The conditions of a just war

The conditions on which war may be lawfully waged are three:

(a) The public authority of a sovereign state is requisite to declare war, for war, except in just defence, cannot be made on private authority, or by a less than sovereign state; for private persons and subject states can always have recourse to higher authority for the vindication of their rights.

(b) A just and weighty cause is necessary, for the cause should be such as to outweigh the grave evils and risks which always accompany war. Such causes, in the judgement of divines, are: the retaking of a conquered country or rebellious province, the avenging of a grave insult or injury offered to the State, the freeing of the unjustly oppressed, the refusal of infidel states to allow the Gospel to be preached in their dominions. There is considerable difference of opinion as to whether certainty of the existence of a sufficient cause is required or not for the lawfulness of a war. Some divines hold that a probability of right is sufficient, for with such a probable right a private person may commence an action at law, and states should not be in a worse position than private persons in the prosecution of their claims. However, on account of the grave public evils connected with war, and because it is unlawful to deprive another of what he possesses on the ground that it is only probably mine, it would seem that at least a more probable right or even a moral certainty of right is required on the side of the state that begins the war.

(c) There must be an upright intention of advancing the cause of good or preventing evil. Mere delight in the excitement of war, or the desire of showing one’s prowess or obtaining promotion, would not justify war.

When the end of the war has been sufficiently obtained the victorious party should be ready to make peace on proper guarantees being given.

Is war lawful? - The lawfulness of defensive war is clear from this, that if it is lawful for a private man to repel force by force, the same certainly will be lawful for the whole society.

But the lawfulness of offensive war, if the due conditions concur, is clear both from the common authority of Catholics and because by natural law it is lawful not only to ward off an injury while it is being inflicted unjustly on someone, but also to vindicate and remove it by public authority after it has been inflicted, lest it be inflicted again thereafter. Therefore supreme Princes, who on earth do not have a higher judge, can vindicate injuries inflicted on them by another Prince; and this cannot be done except through offensive war. Therefore. C. Iustum 1, c. 23, q. 2; C. Dominus 2 ib.; Struggl 41; Ithur. Cas. 40, n. 13; L. 402; S. Th. 2. 2, q. 40, a. 1; E. M. Consequently war is lawful for bringing help to another people which is waging a lawful war. E. M. 757.

What are the conditions for beginning, continuing, and ending war lawfully and justly? - R. To the 1st: 1. Public authority, that is, supreme authority, recognizing no other superior in civil matters. The reason is that where a greater authority is had, this must judge concerning the dispute. 2. A just and grave cause, which is preponderant over the inconveniences going to follow from war, for example, a kingdom or province to be recovered, or a grave injury to the commonwealth to be warded off, or a rebellion of subjects to be repressed, etc. For since from war so many evils come to the body and soul of many, it is not to be attempted except in extremes. 3. Morally certain right. The reason is: 1. because a possessor in good faith cannot be despoiled of the thing possessed, unless it is established that he unjustly retains it. 2. Because for positing the cause of most grave evils, both of private persons and of society itself, such as killings, injustices, corruptions of morals, and other such things, which ordinarily follow war, moral certainty of one's right seems to be required. Thus far more probably and more truly, St. Liguori 404, Pal., Tamb., and others against many, of whom some think that only greater probability suffices, others that equal probability suffices. But theologians commonly teach that lesser probability by no means suffices. 4. That before war, condign satisfaction be demanded from the adverse party; if it is offered, it must be accepted from justice, for where war ceases to be necessary, it also ceases to be just. 5. Right intention is required, namely that good be promoted and evil avoided, not by cupidity or cruelty, but by zeal for peace. L. 403, 405; S. Th. 2. 2, q. 10, a. 8; q. 40, a. 1; Verricelli tr. de Apost. Mission. t. 13, q. 128, s. 17, section 13.

R. To the 2nd: Even after mutual aggression and conflict, when some have already fallen on the side of him who wages a just war, condign satisfaction must be accepted and the war interrupted, if that is offered by the adversary Prince; if not from the rigor of justice, at least for the most part from charity, provided that the other party is willing to compensate all expenses already made, and it is not necessary for the public good that his insolence be beaten back. The 1st reason is that then war already ceases to be necessary for the end. The 2nd reason is that, since in a vindicative war, after many have already fallen, it is almost impossible to give condign satisfaction, the offended Prince, from a war actually begun, is not bound from justice, but rather from charity alone, to desist and to accept satisfaction. Laymann l. 2, tr. 3, c. 12, n. 5; L. 405.

R. To the 3rd: In offensive war, after the thing owed has been recovered and every indemnity, or after the injury has been sufficiently vindicated, the victor is bound to accept peace furnished with just conditions. The same is true of the victor in defensive war, after he has sufficiently vindicated the injury inflicted on him. The reason is that excess would be against the right of vindicative justice, indeed even of commutative justice. Besides, the end of war is peace and security. Therefore, once these have been sufficiently obtained, war, as an atrocious means, must be desisted from. Moreover also the conquered, per accidens, is often bound to accept peace, lest he expose himself and his subjects to greater danger, misfortune, or intolerable inconvenience. Struggl 44; Cajetan, Summ. v. Bellum. A nation which justly wages war can occupy the goods of enemies as much as is necessary for compensation of the damages which it has suffered, for payment of the expenses of war, and for just vengeance of the injury.

408. Questions. - Q. 1. Whether it is lawful to wage war with probability of one's own right?

Resp. It is disputed. But the negative part is far more probable, at least intrinsically and practically. The reason is: 1. because a possessor in good faith cannot be despoiled of the thing possessed unless it is clear that he unjustly retains it; 2. because for placing the cause of most grave evils, such as slaughters, injustices, corruptions of morals, and other things of this sort which ordinarily follow war, moral certitude of one's own right seems to be required. - St. Alphonsus, n. 404; Tamburini; Billuart, against several, of whom some think that only greater probability suffices, but others that equal probability does.

Q. 2. Whether soldiers can wage war with doubt concerning the justice of the war?

Resp. 1. If there is question of a soldier who is a subject, he is bound to obey where the war is not evidently unjust, because it does not pertain to him to examine the reasons of Superiors ¹.

¹ What some have said, that the authority of the prince suffices for a probable judgment of the justice of a war, Lugo rightly observes (De Iust., disp. 18, n. 21) is not always and universally true. For when (he says) I know from elsewhere that the prince commonly commands shameful things at his pleasure, and... without any attention at all to what is lawful, how can I believe from the mere command of the prince that what he commands is just? And a little after, as regards princes whom we know to be destitute of the Christian faith: Since the soldier cannot prudently trust to their conscience, inasmuch as they care little about the justice of war, he ought attentively to consider and examine the justice and the cause of the war, so that he may be able to form that probable judgment.

2. If there is question of a soldier hired before the war was declared, he can obey; for he is hired for this. Whence he must conduct himself almost as if he were a subject.

