In the U.S. theological context since the 1970's, the current called "public theology" has offered a very interesting proposal for the church to be present in society. In its Catholic variant, this current is very much inspired by the American theologian David Tracy. Applied to the context of Spain, this variant could clarify the relationship between Spanish citizenship and Catholic identity. However, in order to be applied to the context of Spain, this current needs to be put in dialogue with the two other major actors in Spanish society: (1) unbelief, and (2) the Islamic tradition. The issue of unbelief has been the focus of the French moral theologian Paul Valadier. His anthropological framework based on conscience could help public theology to respond to the main secularistic critics. The work of five major modern Islamic social thinkers: Abdulaziz Sachedina, Nurcolish Majid, Adullahi An-Naim, Tariq Ramadan, and Alli Allawi --each of whom have attempted to integrate modern social values with Islamic tradition--provide resources for public theologians to address the Muslim tradition from within the Christian theological stance. By incorporating the insights of these two conversations, public theology presents a new and very interesting proposal for the Church in Spain to be present in the social debates. Integrating Valadier's concern for conscience into Tracy's critical correlational approach offers a suitable theological method. To incorporate Islam into the conversation we should put some previous conditions (the category of public religion) and we should agree on a goal for interreligious dialogue (the pluralistic common good). This method could be the way for the Church in Spain to develop a discourse rooted in Christian identity but understandable by modern Spanish pluralistic society.