In "The Children of Light and the Children of Darkness" of 1944, not only was Reinhold Niebuhr (1892-1971) implementing a harsh criticism against the traditional defense of democracy offered by the liberal thought but he also formulated a justification of it starting from the Christian tradition. However, as is evident in many others of his writings, the Protestant theologian did not aim to identify Christianity as a necessary foundation of this political regime. This article analyzes his attempt to demystify and desacralise democracy. Niebuhr wants to propose a more realistic and secular perspective to better understand the method and the ethos of democracy, through the rediscovery of the Christian view of human nature and history.