§ 1. No crime can be more serious than to declare unjust wars and to wage them once declared. For if one homicide, theft, arson, or adultery is condemned by divine law, of how great a crime shall we judge him guilty who slaughters so many myriads of men, burns and reaps kingdoms, and leaves nothing in whole cities untouched by lust?
There is no purpose in recounting ancient examples. In the year 1599 the very broad and populous kingdom of Pegu was reduced to deserts; yet its king possessed so great a treasure of gold and gems that the victorious king of Arakan loaded from it seven hundred elephants and the same number of horses, and neglected the rest. Bovesius writes of that kingdom, and the account is contained in volume III of the Thesaurus of Indian Affairs: “I cannot express the grief I felt when I beheld with my own eyes those banks of the rivers planted with fruitful trees, but deserted and uncultivated, and the elegant and gilded temples overthrown from their foundations. You would think the whole kingdom deserted and uncultivated and inhabited by absolutely no one. The streets, especially those which lead to the temples, lie foul, filled with skulls and corpses: of men killed sometimes by famine, sometimes by domestic steel as they rushed into mutual slaughter, and sometimes also by royal command and cast into the river—which could scarcely be navigated even by smaller boats because of the multitude of corpses. Here I pass over cities, towns, and villages destroyed with all their inhabitants, so that no one may believe a more savage tyrant ever existed.”
The same fortune befell the most flourishing kingdom of Martaban, which was also reduced to desolation by the Siamese, as the same Thesaurus testifies. The king retained thirty thousand men with himself; two hundred thousand, stunned by fear of death, wandered through mountains and forests; every field was uncultivated and rough in the year 1599. He who gave counsel for the unjust war furnished the cause of so many evils. Therefore all the souls which perished shall be required from his soul, and the crimes of the soldiers who destroyed them shall be imputed to him.
§ 2. The causes of wars must be weighed with great care, so that the first question may be: Is the war being prepared justly? The second: Can a greater advantage be obtained from a just war than from an unjust peace? The first can be decided by theologians and jurists; the second remains uncertain until the fruit of victory. The Athenians were accustomed to hear philosophers and orators concerning the justice of a war. But if a war is undertaken unjustly, although victory follows, the wicked victor cannot remain fortunate for long.
Οὐδεὶς στρατεύων ἀδίκως σῶς ἦλθεν πάλιν.
No one who wages war unjustly returns safe.
Injustice sometimes prevails for a time, but in the end it is punished more severely. Alexander undertook many wars unjustly and conducted them uncontrollably and proudly; but he himself, together with his mother, wives, children, and whole family, paid the penalties. This would not have happened if he had remained in his own Macedonia and had not raised soldiers and centurions to such great power.
The very magnitude of the matters declares that great diligence is necessary in deciding the case, so that the justice of the war may be established. For the judge sits in the gravest cause, one which involves the fortunes of an entire kingdom and the lives of many in a single crisis.
There is a rule of law, and it is legitimate: proofs in criminal matters ought to be clearer than the noonday light. For no equity allows a defendant to fall by certain death in a doubtful cause. How, then, are so many thousands cut down when it is not clear which party has taken up arms more justly? A judge ought to follow only things proved and to adjudicate only matters which are clear: law illicitas, section veritas, On the Office of a Provincial Governor. If this is observed for a private defendant where an inheritance and little fields—or indeed the worthless life of one man—are at issue, what shall we judge must be done in great matters and with entire peoples?
But if the reasons for the adversaries and against them have equal weight, the war must now be suspended, or the matter must be investigated more accurately and the rule observed which Tholosanus counsels in his Syntagma, Book XLVIII, chapter 9, section 14: “Wherefore, if the defendant and plaintiff prove equally, and the witnesses and other productions are equivalent, the matter returns to doubt and to its first condition, whence the defendant is absolved—unless the plaintiff supports the more favorable cause. For judgment must be given in doubtful matters in favor of things favorable: as for liberty, in an action concerning an undutiful will, for marriage, and for a dowry. Nevertheless, in criminal causes a concurrence of proofs rarely occurs, for in them the defendant is not admitted to prove a negative so long as the plaintiff or accuser can prove his case. For a canonical proof is not introduced against proofs. Yet this is observed: if, while the defendant is heard in a criminal cause, he alleges certain facts, as they call them, or circumstances that attenuate or restrict the quality of the offense, proof is taken concerning these when separately extracted. A new investigation is also made by virtue of the judge’s office when the proof on either side is doubtful, so that certain knowledge of the truth may be had.”
