1. The moral force of this sort of law comes from the moral foundation of the authority of the community, discussed in B above. To the extent civil society really is a community, its members have a nonabsolute duty to obey the decisions of its authorities.
2. But civil society is complex even insofar as it is a community. For some of its members—those incapable of making a free commitment—it functions wholly as a natural society, an extended family as it were. As far as others are concerned, it derives at least part of its character as a community from their morally upright commitment to its common purposes. The extent to which the authority of governments is grounded in the consent of the governed varies at different times and places, and also with different groups of citizens. And aliens voluntarily present in a civil society share in a limited way in its community, on a contractual basis, perhaps with no commitment at all to the society’s common purposes.
3. Yet civil society is not without moral force even in regard to those of its members who do not consent; its authority can morally bind those who wrongfully refuse to commit themselves to community. Also, under some conditions—when common action is morally required and only certain persons are in a position to direct it—civil society rightfully functions in the manner of a “family” toward more of its members than usual. That the consent of the governed is absent at such times does not deprive government of its just power or nullify the responsibility of citizens to obey the law.
4. The duty to obey the kind of laws under consideration here can be qualified in two ways. First, a law can lack authority due to some defect in it or in the way it was arrived at. Second, a law can be nonapplicable in particular cases.
5. An authoritative decision of civil society contains a defect which causes it to lack moral authority if it would require a person to do something inconsistent with a moral absolute or would involve a person in a social action inconsistent with any of the modes of responsibility (see S.t., 1–2, q. 96, a. 4). For example, Nazi laws which directed people to kill the innocent and carry on a useless war to the death were morally defective in a radical way.
6. Less radically, a decision can be morally defective in regard to the process by which it was reached. This can happen in three ways. First, the constitution which it implements can be defective, as was the original United States Constitution in its acceptance of slavery. Second, the decision can be inconsistent with the constitution, as laws enforcing racial segregation in the United States were (and were found to be in 1954 and subsequently). Third, the procedure by which the decision was made can be unfair, as is often the case in the formulating of tax laws, which reflect political pressures and favoritism more than judgments concerning what is fair and best for the society as a whole.
Even so, a morally responsible citizen will realize that life in political society is inevitable, that the society in which he or she lives is not altogether unjust, that many of its activities ought to be supported, and that other citizens, including those in worse economic condition, will suffer if one does not contribute one’s legally specified share. This consideration shows that one cannot easily be morally certain that a defect in the process by which a law is made is sufficient to undermine its moral force.10
7. A law of civil society also lacks moral authority if it is inapplicable. Although not defective in itself, an authoritative directive sometimes need not be obeyed because of specifying factors, which can be of three kinds.
8. First, sometimes a law requires one to do something incompatible with another duty one has. (Conflicts of duties will be discussed in 12‑E.)
9. Second, sometimes a law originally made for a reasonable purpose is undercut because changed conditions render compliance irrelevant to its purpose. Antiquated ordinances which a government could not reasonably try to enforce need not be obeyed (see S.t., 1–2, q. 97, a. 3).
10. Third, a law can be inapplicable because of exceptions—that is, under specific conditions, not mentioned and perhaps not even anticipated by the lawmaker, it could not reasonably have been meant to apply. In emergencies, for example, property laws can be set aside to save human lives, for no authority can reasonably wish the system of ownership to block the more basic good of human life to whose service property mainly is directed. In such a case, one violates the letter of the law to preserve its spirit. Such a reasonable judgment to act against the law’s letter is called “epikeia” (see S.t., 2–2, q. 120).
11. Lacking moral certitude that a law is without moral authority or is inapplicable, an upright person will observe the nonabsolute norm requiring obedience. One must bear in mind that a law is not altogether defective and nonbinding merely because it is not perfectly and ideally just. Moreover, although the practice of epikeia can be sound, it is very often misunderstood and grossly abused. Then too, even if there is no duty to obey, Christians will often find reason to comply with laws when it is not wrong to do so, because a law-abiding style of life generally furthers their Christian vocation.
Although analogous to the qualification of nonabsolute moral norms by the addition of further specifications, epikeia really belongs only in the area of positive law, when one is morally obliged to make an exception to an authoritative decision, which one has no authority to revise and refine.11
Those subject to law are not justified in making exceptions simply because they personally would have made a different law. If such individualism were permissible, social authority would mean nothing. Nor are those subject to law justified in making exceptions whenever they think a different course of action would be considered reasonable by the authority if it knew all the conditions. For members of a society to make such judgments would produce too much diversity and leave the community without a common framework for its common action.
The condition which justifies exceptions is more stringent: One must be able to say sincerely that if the lawmaking authority knew the circumstances, it would surely want the exception to be made (see S.t., 1–2, q. 96, a. 6; q. 100, a. 8).
10. Proponents of natural law often argue that an unjust positive law is no law at all. In one sense this is surely true, but in another not. On this point, see Finnis, op. cit., 354–66, esp. 361–62, 367, for a discussion of collateral sources of obligation to obey unjust laws. See also S.t., 1–2, q. 96, a. 4.
11. See Lawrence J. Riley, The History, Nature, and Use of Epikeia in Moral Theology (Washington, D.C.: Catholic University of America Press, 1948), 276–85.