3. If there is question of a soldier not yet hired, he is bound to inquire concerning the justice of the war, nor in doubt concerning the justice can he hire himself out. The reason is that no one can cooperate toward despoiling another of a thing which he possesses, unless he is certain that it is possessed by him unjustly. - St. Alphonsus, n. 408.

Q. 3. Whether it is lawful for Catholic Princes in a just war to call heretics and infidels to their aid?

Resp. It is affirmed per se, at least speaking speculatively, provided scandal and danger of the Faith are absent. But, says St. Alphonsus, n. 406, for the most part by accident it is illicit on account of damages threatening Religion.

Q. 4. Whether guilty or innocent persons can be killed by the victor?

Resp. 1. Guilty persons can sometimes be killed, or soldiers who have fought, if this is necessary for establishing peace and security or vindicating injury, unless they have surrendered themselves with an agreement that life be preserved. But this is altogether alien to the customs of our time.

2. But innocents, that is, women, the old, pilgrims, Clerics, Religious, etc., cannot be killed directly unless it is clear that they were associates in the war. Yet they can be killed indirectly, while the battle is not yet completed, if they are mixed with the guilty, so that, with these preserved, the remaining crowd of the guilty which must be destroyed cannot be killed. - St. Alphonsus, n. 409.

346. Principle: In order that war may be undertaken legitimately, a threefold condition is required and suffices: the authority of the supreme civil power, a just cause, and a right intention.²

² Thus St. Thomas, 2. 2., q. 40, a. 1.

1. There is required: (A) Supreme authority; for it does not belong to a private person to move war, since he can pursue his right before tribunals, even when injury has been inflicted by a foreigner; but only to him to whom the care of the commonwealth has been committed: for there is question of a matter pertaining to the good of the whole society; and therefore, just as it belongs to supreme authority to use the sword against evildoers who disturb the social order from within, so it belongs to it to protect the commonwealth from exterior enemies by the military sword. But this supreme authority sometimes resides in princes, sometimes in presidents of the commonwealth, with the assent of the Legislative Assembly;³ in whatever hypothesis, it is licit to declare war only after mature deliberation, and after upright men and experts in international law have been consulted: for there is question of a matter of most grave moment.

³ Thus in France: "The President of the Republic cannot declare war without the prior assent of the two Chambers." (Loi constit. of July 16, 1875, a. 9.)

347. (B) A just cause; and this must be proportionately grave; now since in wars, especially modern wars, many men are killed and innumerable resources are destroyed, war can be declared only from a most grave cause; indeed it is required that it be necessary, namely one for which no peaceful means can provide a remedy. Therefore, before recourse is had to arms, a way must solicitously be sought by which the dispute that has arisen can be settled peacefully, whether by sending ambassadors, or by having recourse to mediators or arbiters,¹ as often as this can be done without dishonor.

¹ At The Hague (La Haye) an international tribunal was instituted in the year 1899, for peacefully settling disputes which arise between various Nations: it is certainly to be wished that recourse be had to this tribunal for the most part, rather than to arms; cf. De Martens, La Conference de la Paix a la Haye, Paris, 1901; H. Bonfils, op. cit., p. 527. - The same author shows that arbitration was already in use, and indeed with a happy outcome, p. 533-542.

348. Among just causes are numbered: the unjust invasion or detention of some province by enemies; grave injuries inflicted either upon the nation itself, or upon ambassadors, or upon citizens, which a foreign nation obstinately refuses to repair; violation of a treaty or pact, with great detriment to the commonwealth; violation of neutrality, as they say; the necessity of bringing aid to another people unjustly oppressed. - But diversity of religion or the desire of converting infidels to the faith by no means suffices: for true religion is propagated not by arms, but by prayers and preaching.² - Nor the sole enlargement of empire: otherwise there would be an equally just cause on each side of those waging war, and the right of the stronger, not the stronger right, would prevail everywhere. - Nor the singular progress of some nation, which so increases in power that it now surpasses neighboring nations formerly equal. - Nor one's own glory or the private good of the Prince or of his family: for private good ought to yield to public good.

² Vitoria proves this at length, op. cit., De Indis, p. 305-409.

349. Yet here it can be asked whether a cultivated nation can invade the territory of a barbarous nation, in order to impart to it the benefit of modern civilization. And here indeed a distinction is needed: (a) if a certain nation has more citizens than it can nourish, and on the other hand there are regions by no means or little cultivated, because of the scarcity of inhabitants or their ignorance or sloth, it is not unjust by peaceful means to occupy almost empty territories, while giving fair compensation to the natives; but if they do not wish to accept this and wish to repel the occupiers by force, those who use moderate force to retain the territory which they need for procuring the necessities of life for themselves cannot be reproved for injustice; for the earth was entrusted primarily to our first parents for assisting human necessities. (b) But if, under the pretext of imparting a higher civilization, regions already sufficiently cultivated by their inhabitants are invaded by force and arms, the aggression seems to be unjust: for civilization ought to be propagated not by arms, but by persuasion, industry, and commerce; otherwise nations which consider themselves more cultivated will soon invade and oppress others.

350. (C) Right intention, by which, namely, it is intended that the good of society be promoted or evil warded off; therefore intentions which are opposed to Christian charity or justice must carefully be removed, such as desire of harming, cruelty of taking revenge, lust for dominating, an implacable mind. Therefore occasions of war are not to be sought on account of the great profit hoped for from it: "For it is of the utmost savagery," says Vitoria, op. cit., p. 466, "to seek causes, and to rejoice that there are causes for killing and destroying men whom God created, and for whom Christ died; but one ought to come to the necessity of war compelled and unwilling." Indeed equity counsels that Rulers desist from that which they foresee will be an occasion of war; for the occasion of such grave evils must carefully be removed.

351. 2. It suffices, or, with all the conditions set forth above having been posited, war is licit. For often war is the only means by which some nation can efficaciously protect its own existence or rights of great moment; for there is no tribunal on earth, even today, which can compel nations dissenting among themselves to settle a dispute peacefully. Now a nation can defend itself and its rights, when they are of most grave moment, against unjust aggressors; for if private persons can do this, in the case of actual aggression, a fortiori a nation can, which has the same and more powerful rights, insofar as it enjoys public authority; but if an enemy is not actually attacking, but does not wish to repair a grave injury inflicted, rights can be vindicated by force, since there is no tribunal before which they can peacefully be sought again; otherwise the unjust and violent would soon oppress the honest and meek. Therefore war can be licit.

Nevertheless it is to be wished that soon an international tribunal be instituted before which nations dissenting about a matter of grave moment are bound to present themselves; and indeed it is equitable that the president of this tribunal be the Roman Pontiff, vicar of Him who is deservedly called the Prince of peace.

352. Corollaries. (a) For declaring offensive war a probable motive does not suffice, but a morally certain cause is required; thus commonly. For since here there is question not only of one's own rights, but of the rights of others, and on the other hand so many and so great evils follow from war, it is not licit to use probable opinions in a matter of such moment. Hence it is necessary to weigh the causes of war with the greatest prudence, to hear the reasons of the adversaries, if they wish to discuss from fairness and goodness, and to seek the counsel of upright and wise men, who may speak with liberty, without anger and hatred. When this has been done, if doubt remains, recourse must be had to arbiters; if the other party rejects this recourse, a legitimate cause for declaring war is now had.

(b) Even when a just cause certainly exists, justice demands that, before war is begun, reparation be sought from the adverse party; and if suitable reparation is offered, one must abstain from war. This is clear from what was said above; for war must be warded off by all legitimate and honorable means.

1. LAWFULNESS OF WAR.—What self-defense is for the individual, that war (bellum) is for society or the State, namely, the act of warding off unjust attacks or of asserting important rights by force of arms.¹

¹ J. P. Gury, Comp. Theol. Mor., Vol. I, n. 418: “War is the struggle of a multitude against an external multitude for the purpose of defending or vindicating the commonwealth. Hence it differs: 1. From a brawl, which is a fight of a few against a few; 2. From sedition, which is a disturbance or conflict of a multitude against political society.”

The purpose of war, therefore, is to protect the material, moral, and spiritual possessions of a nation, such as religion, liberty, independence, honor, good name, its right and power to conclude treaties, etc. When war is waged within the limits of a just self-defense, that is, after all other means to preserve the peace² (such as diplo- matic negotiations, arbitration, reprisals, blockade, etc.) have proved ineffective, and the sword has become the final and inevitable arbiter, and if the moderamen inculpatae tutelae is duly observed, war is not only morally lawful, but may be a social duty, and participation therein may become a highly meritorious act.³

² Cfr. Deut. XX, 10.—Cfr. J. P. Gury, Comp. Theol. Mor., Vol. I, n. 419: “For a just and lawful war the following are required: 1. Public authority, that is, supreme authority acknowledging no other superior in civil matters. The reason is that where a higher authority exists, it must judge the dispute; 2. A just and grave cause which outweighs the disadvantages that will follow from the war, e. g., a kingdom or province to be recovered, or a grave injury done to the commonwealth to be repelled, or a rebellion of subjects to be suppressed, etc.; 3. The proper manner of waging war, namely, that before war adequate satisfaction be demanded from the opposing party, and if it is offered, it must be accepted as a matter of justice; for where war ceases to be necessary, it also ceases to be just.” N. 424: “A prince, once the justice of a war has been recognized, must present it to the opposing party and cannot begin the war, if adequate satisfaction is offered to him; indeed, even a war already begun he is bound to abandon when adequate satisfaction is offered, if not from the rigor of justice, at least generally from charity, provided the other party is willing to compensate all expenses already incurred and it is not necessary for the public good that it be repelled.”

³ Cfr. Judg. XI, 27.—Gury, op. cit., Vol. I, n. 419: “War is of itself permissible either to repel an injury or to vindicate one's right. The reason is that every society independent of another society must have a means of protecting itself against injury and vindicating its right. Sometimes, however, no other means is available for obtaining this end except war. For since higher authorities to whom nations or princes might have recourse are lacking, they may wage war to obtain satisfaction from another society.”

God repeatedly commanded His Chosen People to wage war against their enemies and lent them His special assistance and co-operation.⁴ St. John baptized soldiers, but neither he nor Christ Himself required of them that they renounce their profession;⁵ all they asked of them was, to “do violence to no man,” i. e. abstain from injustice.⁶ St. Paul says that the civil authority, as the representative of God, has the right of wielding the sword in order to protect law and order against domestic evil-doers and foreign enemies.⁷

⁴ Ex. XIV, 13 sq.; Deut. I, 29 sq.; III, 21 sqq.—Cfr. F. Schwally, Semitische Kriegsaltertümer, Leipzig 1901, 1. Heft, pp. 3 sqq.

⁵ Cfr. St. Augustine, Contra Faustum Manich., l. XXII, c. 74: “Otherwise John, when soldiers came to him to be baptized, saying, ‘And what shall we do?’ would have answered them: ‘Cast away your arms, abandon this military service, strike no one, wound no one, lay no one low.’ But because he knew that when they did these things as soldiers they were not murderers but ministers of the law, and not avengers of their own injuries but defenders of the public safety, he answered them: ‘Do violence to no one,’” etc. (Migne, P. L., XLII, 447.) IDEM, Epist. 189 (al. 205), n. 4: “Do not think that no one who serves under arms in war can please God. Holy David was among them, to whom the Lord bore such great testimony; among them also were very many righteous men of that time. . . . John certainly did not forbid those soldiers to serve under arms whom he instructed that their own pay ought to suffice.” (P. L., XXXIII, 855).

⁶ Luke III, 14; Acts X, 1 sqq.

⁷ Rom. XIII, 1–5; cfr. John XIX, 10 sqq.

If some of the Church Fathers objected to Christians serving as soldiers, they did so for the reason that the life of a soldier in their days was full of danger to faith and morals, and that the ancient State, with its emperor-worship, was essentially pagan. There is sufficient evidence to show that the early Christians acknowledged legitimate warfare as morally licit.⁸ The canonical law exempting clerics from military service was based upon the supernatural and pacific character of their office.⁹ The Church not only admits that war may be just, but she admonishes her children to fight for their highest and most sacred possessions.¹⁰

⁸ Cfr. Ch. Lupus, De Antiqua Disciplina Christianae Militiae, XI (Opera Omnia, Venice ed., 1729), pp. 94 sqq.—Hefele, Beiträge zur Kirchengeschichte, Vol. I, pp. 20 sqq.—K. Künstle, Zwei Dokumente zur altchristlichen Militärseelsorge, Mayence 1900, pp. 3 sqq.—A. Bigelmair, Die Beteiligung der Christen am öffentlichen Leben, Munich, 1902.—A. Harnack, Militia Christi, Tübingen 1905, pp. 46 sqq.

⁹ Syllabus Errorum, n. 32 (Denzinger-Bannwart, n. 1732).—C. Richert, Die Anfänge der Irregularitäten, Freiburg 1901, pp. 114 sqq.

¹⁰ Errores M. Lutheri damn. a Leone X, n. 34 (Denzinger-Bannwart, n. 774).

2. GUIDING PRINCIPLES.—a) Every just war is by its very definition defensive (bellum defensivum), because war is permitted only as an extreme means of self-help or to protect a na- tion's legitimate rights or interests. It does not, however, follow that when a State is unjustly menaced in its vital interests,—be they material, moral, or spiritual,—it is not permitted to make use of its right per modum praeventionis, i. e., to forestall a threatening attack, for instance, by occupying foreign territory, compelling enemy troops to lay down their arms, cutting off their supplies, destroying fortifications, and so forth. Such a war, though seemingly offensive, would in reality be defensive, for the justice of a war depends not upon its physical, but upon its moral authorship. It is also licit and therefore just, nay, it may even be a duty for a nation to assist another, especially an allied nation, in warding off an unjust attack.

