CATECHISM OF THE CATHOLIC CHURCH
SECOND EDITION

Paragraphs 1902–1906

1902 Authority does not derive its moral legitimacy from itself. It must not behave in a despotic manner, but must act for the common good as a "moral force based on freedom and a sense of responsibility":

A human law has the character of law to the extent that it accords with right reason, and thus derives from the eternal law. Insofar as it falls short of right reason it is said to be an unjust law, and thus has not so much the nature of law as of a kind of violence.

1903 Authority is exercised legitimately only when it seeks the common good of the group concerned and if it employs morally licit means to attain it. If rulers were to enact unjust laws or take measures contrary to the moral order, such arrangements would not be binding in conscience. In such a case, "authority breaks down completely and results in shameful abuse."
1904 "It is preferable that each power be balanced by other powers and by other spheres of responsibility which keep it within proper bounds. This is the principle of the 'rule of law,' in which the law is sovereign and not the arbitrary will of men."
1905 In keeping with the social nature of man, the good of each individual is necessarily related to the common good, which in turn can be defined only in reference to the human person:

Do not live entirely isolated, having retreated into yourselves, as if you were already justified, but gather instead to seek the common good together.

1906 By common good is to be understood "the sum total of social conditions which allow people, either as groups or as individuals, to reach their fulfillment more fully and more easily." The common good concerns the life of all. It calls for prudence from each, and even more from those who exercise the office of authority. It consists of three essential elements: