Jonathan McIntosh (Ph.D., University of Dallas) is a Fellow of Humanities at New Saint Andrews College in Moscow, Idaho, where he teaches on the history of western political and economic thought, philosophical theology, natural law ethics, Aquinas, Anselm, and J.R.R. Tolkien. He is the author of The Flame Imperishable: Tolkien, St. Thomas, and the Metaphysics of Faërie, and blogs at The Natural Law Libertarian and The Flame Imperishable.
What, precisely, is human law able to do? What is the reach or “power” of human law? This is the next topic St. Thomas Aquinas (1225-1274) takes up in his “Treatise on Law.” Unsurprisingly, his answer to these questions reflects both the libertarian and the anti-libertarian strains in his thought that we’ve been tracing throughout this series of articles so far.
One question Aquinas poses that is of particular interest to us here asks whether human law has the power of repressing all human vice (ST I-II.96.2). Although Aquinas believes, as we have seen, that one of the main effects of law is to make men good, he denies here that law is able to forbid all sin, and his explanation leads him into one of his most libertarian statements in all of his writings. Law, he states, must be suitably tailored to the moral condition of the subjects that it regulates, meaning that the less virtuous a society is, the more permissive its law needs to be. Since most human beings, however, are imperfect in virtue, the vices which law characteristically ought to prohibit are only “the more grievous” kind which most men are able to avoid, such as murder and theft, and which Aquinas describes as involving the “hurt” and “assailing” of others, in which “one’s neighbor is injured.” Thus, although the way Aquinas gets there is utilitarian in the extreme, his conclusion is fully libertarian: law seeks to prohibit not all vices, but primarily those that involve aggression against others.
Aquinas’s libertarian moment, however, is short lived, for in the very next section he poses the question of whether law has the power of commanding any act of virtue, to which he answers “yes” (ST I-II.96.3). His view is not that law can command all acts of all the virtues all the time, for this would amount to claiming that law can prohibit all vices after all. Rather, his claim is the slightly more modest one that, in principle, there is no virtue or act of virtue that is in inherently “off the table” where law is concerned. His reasoning is that because all the virtues are ordered towards and contributory to the common good, and the common good is the whole aim or purpose of law, there can be no virtue that is off limits to law’s purview or prescriptive activity. Nevertheless, Aquinas recognizes that, practically speaking, not every virtue is an equal priority to the common good and therefore of equal priority to the law.
The libertarian need have no objection to Aquinas’s claim that all virtue and all acts of virtue contribute to the common good. Where the objection comes in, as we have seen in earlier passages, is with Aquinas’s construing the common good with which coercive human law is concerned in so broad a manner. As we have just seen, Aquinas denies that human law has the power to regulate all vice, thereby implying that the common good able to be achieved by coercive human law is not and cannot be the thick one of communal happiness and positive virtue, but the comparatively thin (and libertarian) one of merely prohibiting those more egregious acts of aggression against others that make civil society to be impossible. In these two consecutive claims about the power of human law, accordingly, we see the tension, and really, the contradiction, at the heart of Aquinas’s entire political philosophy as a whole, namely that between his libertarian and realist appreciation of the radical limits of coercive human law on the one hand, and his Aristotelian and naïve optimism about its purported abilities on the other.
Aquinas’s next question on the power of human law involves him in swinging once again back in a more appreciably libertarian direction, as he asks whether human law has the power to bind a man, not just in his bodily actions, but now in the inner recesses of his own conscience (ST I-II.96.4). Do man-made laws have the ability morally, as opposed to merely physically, to compel or oblige action and obedience on the part of other men? Aquinas answers by stating that laws oblige only so far as they are just, but devotes even more space to discussing those circumstances in which a law is unjust, and hence not binding on the conscience. This occurs when a law is either contrary to the common good, accrues only to the private good of the ruler, goes beyond the authority of the ruler, or imposes burdens unequally on the community. Nevertheless, even when a law is unjust and so does not bind the conscience directly, Aquinas allows that there may nevertheless be an obligation to obey the law, not because it is a law, but in order to avoid offending the conscience of others or causing a public scandal.
Aquinas’s teaching on law and conscience is significant as it contains arguably his most direct instruction on the important question of civil disobedience: when is it morally permissible for individuals to disregard the commands of civil government? Related to this, it also contains perhaps his most direct confrontation with the doctrine of legal positivism so dominant in the practice of law and politics today. According to legal positivism, a law is any rule that has been enacted and is enforced by a recognized legal authority, with the implication that justice is whatever the law says is just. For Aquinas, by contrast, whether something is a law is not a matter of the lawmakers merely saying that it is a law or that it is just. Rather, a law is only law, and hence binding on the conscience, insofar as it is just, where the justice of a law is determined not by the law itself but by such external and objective factors as whether the law is truly ordered to the common good, made by one with real authority, and equitably distributing the burden of law throughout society. Here Aquinas may also be seen as espousing a form of philosophical vigilantism, insofar as he implicitly recognizes the responsibility that every individual inescapably has, as a free, rational agent, to pass judgment on the law and to determine its actual lawfulness as a law.
We conclude our consideration of Aquinas’s discussion of law’s power with his question on whether the power of law is over all men, good and bad alike, or only over the wicked (ST I-II.96.5). Insofar as law is a rule of human action, he says that it applies to all men, but insofar as it is a rule of human action that comes with coercive power, he says that law only applies to the wicked, since the virtuous are those who keep the law out of principle and not force. Here Aquinas may be seen attempting to resolve the ambiguity we have seen in his philosophy of law thus far, namely his attempt to have law function simultaneously as a coordinative principle for the whole community but as coercive principle only for the wicked. To this, however, the libertarian might respond by asking whether it is reasonable to assign one and the same institution of human law both of these purposes at once. Granted that all the members of the community need rules, customs, and the like to better coordinate their actions towards many higher (and lower) order goods, and granted that some members of the community, namely the wicked, need coercion to deter them from acts of aggression against others, the question remains as to why the coercion used in the latter should also be used in the case of the former. Given, in other words, Aquinas’s own acknowledgment of the inherent limits of the use of coercive human law, and his general view of the importance of free, rational human beings being able to direct their own actions, why should we expect the rules designed for the harmonious collaboration of society to be enforced by the same coercive means as those laws intended to protect members of society from acts of aggression? Aquinas never answers this question, but it is one that cuts to the heart of the debate between his political philosophy and that of the libertarian.
 An early expression of such legal positivism is Thrasymachus in book one of Plato’s Republic when he defines justice as “the advantage of the stronger.” Law and justice, in other words, are simply whatever those in political authority say that they are.
 Elsewhere Aquinas himself implies the possibility of a more libertarian division of labor between the two different kinds of rule for human action—the coordinative and the coercive—being suggested here. Following Aristotle, for example, Aquinas routinely distinguishes between “royal” or “political” rule on the one hand, in which he says subjects are not forced to obey but are actually free and even have a “right” to disobey, and “despotic” rule on the other, where there is no such freedom. An application of this perspective would seem to be as follows: whereas those laws protecting against acts of aggression are and ought to be “despotic” in their use of coercion, those “royal” directives otherwise responsible for directing the community towards the common good ought to be ones that the wise and virtuous can and sometimes will depart from.