The famous American Protestant theologian and political thinker Reinhold Niebuhr (1892-1971) was one of the leading figures in reintroducing the notion of sin and original sin in the public sphere. In his theological magnum opus, The Nature and Destiny of Man (1941, 1943), Niebuhr provides a specific - more Augustinian than Thomistic - understanding of human nature in which he heavily stresses the element of sin and original sin. Published during the Second World War, Niebuhr's explanation seemed justified. Furthermore, this perspective served as a ground for his mature social and political writings, such as The Children of Light and the Children of Darkness (1944) and Christian Realism and Political Problems (1953). Interestingly, in his last book, Man's Nature and His Communities (1965), Niebuhr maintains the empirical evidence behind the fact of original sin. Nevertheless, he assumes using it was a pedagogical error since it has lost its meaning for the secular audience. After a brief introduction to Niebuhr's theological anthropology, focusing on sin and original sin, this dilemma of receptivity in current politics will be elaborated.