The Introduction contextualizes the research and formulates the main hypothesis guiding this book: in a period of polarized relations between religion and politics, there is a Catholic action repertoire which avoids this binary confrontation and which, in contrast, is characterized by its mediating dimension. This mediation repertoire is distinct from a Catholic repertoire of confrontation positioned according to principles of resistance to political reforms to family, education and bioethics policies. On these last issues, Catholic campaigns receive a great deal of media coverage and find natural political interlocutors on the conservative side of the arguments. The Catholic mediation repertoire, in contrast, receives little publicity and is expressed in a discreet but structuring way to address different public problems: exclusion and poverty, social inequalities, the integration of migrants and ethno-territorial conflicts. However, and beyond its overt depoliticization, the mediating work of the Church nonetheless remains eminently political in that it intervenes directly in territorial public debates.