The State has the further right to intervene when particular monopolies create delays or obstacles to development. In addition to the tasks of harmonizing and guiding development, in exceptional circumstances the State can also exercise a substitute function, when social sectors or business systems are too weak or are just getting under way, and are not equal to the task at hand. Such supplementary interventions, which are justified by urgent reasons touching the common good, must be as brief as possible, so as to avoid removing permanently from society and business systems the functions which are properly theirs, and so as to avoid enlarging excessively the sphere of State intervention to the detriment of both economic and civil freedom.
Centesimus Annus