Arendt critiques two ideologies in The Origins of Totalitarianism: Nazism and Marxism. The first is rather well-known and receives most of Arendt's attention. The second, though the most influential mass ideology of the 19th century, is much more obscure and her critique of it given much less time. She argues that Marxism, like Nazism, is concerned only with the movement of becoming, and that is makes men merely the tools of the movement of history. Though Arendt is more sympathetic to the workers' movements throughout her entire analysis, she believes they did not take seriously their "heritage in the French Revolution," and that Marxism as an ideology was eventually doomed to become the terror of Stalin, whether the actors knew it or not. The promised "Messianic Age" of a classless society that Marxism describes would never come to pass (446).
The likening of the classless society to the Messianic Age actually comes from a essay by Walter Benjamin, which Arendt quoted earlier in the book and which was written in 1940 (143), called Theses on the Philosophy of History (or its alternative translation, On the Concept of History). At the time of publication, Arendt was living in Berlin and had become friends with Benjamin. In the essay, Benjamin critiqued the Messianic quality and vision of progress that had been adopted by Marxism from a Marxist point of view. By bringing up this Messianism, Arendt links the two ideologies of the crisis of the 20th century, Fascism and Marxism, to the crisis of historical progress.
In contrast to Benjamin, for Arendt this is also an explicit argument against Marxism. In a conversation at a conference in Toronto in 1972, Arendt said that Marx was entirely right in his analysis of capitalism, but his mistake was endorsing it. She continues by saying that Marx's Communist Manifesto is the greatest endorsement of capitalism ever written because Marx predicts that capitalism will, negatively through socialism, bring about this Messianic Age. Arendt fundamentally disagrees with Marx's estimation of modernity and bourgeois society. She believes that it is not a road to Heaven, but a road straight to "hell." Arendt's disagreement with Marxism helps to clarify her source of hope against totalitarianism: she believes that humanity must embark on creating a form of society that is completely new and which does not arise from the existing form of society. She believes human spontaneity of political action is what might lead to such an outcome.