The socalled principle of non-intervention, that is, non-interference of a State in hostilities between other States, unless its own territory or rights are attacked, may be justifiable from a purely political point of view, but not morally,¹¹ because if a nation unjustly attacks another, all others are threatened in their very existence, and under the law of nations every State is in duty bound to protect right and justice. Intervention, if exercised in accordance with the principles of morality, constitutes an effective support of international law and order. For the rest, its exercise in most cases will not entail war, but merely lead to diplomatic negotiations.

¹¹ Syllabus Errorum, n. 62: “The principle which they call that of non-intervention must be proclaimed and observed.” (Denzinger-Bannwart, n. 1762).—Cfr. M. Pachtler, S. J., “Das Prinzip der Nichtintervention,” in the Stimmen aus Maria-Laach, Vol. I (1871), pp. 107 sqq., 196 sqq.—A. Stöckl, Das Christentum, Vol. II, pp. 353 sqq.; Vol. III, pp. 22 sqq.

b) The moderamen inculpatae tutelae must be kept inviolate even in a just war. Consequently, war may not be continued longer than is necessary to accomplish its object, that is, until full satisfaction or reparation has been obtained and peace secured. Disregard of this principle would be a violation of the moral law of nature and involve the duty of restitution. To undertake or continue a war solely for the acquisition of territory or as a preventive of internal dissensions would be positively criminal.¹²

¹² Osee V, 13.—St. Augustine, De Civ. Dei, l. IV, c. 6: “To bring wars upon neighboring peoples and thence proceed against others, and from mere lust for dominion to crush and subjugate peoples who do not trouble one—what else should this be called but grand robbery?” (Migne, P. L., XLI, 116 sq.).—Contra Faustum Manich., l. XXII, c. 74: “What is blamed in war? Is it that those who will die sometime die, so that those who will live in peace may be subdued? To censure this belongs to the timid, not to the religious. The desire to harm, the cruelty of vengeance, an unpacified and implacable spirit, the savagery of rebellion, the lust for domination, and anything similar—these are the things rightly blamed in wars.” (P. L., XLII, 447).

Secondly, not all is fair in war. Absolutely damnable and illicit means of warfare are: lying, perjury, the intentional dissemination of false reports, e. g., of faked victories. Among the licit means are: espionage, stratagems, ambuscades, etc.; these are allowed because they are not based on lies pure and simple, but merely furnish the enemy an occasion for drawing false conclusions.

Third, the means employed in warfare must not be more cruel than is necessary for the successful termination of the bloody struggle.

It goes without saying that the direct slaying of innocent and unarmed persons, such as women, children, and old men, or the dishonoring of women can never be justified under any pretext.¹³

¹³ St. Thomas, Summa Theologica, 2a 2ae, qu. 40, art. 3: “It is permissible in war to prepare ambushes and employ stratagems, so that enemies may be deceived by ruses and cast into various dangers. For these things are not reckoned lies, because the adversaries are deceived by their own fault, since such means are customarily employed in war; thus it is permissible to feign flight, to use the enemy's standards, etc. But those deceptions are illicit which cannot be guarded against by any prudence, e. g., to poison wells and springs, etc. For these things, in common judgment, conflict with the laws of war.”

Fourth, the right to kill the enemy or damage his property belongs to individual soldiers or single divisions of an army only in so far as they have been authorized to proceed by legitimate authority. Therefore, if an army, or any single division thereof, marches through enemy territory plundering and robbing the populace, without the express or at least implicit authorization of its commander, it is no better than a band of marauders and its members are bound to restitution. Officers bearing a flag of truce are inviolable.

c) In addition to these general principles, derived from the moral law of nature, the so-called international law has laid down others which deserve mention. One of these is that the laws of war apply only to active combatants, i. e., persons actually wielding or entitled to wield arms. Hence it is not allowed to kill a disarmed or captured soldier. Non-combatants engaged in the service of an army, such as chaplains, physicians, nurses, etc., may not be killed, but they may be made captives. Prisoners of war should be treated humanely, but not better than the soldiers of one's own army, lest cowardly members of the latter be tempted to surrender. Weapons which render war more cruel without hastening the decision are forbidden. To this class belong explosive hand guns, poisoned arrows, poison substances, the poisoning of wells, etc. Those living peaceably in enemy territory should not be treated harshly and their property should be spared unless it is needed to enable the invading army to live. The retention of hostages, the devastation of the country, the destruction of crops, the burning of dwelling houses and other necessities of life are permissible only in exceptional cases, when necessary for the carrying out of an important operation or to overcome the hostile attitude of the populace. Wounded soldiers who are no longer able to fight should be protected against attacks upon their person.¹⁴

¹⁴ Of the barbarities of war Fr. Ross justly says: “Once the dogs of war are let loose, it is difficult to keep them within the bounds of civilized Christian custom. The records of Sherman's march to the sea, of English conduct in the Sepoy rebellion, of our water cure and other tortures in the Philippines, of the international intervention in China during the Boxer rebellion, do not make us very proud of humanity. There is an old saying, ‘Scratch an Englishman and you find a barbarian,’ and this is equally true of the Germans, French, Italians, and Americans.” (Christian Ethics, pp. 426 sq.).

Under the Geneva Convention, of August 22, 1864, all military hospitals and ambulances with their attendants, physicians and nurses, when carrying the Red Cross, as well as all buildings containing wounded soldiers who display the Red Cross flag, are neutral and must not be attacked or molested. Citizens who receive wounded war victims into their houses shall be excused from quartering troops and also, partially, from paying war contributions.¹⁵

¹⁵ H. Dunant, Un Souvenir de Solférino, Geneva 1862; 2nd ed., Paris 1871; C. Lueder, Die Genfer Konvention, Erlangen 1876; H. Lammasch, Die Fortbildung des Völkerrechts durch die Haager Konferenz, Stuttgart and Vienna 1900; A. Zorn, Das Kriegsrecht zu Lande in seiner neuesten Gestaltung, Berlin 1906; J. E. Ross, C.S.P., Christian Ethics, pp. 430 sq.; Lawrence, Principles of International Law, Boston 1909.

