The aim of the article is to compare two concepts of the social contract – formulated by Immanuel Kant and Jean Jacques Rousseau respectively – in the context of their philosophical diagnoses regarding human nature, culture, politics and the historical dynamics of civilization. The author focusses on the essence of the impact Du contrat social has on Kant and the extent to which he manages to overcome the tension between the modern Republican idea – which he develops on this basis – and the tradition of classical liberalism, which he continues to follow. He considers Rousseau’s model with regard to the conflict between the democratic principle of people’s sovereignty and the Republican rule of law in discussions with Hegel, Arendt, Habermas and in reference to the French Revolution. Next, he conducts a critical analysis of the Kantian project of Rechtsstaat in light of its conceptual dependence on Rousseau – the founding of this project on the liberal tradition turns out to be problematic and burdened with ideological symptoms. Since Kant’s thought lies at the root of the modern concept of liberal rule of law, these symptoms show the limitations of Rechtsstaat resulting from its own normative assumptions.