140 The same principle of subsidiarity which governs the relations between public authorities and individuals, families and intermediate societies in a single State, must also apply to the relations between the public authority of the world community and the public authorities of each political community. The special function of this universal authority must be to evaluate and find a solution to economic, social, political and cultural problems which affect the universal common good. These are problems which, because of their extreme gravity, vastness and urgency, must be considered too difficult for the rulers of individual States to solve with any degree of success.
Source: Pacem in Terris (Vatican.va)