The use of savages or convicted criminals is morally objectionable, because they are apt to disregard the laws of war. Attempts to induce enemy soldiers to break their oath of loyalty or to rebel against their superiors are likewise inadmissible.

d) Voluntary participation in a war which one regards as unjust is sinful. Since, however, the individual citizen is rarely in a position to form a reliable judgment concerning the justice or injustice of a war, and since, moreover, a soldier employed or drafted by the government (miles subditus) has not the right to question the justice of an international quarrel, he must obey his supe- rior officers even though he doubts the justice of the cause. But he is never permitted to co-operate in manifest injustice or criminal acts of violence, e. g., the maltreatment of peaceful non-combatants or the killing of soldiers who have unconditionally surrendered. Mercenaries (milites conducti), who have been hired before the outbreak of a war, may take part therein even if they doubt its justice. The case is different with those who volunteer their services after the war has started (milites nondum conducti); if they are in doubt as to the justice of the cause in which they intend to enlist, they are in duty bound to obtain certainty, for no man is permitted to co-operate in an unjust cause.¹⁶

¹⁶ Rom. XIII, 1 sqq.—St. Augustine, Contra Faust. Manich., l. XXII, c. 74: “And for this purpose taxes are paid (Mt. 22, 21), so that, because of wars, pay may necessarily be furnished to the soldier.” (Migne, P. L., XLII, 447).—IDEM, ibid., c. 75: “When a just man happens to serve as a soldier under a king who is even a sacrilegious man, he can rightly wage war at that king's command while preserving the order of civic peace: either it is certain that what is commanded of him is not contrary to God's precept, or it is not certain whether it is; so that perhaps the injustice of commanding makes the king guilty, while the order of serving shows the soldier innocent.” (P. L., XLII, 448).—J. P. Gury, Comp. Theol. Mor., Vol. I, n. 421: “It is asked whether soldiers may wage war while in doubt about the justice of the war. The answer is: 1. If the question concerns a subject soldier, he is bound to obey where the war is not evidently unjust, because it does not belong to him to examine the reasons of his superiors. 2. If the question concerns a soldier hired before war was declared, he may obey; for he is hired for this, and therefore must conduct himself almost as if he were a subject. 3. If the question concerns a soldier not yet hired, he is bound to inquire into the justice of the war and cannot place himself in doubt about its justice. The reason is that no one can co-operate in despoiling another of a thing which he possesses unless he is certain that it is possessed by him unjustly.”

The causes of war are as a rule hidden to the ordinary citizen, nay ofttimes even to the better informed and more sensitive organs of public opinion. Ordinarily, the private citizen may and should presume that his country is right. The question how far his duty of obedience goes, and for what acts of violence he may allow himself to be used, are answered by the ius belli, but its provisions are of little practical importance, because in case of doubt every citizen will naturally submit his subjective opinion to the supposedly more enlightened judgment of the authorities.¹⁷

¹⁷ Cfr. F. X. Linsenmann, Lehrbuch der Moraltheologie, pp. 469 sqq.; Ross, Christian Ethics, p. 440.

3. MORAL ESTIMATE OF WAR.—a) Just war is not only permissible as an act of self-defense, but it may be useful for the punishment of injustice, the restoration of law and order, and as an instrument of correction in the hands of God.¹⁸

¹⁸ Judg. II, 20 sqq.; III, 1 sqq.; Is. X, 5 sqq.; 2 Macch. V, 17 sq.

Nor can it be denied that a number of noble virtues, e. g., loyalty, courage, self-sacrifice, fidelity to duty, are developed by and in war, and that bloody conflicts with other nations often strengthen the moral and religious fibre of a nation and promote patriotism. A war waged against savage tribes, may, moreover, serve the purpose of genuine culture and the legitimate needs of colonization.¹⁹

¹⁹ Cfr. Horace, Epist., l. II, 1, 156 sq.: “Graecia capta ferum victorem cepit et artes intulit agresti Latio.”

b) On the other hand, though a just war may prove a moral blessing for a nation or for humanity at large, even the justest war is in- variably accompanied by so many horrors and barbarities, and entails so much material and moral destruction that it must be regarded as an evil and a terrible scourge. Though the Bible acknowledges the legitimacy of war and of the military profession, there are many passages in both Testaments which point to lasting peace as the final goal for the human race to strive after.²⁰ War does not fit into the ideal picture of international intercourse. Its existence and relative necessity is merely a sad proof how little even Christian nations are actuated by the spirit of charity, peace, and justice. The highest good of the State, the ideal political condition of a people, is that “rest from all enemies round about” described in Deuteronomy,²¹ and permanent peace must be the first and foremost aim of every real statesman. Kant's idea of a universal peace²² has no prospect of realization because it is based for the most part upon purely worldly interests or upon so-called humanitarian or philanthropic considerations and motives, which are at bottom utopian, instead of seeking the peace of Christ which the world cannot give.²³ Nevertheless every attempt to settle international difficulties and quarrels by means of arbitration should be hailed with joy. An international tribunal of arbitration might not prevent war entirely, but it would postpone the outbreak of hostilities and thus give reason instead of passion an opportunity to speak the last word. Even though war were abolished, it would still be “sweet and meet to die for one's fatherland,”²⁴ and every citizen would have sufficient opportunities to prove his patriotism by faithfully performing his duties towards God and the legitimate civil authorities.

²⁰ Ps. 67, 31; Is. II, 4; Mich. IV, 1 sqq.; Matt. XXIV, 6; Mark XIII, 7; Luke XXI, 9 sq.

²¹ Deut. XII, 9 sq.; XXV, 19. St. Augustine, Epist., 189 (al. 205), n. 6: “The will ought to have peace, necessity war, so that God may free us from necessity and preserve us in peace. For peace is not sought so that war may be stirred up, but war is waged so that peace may be acquired.” (Migne, P. L., XXXIII, 856).—IDEM, Epist., 229 (al. 262), n. 2: “Great indeed are not only the bravest warriors, and they have their own glory, but also—and this is a truer kind of praise—the most faithful warriors, by whose labors and dangers, with the aid of God who protects and helps, the untamed enemy is conquered and tranquility is procured for the commonwealth and the pacified provinces. But it is of greater glory to kill wars themselves with a word than men with the sword, and to acquire or obtain peace by peace, not by war. For even those who fight, if they are good, undoubtedly seek peace, but nevertheless through blood.” (P. L., XXXIII, 1020).

²² I. Kant, Zum ewigen Frieden, Königsberg 1795 (edited by K. Kehrbach, Leipsic 1881).—Cfr. F. von Holtzendorff, Die Idee des ewigen Völkerfriedens, Berlin 1882.—L. Stein, Das Ideal des ewigen Friedens, Berlin 1896.—Ch. Richet, Les Guerres et la Paix, Paris 1901. K. F. Küster, De Treuga et Pace Dei, Cologne, 1902.—P. Meyer, Die Idee des ewigen Friedens bei Kants Zeitgenossen, Berlin 1903.—K. Geissler, Der Krieg und die sozialen Sünden, Jena 1905.

²³ John XIV, 27; cfr. Judith XVI, 3: “The Lord putteth an end to wars.”—St. Leo the Great, Serm., 82 (al. 80), c. 1: “Although [the city of Rome], enlarged by many victories, extended the jurisdiction of your empire by land and sea, nevertheless what military toil subjected to you is less than what Christian peace subjected to you.” (Migne, P. L., LIV, 423).

²⁴ Horace, Carm., III, 2, 18: “Dulce et decorum est pro patria mori.”—Cfr. Homer, Ilias, XII, 243.

