The essay offers a review of the studies on the link between Catholic associations, the ecclesiastical hierarchy and the Christian Democracy Party known as "collateralism". From the 1970s onwards, halfway between the Italian ecclesial and civil debate, researches on collateralism have involved the historiography on both the Catholic Church and the Christian Democratic party. From this dual perspective scholar have tried to understand, with simultaneous glances, the Catholic question and the Christian Democratic question in their complex, mutual evolution, how they have fuelled the political debate and, at the same time, the growth of the conscience of the laity. Col-lateralism was, at the same time, a matter of reflection for the ecclesial community, a target of controversy, the main argument of a wide trend in political journalism: boosting the historiography of political Catholicism, the different interpretations marked the rich hermeneutical itinerary the author hereby retraces.
Collateralism, Catholic associations, political unity of Italian Catholics, Christian Democracy, Second Vatican Council, Catholic question