Beginning with the Leo XIII’s encyclical Rerum Novarum, The Principle of subsidiarity has been “among the most constant and characteristic directives of the Church's social doctrine” (Compendium of the Social Doctrine of the Church = CSDC 185). Subsidiarity requires that;
Societies of a superior order must adopt attitudes of help (“subsidium”)--therefore support, promotion, development--with respect to lower-order societies. In this way, intermediate social entities can properly perform the functions that fall to them without being required to hand them over unjustly to other social entities of a higher level, by which they would end up being absorbed and substituted, in the end seeing themselves denied their dignity and essential place. (CSDC 186).
The Church acknowledges that it may sometimes be necessary for states to intervene in to supply certain functions. The justification for such intervention is of an exceptional nature and should not continue any longer than is absolutely necessary (CSDC 188)
The Compendium tells us that a clear implication of the principle of subsidiarity is the further principle of “participation” by which “the citizen, either as an individual or in association with others, whether directly or through representation, contributes to the cultural, economic, political and social life of the civil community to which he belongs” (CSDC 189). Participation is considered one of the highest aspiration of the citizen and “one of the pillars of democratic orders and one of the major guarantees of the democratic system” (CSDC 190). In fact every democracy must by definition be participative (CSDC 190, (Centesimus annus, 46). Participation is a common duty and responsibility, fulfilled consciously with a view to the common good. Participation can be achieved in a variety of social contexts, but is essential to democracy and jeopardized by totalitarian or dictatorial regimes, “where the fundamental right to participate in public life is denied at its origin, since it is considered a threat to the state itself. (CSDC 190).