Pacem in Terris §72

⁷² Moreover, the relations of citizens with each other, of citizens and intermediate groups with public authorities, and the relations between public authorities of the same State, are sometimes seen to be of so ambiguous and explosive a nature, that they are not susceptible of being regulated by any hard and fast system of laws. In such cases, if the authorities want to preserve the State's juridical system intact—in itself and in its application to specific cases—and if they want to minister to the principal needs of society, adapt the laws to the conditions of modern life and seek solutions to new problems, then it is essential that they have a clear idea of the nature and limits of their own legitimate spheres of action. Their calmness, integrity, clear sightedness and perseverance must be such that they will recognize at once what is needed in a given situation, and act with promptness and efficiency.(50)