Present changes in religion as a school subject and Religious Education as a research field are generally, and also by most of the authors in this volume, explained by changes in the subject matter of religion, due to increasing religious pluralism. In a functional perspective, the school subject of religion contributes to the legitimizing function of school education for society and its institutions. With religion being a central moral negotiation ground in society, moral debate in society (and not only religious subject matter), and its constitutional role for Religious Education as a research field can explain further diversity of approaches to research in Religious Education. This also raises questions about the field's vulnerability to public instrumentalization and about moral negotiation and its place in religious education didactics.