A much greater investigation is fitting for one about to wage war. A light and perfunctory consideration has no force in this matter, for only an error difficult to avoid excuses its author. He will examine the matter not only through his own counselors but through universities, other friends, and princes. And if the rights of the parties are obscure, judgment must be made for the defendant, not the plaintiff.
§ 3. If war is declared upon some prince or state, the cause must be weighed. If the adversary possesses a just cause, satisfaction must be given to him. If, after all diligence has been applied, the cause remains doubtful, the prince can offer himself for a more exact discussion; if he is attacked by war, he can defend himself, for he is not bound to abandon his right merely because his right is doubtful. Further, he who makes war on the basis of a doubtful right commits an injury; therefore, the man who previously defended a doubtful cause now wages a just war.
§ 4. Here too that principle remains: in doubt, the cause of the possessor is better. For this holds in every cause, but especially in a criminal cause, since sentence concerning life is not rendered from obscure matters; but he who declares war has already pronounced judgment concerning life. Nor do princes here have more right over princes than subjects have over subjects.
§ 5. Nevertheless, the man who does not possess can request a judge and demand by right that, since the cause of each is doubtful, it be judged in common and that a part be given to the one who does not possess, or, if the thing cannot be divided, compensation. This has place, however, if the cause of the nonpossessor is more probable; for they are no longer equal, and therefore the condition of the possessor is not better. Nor is the nonpossessor bound to abandon the more probable right. Otherwise, if the possessor had the slightest doubt and the other the most probable cause, the latter could do nothing, which is unjust. But if in such a cause the possessor is unwilling to give anything, he commits an injury and can therefore be attacked in war by his adversary.
§ 6. Nor do I exempt soldiers, especially tribunes and centurions, from some inquiry into right and equity. For if the war is manifestly just, all can serve in it; if the injustice is clear, no one can give his name for military service. If the cause is doubtful, soldiers who are subjects, bound to fixed pay, and vassals can follow a cause that is doubtful. Thus Saint Augustine, Against Faustus, Book XXII, chapter 75: “For if a just man happens to serve under a sacrilegious king, he can rightly fight at his command when it is certain that what is commanded is not against God’s command, or when it is not certain whether it is so; in such a way that perhaps the king is made guilty by the injustice of commanding, while the order of servitude shows the soldier to be innocent.”
For soldiers, when they execute the sentence of a judge, choose the safer part when they follow the sentence of their prince. Finally, soldiers are bound to follow the prince; for by refusing the oath they would add strength to the enemy and betray the state. Certainly, in doubt one ought to favor one’s country rather than its enemies. Finally, it is not customary to summon an unorganized multitude to judge the cause. The reasoning is different for commanders who, when they are summoned as counselors, are compelled to judge the justice of the cause seriously. But if it is evident to soldiers and vassals that the prince doubts the justice of his cause, they ought not to enroll for military service, because they know that the war is unjust. For it is unjust to judge concerning another’s life when the cause is doubtful.
§ 7. Soldiers who are not subjects cannot serve in a doubtful cause, because the war does not concern them and they cannot voluntarily involve themselves in a doubtful matter. Further, without any necessity they expose themselves to the danger of inflicting injury upon another prince, whereas by abstaining they avoid that danger.
Ordinarily, however, soldiers of good conscience do not sin here. For those who wage wars put forward the most specious causes, which appear plainly necessary. Further, when a king or prince is of good name, they rightly presume that he does not undertake unjust wars, that he has examined the cause accurately, and that it has been approved by prudent and upright men. Conrad Lancellotus says that laws existed before arms; but I believe that laws were made for laying down arms or not taking them up. After arms, laws were thus enacted.