According to Pope John, government itself can function virtuously under many different forms::
67. For the rest, it is not possible to give a general ruling on the most suitable form of government, or the ways in which civil authorities can most effectively fulfill their legislative, administrative, and judicial functions.
Some forms will work across all human cultures. But certain aspects particular to a nation or culture must be provided the people:
68. In determining what form a particular government shall take, and the way in which it shall function, a major consideration will be the prevailing circumstances and the condition of the people; and these are things which vary in different places and at different times.
We think, however, that it is in keeping with human nature for the State to be given a form which embodies a threefold division of public office properly corresponding to the three main functions of public authority. In such a State a precise legal framework is provided, not only for the official functions of government, but also for the mutual relations between citizens and public officials. This will obviously afford sure protection to citizens, both in the safeguarding of their rights and in the fulfilment of their duties.
Unfairness and injustice contributes as much as anything to the instability of society:
69. If, however, this juridical and political structure is to realize its potential benefits, it is absolutely essential that public officials do their utmost to solve the problems that arise; and they must do so by using policies and techniques which it is within their competence to implement, and which suit the actual condition of the State. It is also essential that, despite constantly changing conditions, legislators never disregard the moral law or constitutional provision, nor act at variance with the exigencies of the common good. And as justice must be the guiding principle in the administration of the State, and executives must thoroughly understand the law and carefully weigh all attendant circumstances, so too in the courts: justice must be administered impartially, and judges must be wholly incorrupt and uninfluenced by the solicitations of interested parties. The good order of society also requires that individuals and subsidiary groups within the State be effectively protected by law in the affirmation of their rights and the performance of their duties, both in their relations with each other and with government officials.( Cf. Pius XII’s broadcast message, Christmas 1942, AAS 35 (1943) 21)
We have certainly suffered this in the United States, and it seems we have not totally escaped it today. The situation seems worse in most Latin American countries. Friends who visit and live there report that it has been particularly difficult to emerge into the status of peaceable and stable nationhood because of widespread corruption and the lack of confidence in the basic principle of fairness.