The paper traces the development from the medieval, traditional union, through the modern disunion, toward a possible post-modern reunion of the sacred and the profane. It concentrates on the modern disunion and conflict between the religious and the secular, revelation and enlightenment, faith and autonomous reason in the Western world and beyond. It deals specifically with Christianity and the modern age, particularly liberalism, socialism and fascism of the 2Oth and the 21st centuries. The problematic inclination of Western Catholicism toward fascism, motivated by the fear of and hate against socialism and communism in the 20th century, and toward exclusive, authoritarian, and totalitarian populism and identitarianism in the 21st. century, is analyzed, compared and critiqued. Solutions to the problem are suggested on the basis of the Critical Theory of Religion and Society, derived from the Critical Theory of Society of the Frankfurt School. The critical theory and praxis should help to reconcile the culture wars which are continually produced by the modern antagonism between the religious and the secular, and to prepare the way toward post-modern, alternative Future III - the freedom of All on the basis of the collective appropriation of collective surplus value. Distribution and recognition problems are equally taken seriously.