In striving for international peace it is well for us to realize that there are many strong “interests” that must be vigorously opposed. First of all come the war traders. “Those who en- gage in the sale of materials of war know that it is to their advantage to foster the military spirit. The more one nation spends on preparation, the more the others are forced to spend. It is an endless chain. A few individuals are enriched, but the vast majority suffer from such enormous expenditure in unproductive ways. Perhaps the problem could be partly solved by the various governments taking over the munition factories. But the solution is problematical and at best would be merely partial. For only a completely socialized State could take over all the industries directly and indirectly depending upon war. A hardly less important expression of commercialism versus peace is found in yellow journalism. Newspapers recognize that in order to sell large editions they must exaggerate. As a consequence they are absolutely conscienceless in dressing up reports of differences between nations. Again, there arises in the popular mind induced by this irresponsible journalism a certain spread-eagleism, an attitude that sees no fault in one's own nation, but faults innumerable in others—a loud-mouthed patriotism [rectius: jingoism] that is ready to call every man a traitor who happens to advocate peaceful methods. . . . This evil of yellow journalism tends to grow worse and worse. New forms of exaggeration, new appeals to this false patri- otism must be constantly devised; for as one form grows stale, it becomes useless from a journalistic standpoint. And so one fosters the other. The public, weary of the drab dullness of everyday life, demands of the newspapers a certain amount of sensationalism and grows more rampant the more it gets.”²⁵

²⁵ J. E. Ross, Christian Ethics, pp. 436 sqq.

READINGS.—St. Augustine, Contra Faust. Manich., l. XXII, c. 74–78.—IDEM, Epist., 189 (al. 205), n. 4 to 6.—St. Thomas, Summa Theologica, 2a 2ae, qu. 40 (Rickaby, Aquinas Ethicus, I, 407 sqq.).—St. Alphonsus, Theol. Mor., l. III, n. 402–411 (ed. Gaudé, I, 659 sqq.).—H. Grotius, De Iure Belli et Pacis, Amsterdam 1712.—J. Walter, Naturrecht und Politik, pp. 462 sqq.—A. Stöckl, Das Christentum, Vol. III, pp. 417 sqq.—F. X. Linsenmann, Lehrbuch der Moraltheologie, pp. 468 sqq.—V. Cathrein, S.J., Moralphilosophie, Vol. II, 5th ed., pp. 741 sqq.—F. Kattenbusch, Das sittliche Recht des Krieges, Giessen 1906.—M. Cronin, The Science of Ethics, Vol. II, pp. 663 sqq.—Jos. Rickaby, S.J., Moral Philosophy, pp. 191 sqq.—Chs. Macksey, S.J., art. “War” in the Catholic Encyclopedia, Vol. XV, pp. 546–550.

130. It is explained. That war is sometimes licit is admitted by all (except the Manichaeans, Quakers, and a few others). For war is sometimes the only means for some people to vindicate its own rights, indeed to defend its own existence. Besides, if war were something illicit, God Himself would not often have commanded wars in the Old Testament. - But for licitly beginning war, according to St. Thomas¹⁵² and other authors, three conditions are required:

a) The authority of the supreme civil power, because a private person can pursue his right in the judgment of a superior judge, and therefore does not need war in his own cause; nor does it belong to him directly to procure the common good. - "Likewise also to call together a multitude, which must be done in wars, does not belong to a private person. But since the care of the republic has been entrusted to princes, it belongs to them to guard the republic of the city or kingdom or province subject to them. And just as they licitly defend it with the material sword against interior disturbances when they punish malefactors, ... so also it belongs to them to guard the republic with the warlike sword against exterior enemies."¹⁵³ Now this supreme authority of declaring war sometimes resides in the prince alone, sometimes in the prince or president with the assent of the legislative assembly.

b) A just cause, and that most grave, is required, according to this: "To wage war is not of will, but of necessity."¹⁵⁴ The reason is that in war the greatest material damages arise, a great number of men is killed, and often even the innocent must suffer the harshest cruelties. Therefore before war is begun, one must strive with all strength that peace be preserved and the causes provoking war be eliminated. But if all efforts have been vain, it is licit to begin war. For defensive war a most urgent cause is not required; it is enough that the prince offer fitting satisfaction for the complaints of the other prince; if this satisfaction is spurned, defensive war is licit. For beginning offensive war there is not sufficient a) the desire of converting infidels to the true faith, nor b) the enlargement of one's own empire, nor c) one's own glory, etc. "There is one and only just cause of making war: an injury received." Thus rightly says Francis de Victoria;¹⁵⁵ hence, for example, the following causes suffice: recovery of a province unjustly held by another, vindication of a grave insult brought upon the republic or prince, vengeance upon a nation which has unjustly violated a treaty entered into, etc. In present times the question can arise whether a civilized nation can make war upon pagan tribes altogether lacking culture in order to found colonies? - If those pagans are treated kindly and fitting compensation for vacant or lost land is offered to them, which they refuse to accept, war does not seem to be so illicit. The reason is that otherwise those lands would remain uncultivated, and the inhabitants would lack the great benefit of moral and religious culture. Therefore they seem to be irrationally unwilling that colonies be founded in their regions so sparsely inhabited. Thus speaking theoretically; for in fact European nations have often founded colonies in foreign regions with the greatest injustice.

c) A right intention is necessary, by which namely it is intended that good be promoted or that evil be avoided, and by which an act of true vindicative justice is exercised.¹⁵⁶ On this matter St. Augustine writes: "The desire of harming, cruelty of avenging, an unpacified and implacable spirit, fierceness of rebellion, lust of domination, and whatever things are similar: these are the things which are rightly blamed in wars";¹⁵⁷ and: "War is waged that peace may be acquired. Therefore be peaceful by warring, so that by conquering you may lead those whom you attack to the utility of peace."¹⁵⁸

If these three conditions are present, war may be licitly begun. Nevertheless it is often much better, in discords arisen among diverse nations, to have recourse to the so-called international tribunals of peace; because it is almost always better to suffer some material damage than to prepare the scourge of war for oneself or others. Hence not undeservedly in the Litany of All Saints there is the deprecation: "From pestilence, famine, and war, deliver us, O Lord!" - In our times and in our regions it no longer belongs to common soldiers or inferior officers to judge concerning the liceity or illicitness of war; for it is altogether impossible for a private man to know all the motives which induced the so-called national Diplomacy to begin war. Besides, soldiers now are not free to fight or not to fight; on the contrary they would be punished with death itself if they refused to fight. Therefore in practice any soldier and subordinate officer can suspend his judgment concerning the justice or injustice of war, and if he is compelled to war, can fight with a safe conscience. But in those regions where soldiers are still freely hired and can freely desert military service, the matter stands otherwise. For then any soldier, before he undertakes military service, must have moral certitude concerning the justice of the fight and war; for it is a matter of the gravest damages to be inflicted upon the neighbor and of the most imminent danger to one's own life.

