea of an interdependence between communism and fascism, was just as great, even if it did not have the same historical or cultural reasons.