Abstract
In 2004 Jürgen Habermas and Joseph Ratzinger participated in a debate on the ‘pre-political moral foundations of the free-state’. Their contributions showed broad agreement on the role of religion in today’s Western secular state and on areas of collaboration and mutual enrichment between Modernity and Christianity in Europe and the West. They diverged regarding the need or not of a common cultural background prior to the existence of the polity. Their diverging point becomes all the more fascinating to the extent that the matter requires wider empirical, analytical and normative research before it can be settled. Nevertheless, the implications that derive from one or the other possibility are very different in terms, for instance, of immigration and citizenship policies. This is already clear in Europe and is becoming more evident in general in Western democracies.