Once war has been begun, the statutes of the law of nations must be observed. But what things in particular are permitted or prohibited by the law of nations according to modern practice sometimes does not so appear. This must be held as a fundamental principle: War is not waged against private citizens, but against the nation as a public person, as has already been said above, n. 47. It is lawful to employ all those things which are necessary for breaking the strength of the enemy and which are not intrinsically illicit. Wherefore it is lawful to besiege fortified citadels and deprive them of all provisions, so that they may surrender themselves more quickly; likewise to fire cannons (commonly, Kanonen) against them, even with danger (but not with direct intention) of killing innocent persons, destroying churches, monasteries, etc.¹⁵⁹ "But since the expenses of war can be exacted from the enemy, the victor, when cities and villages have been captured, can impose taxes, provided they are proportionate to the resources of the inhabitants; but to give a captured city as booty to the army is not lawful today."¹⁶⁰ Also licit are the so-called Repressalia, provided they have been justly determined by the prince for repelling an injury inflicted by the enemy. - Soldiers sin gravely if in a just war they desert military service or flee over to the enemy. The reason is that they sin gravely against obedience, and because they expose themselves to the greatest danger of death; for, if they shall have been captured, they are killed without mercy.

When the conquered enemies ask for peace, the victor must use the victory obtained moderately. Therefore let the conditions of peace not be very harsh. But it belongs to no private man to judge concerning the equity of such compensations and conditions.

Among the ancient authors besides St. Thomas, especially Francis de Victoria wrote best concerning the right of war.¹⁶¹

Scholion. On private men during war. Today it is most strictly prohibited that private men involve themselves during war in warlike affairs or take up arms. Transgressors of this statute are certainly justly punished with the penalty of death. Therefore during war especially clerics should beware lest in any way by words or deeds they participate in war.

¹⁵² S. theol. 2, 2, q. 40, a. 1.

¹⁵³ S. theol. 2, 2, q. 40, a. 1.

¹⁵⁴ c. 1, C. 23, q. 2.

¹⁵⁵ Relectiones de iure belli n. 13. In a similar way St. Augustine says: "Just wars are accustomed to be defined as those which avenge injuries" (c. 2, C. 23, q. 1).

¹⁵⁶ Cf. Cajetan, Summula, s.v. "Bellum."

¹⁵⁷ Contra Faustum l. 22, c. 74; cf. c. 4, C. 23, q. 1.

¹⁵⁸ Ep. 149 to Boniface; cf. c. 3, C. 23, q. 1.

¹⁵⁹ Cf. St. Alphonsus, Theol. mor. l. 3, n. 410.

¹⁶⁰ Thus rightly Tanquerey, Synopsis Theol. mor. de iustitia n. 355.

¹⁶¹ Relectiones theologicae lect. 6.

273. Principle I. War can be undertaken justly; for this a threefold condition is required: the authority of the supreme civil power, a just cause, and right intention.¹

¹ On war, besides St. Thomas in the cited place with the commentary of Cajetan and Bannez, one may consult Fr. de Victoria, Relectiones morales, l. IV, de iure belli; — Suarez, De Charitate, on II-II, q. 40; — Grotius, De Iure belli ac pacis; — Pufendorf, De Iure naturae et gentium; — Van der Pol, Le Droit de guerre d'après les théologiens et les canonistes du moyen âge, 1911; La Guerre devant le christianisme, 1912; La Doctrine scolastique du droit de guerre, 1919; — Michel, Questions théologiques du temps présent: I. Questions de guerre, 1918; — Strattman, Weltkirche und Weltfriede, 1925 (Dutch translation); — La société internationale, edited by 4 professors of Lille, 1928: I. La doctrine by Fr. Delos, ch. 5: war; — Bulletin catholique international, in which periodical several things deserve to be read, as for example Flajolles: Que disent nos manuels sur le droit de guerre, 1930; — Delattre, La religion et la paix; — Conclusio conventus theologici Friburgensis de Bello 1932, in Docum. de Vie intell. t. X; — Deux façons d'envisager la paix, in Vie intell. t. XIV, 1932; Regout, La doctrine de la guerre juste, 1935. — Also Benedict XV, in the peace proposals of August 1, 1917.

A. The first part is proved: War is sometimes just and licit, if for some people it is the only means for vindicating its own rights of great moment, or for defending its own existence.

Hence a) God also at times commanded war, and Scripture sometimes approved it. Cf. Gen. XIV; Ex. XVII; Deut. VII, XXIII; Num. XXI, XXV; Jos. I, VI, VIII, X; I Reg. XV; II Reg. VIII; Hebr. XI, 29 sq.;

b) so holds the common doctrine of the Fathers and theologians, against the Manicheans and Quakers condemning every war as illicit, against the Wycliffites and Erasmus forbidding it to Christians, and against Luther prohibiting war against the Turks, since God visits our iniquities through them. Cf. Ambrose, de Off., l. I, c. 40; Augustine, c. Faust., l. 22, c. 74; Gregory, l. I, epist., 72;

c) the Church herself decreed war for recovering the Holy Land.

B. The second part is proved. Three conditions are required:

1. The authority of the supreme civil power, both because a private person, or a non-supreme authority, can pursue right in the judgment of a superior judge, and therefore does not need war in its own cause, and because it does not belong principally to such an authority to procure the common good or to call together the multitude, which must be done in wars.

"But since," says St. Thomas, a. 1, "the care of the republic has been entrusted to princes, it pertains to them to protect the republic of the city, or kingdom, or province subject to them. And just as they licitly defend it by the material sword against interior disturbances, when they punish evildoers,... so also it pertains to them by the warlike sword to protect the republic from exterior enemies." Because, Billuart notes,² "by this very fact, that among princes who have no superior one offends another, the offender becomes subject to the offended, in this sense, that the offended can punish the offender according to the measure of the injury." — Authority sometimes resides in the prince alone, sometimes in the prince together with the consent of the legislative assembly.

² De Charitate, diss. 7, a. 3.

2. A just, proportionate, grave, and necessary cause, which can be remedied by no peaceful means, or the necessity of the common good: "To wage war is not a matter of will, but of necessity." But since war is apt to cause immense damages, especially in our times, and to be harmful to both sides, a most grave cause is required: namely, an injury received whose reparation or repulsion cannot be had in another way, and which is so grave that it outweighs the immense evils which war brings. For to save a good of a higher order, or to avoid a greater evil, even the community itself must yield its strict right.

For defensive war, however, the conditions of just defense suffice, which is to be undertaken with the moderation of blameless protection.³ But for offensive war, "the one and only just cause of inflicting war is an injury received,"⁴ a grave injury inflicted and not repaired nor to be repaired in another way.

³ Cf. below, n. 361.

⁴ Fr. de Victoria, Relectiones, de iure belli, n. 13.

