A paradoxical contention
On the other hand, there is a dispute as to whether or not, if a case of this kind should arise, the term “public war” would be applicable. I myself see no objection to this application of the term. For such wars are supported by the will of the state; and the state’s will, whether expressly or tacitly indicated, ought assuredly to be regarded as authority for the waging of war, as has been argued not only by Ciceroa but also (among the theologians) by Cajetan,b who bases his contention on what is undoubtedly an ancient formula: “Let the welfare of the people be the supreme law.” Indeed, this very question has been weighed on various occasions, both in Rome and elsewhere. For by the law of the Quirites, it was impossible (generally speaking, at least) for war to be undertaken otherwise than through a decree of the People or of the Senate. Nevertheless, when Gnaeus Manlius made war upon the Galatians, for cause but without any previous declaration of hostilities, he was not only acquitted after being accused; he was even rewarded with triumphal honours. Again, Cato’s opinion was repudiated when he characterized as “private” the war undertaken by Julius Caesar (who had been sent into Gaul with supreme power) against Ariovistus and the Germans, and the war of that same Caesar against the Britons. I, for my part, do not doubt that both Manlius and Caesar could have been defended on this ground, namely, that whenever war has been publicly declared upon any nation, all persons of potential aid to that nation would seem to be tacitly included under the declaration. In fact, it is my belief that even the war waged against Antony by Decimus Brutus, as Governor of Gaul, was a public war. Accordingly, in the light of the foregoing arguments and examples, I am moved to reject the authority of Innocentc and that [29] of Bartolus,d who follows him. Certainly their authority should carry little weight in cases relating to public law or to the law of nations; especially in view of the fact that the opposite opinion does not lack adherents, even among the Spaniards,e a race by no means to be despised in the field of jurisprudence. In particular, it may be noted that there is no one who does not concede the truth of this very opinion in relation to reprisals,a which may be regarded as a form of war.
Now, just as private individuals are rightly drawn into war by other private individuals, so also a given state or magistrate may be joined in warfare not only by such individuals but even by another state or magistrate.b Here we have the origin of allied forces. In regard to this institution, the Greeksc drew a neat distinction, employing the terms ξυμμαχίαν and ἐπιμαχίαν, which refer respectively to alliances established with a view to any cause of war whatsoever, and to those formed for defensive purposes only, in accordance with the First Law.
Subjects (that is to say, those persons who are bound by the laws of a state) likewise serve as instruments of public warfare. This is the sense, in part, of the Seventh and Eighth Laws, and also of the Fourth Rule. Consequently, no subject should be excepted from this category, save perchance on the basis of a special law or because of the customs of the particular state concerned: as slaves, for example, were excepted under Roman law and clerics under pontifical law, though for diverse reasons. But the extent to which subjects participate in public warfare is a matter which will be discussed in another context.d
Conclusion V, Article II
For the present, our inquiry is concerned solely with the rights of [different classes of] persons [viewed as potential participants in public warfare], and those rights may be summarized as follows : Public wars are justly waged by a state or by a magistrate in accordance with his rank, both in conjunction with an allied state or allied magistrate, and through the agency of subjects.
Concerning the Subject-Matter of War for What Cause and in What Circumstances Is War Justly Waged?
Article III. What constitutes just subject-matter of war, in a causal sense, for subjects?
Corollary to Question VI. Can there be a war that is just for both parties?
Article I. With respect to voluntary agents?
Article II. With respect to subjects?
Let us consider next the following question: For what cause, and against whom, are wars waged? And let us devote the first part of our inquiry to what is properly termed the “cause of war,” although Aristotlea refers to the same concept as the “origin of war” and others, more specifically, as its πρόφασις [pretext or occasion].a
In view of the fact, then, that a just war consists in the execution of a right,b the matter regarding which a just war is waged must of necessity be a right.c
In this connexion, however, it should be noted that, although two types of belligerents have been mentioned above—the one type, voluntary, and the other (to which we applied the term “subjects”), instrumental, so to speak—the concept of “right” is not to be interpreted in the same way for the two cases. For subjects as such enjoy a right not absolutely, but in a relative sense, as the Scholastics have maintained. Indeed, in the strict sense of the term, a right pertains only to those who act voluntarily.d Furthermore, in order that a right may exist, it is necessary for volition to spring from an intellectual act of understanding, and that understanding must in turn be derived from truth itself. For the ancients were not unjustified in defining law as “right reason.” Those persons, moreover, who give the command for war, are properly admonished not to employ this last weapon of necessity unless such a course of action is based upon just cause.e Cicerof has said: “Those wars are unjust which have been undertaken without cause.”
Now, every right that we possess may be referred to one of four laws: the First, the Second, the Fifth, and the Sixth. For the Third and Fourth Laws, when interpreted from the standpoint of personal welfare, differ not at all from the First and Second, save only in the fact that the terms are reversed;