In particular the cause can be: the unjust invasion or detention of a province or city by enemies; grave injuries inflicted either upon the nation itself, or upon ambassadors, or upon citizens, which a foreign nation obstinately refuses to repair; the recovery of a grave debt, the protection of rights of great moment, or of things necessary for existence; the unjust violation, as they say, of neutrality or of a treaty, or help given to an unjust enemy; the necessity of bringing aid to an ally or another people unjustly oppressed, whence proposition 62 of the Syllabus is condemned: "The principle which they call non-intervention is to be proclaimed and observed"; religion or the right of preaching the Gospel, to be protected from aggressors against unbelievers, as St. Thomas teaches, q. 10, a. 8: "the faithful of Christ frequently move war against unbelievers, not indeed in order to compel them to believe,... but for this, that they compel them not to impede the faith of Christ." — But these do not suffice: diversity of religion or the desire of converting unbelievers to the true faith; the enlargement of one's own empire; singular progress or a superior culture of a nation which surpasses others; the power of a prince or neighboring nation to be diminished lest it be able to harm (it is illicit to kill men lest they be able to harm); one's own glory; a claim of expediency; celebrity of name; or the private good of the prince or of his family; the benefit of imparting a higher civilization even to the uncultivated or barbarians. If, however, a people altogether needs a more ample territory, as if it has more citizens than it can nourish, and there are regions little cultivated because of the paucity, ignorance, or laziness of the inhabitants, it does not seem unjust by peaceful means to occupy territories nearly empty, with equitable compensation given to the natives, because the earth is destined for the subsistence of all from primary natural right; and this right, even by moderate force, if it should be necessary, it is licit to protect.

But the cause must be a) deliberated, or subjected to mature and prudent examination, with upright men and experts in international law also consulted; b) morally certain, both because otherwise a doubt of fact would expose one to the danger of inflicting unjust damage, and because no one can be despoiled or punished unless the injustice or delict is certainly established (n. 91); c) necessary, so that other ways of satisfaction are first attempted, by which the dispute may be settled peacefully: by sending ambassadors, by recurring to mediators or arbiters, as often as this can be done without dishonor; but if the offender offers full satisfaction, the offended is bound from justice to accept it: for when the just cause ceases, the war becomes unjust.

3. Right intention of justice and of the common good, "by which, namely, it is intended either that good be promoted, or that evil be avoided." Therefore war is not to be waged from hatred, vain glory, private vengeance, desire of harming, cruelty of avenging, lust of dominating, or an implacable spirit, but from love of the common good.

Therefore the end of war is peace, or the tranquillity of order. Hence St. Thomas, a. 1, ad 3: "Even those who wage wars justly intend peace; and thus they are not contrary to peace, except an evil peace, which the Lord did not come to send upon the earth, as is said in Mt. X, 34. Whence Augustine says to Boniface (ep. 205): Peace is not sought in order that war may be exercised; but war is waged in order that peace may be acquired. Therefore be peaceful in warring, so that by conquering you may lead those whom you attack to the utility of peace."

275. Corollaries.* — 1. He who declares war without a just cause sins gravely: first and formally against charity, because he disturbs peace, which is an effect of charity; at the same time, however, against justice, on account of the unjust damages which war is apt to inflict.

2. War per se and from its nature cannot be just on both sides, namely, materially or objectively, because right cannot belong except to one or the other, since contrary rights do not exist concerning the same thing; nevertheless it can be just on both sides subjectively and formally, but per accidens from invincible ignorance or good faith.

3. In doubt concerning the justice of the cause, recourse must be had to an amicable composition or transaction, or to the arbitration of others, especially of the Supreme Pontiff, or to an international tribunal of peace or a society of nations; — but if the other party rejects recourse or refuses to obey the sentence given by the arbiter, there is now a certain injury on account of which, if the cause is proportionate, it is licit to wage war.

4. In a just war, commanders and soldiers called by precept or legitimately hired are bound to serve the community to be defended, even with danger of life: for the common good demands this. Hence they cannot desert; and per se deserters are bound to return to camp; but those who would flee to the enemy to help them would be traitors guilty of a most grave crime.

5. Soldiers — not so the learned and theologians — ordinarily are not able to judge concerning the justice of a war, nor are they bound as far as possible to inquire concerning it, unless the contrary would seem very probable, but they can presume it to be just. Even in positive doubt concerning the justice of the war, subjects who have been ordered or previously enrolled can and are bound to serve as soldiers, because presumption stands for the superior commanding; — non-subjects, or those not ordered or not hired, but free soldiers who of their own accord wish to fight, cannot enlist unless morally certain of the justice of the war, lest, namely, they involve themselves in the danger of inflicting grave injuries.

6. In a war plainly unjust, no one, neither subjects nor foreigners, can fight; because they would be cooperators in injustice. Hence they ought to withdraw from the war; but if they cannot do so without grave danger, they can exercise only actions indifferent of themselves, but they ought to abstain from fighting and hostile acts, and to surrender themselves to an enemy soldier whom they cannot avoid by flight; but if the enemy does not consent to this and nevertheless attacks, he himself now seems to become an unjust aggressor against an innocent man, and consequently the latter then probably can defend his life.

7. Today, on account of their greater security and the common good, it is strictly prohibited that merely private men, during war, involve themselves in military affairs or snatch up arms; and transgressors of this statute expose themselves to most grave penalties, even of death, which is not inflicted unjustly.

I say 1st. War is licit of itself, whether for repelling injury or for vindicating one's own right. The reason is that any society independent from another society ought to have a means of protecting itself against injury and of vindicating its own right; but sometimes no other means is available for obtaining this end except war. For since higher tribunals are lacking to which nations or Princes may have recourse, it remains only that, in order to obtain satisfaction from another society, they use war. - Cf. St. Thomas, 2-2, q. 40, art. 1.

I say 2nd. For a just and licit war, the following are necessarily required: 1st. legitimate authority, that is, supreme authority, acknowledging no other superior in civil matters, and the reason is that where a greater authority is had, this authority ought to judge concerning the dispute; 2nd. a just and grave cause, which is preponderant over the inconveniences that will follow from the war, e.g., a kingdom or province to be recovered, or a grave injury to the commonwealth to be repelled, or a rebellion of subjects to be repressed, etc.; 3rd. the due mode of waging war, namely that before war condign satisfaction be required from the adverse party; and if this is offered, it ought to be accepted as a matter of justice; for where war ceases to be necessary, it also ceases to be just. - Cf. St. Thomas, ibid.

I answer. To make war is not per se evil, but, with three conditions posited, namely legitimate authority of declaring war, just cause and right intention, it is licit²¹⁴ . ²¹⁴ Here q. 40, a. 1, o.

I said : «With certain conditions posited, namely legitimate authority, just cause and right intention.»

The authority required for declaring an offensive war must be supreme²¹⁷ , acknowledging no other superior in temporal matters, such as emperors, kings, certain dukes, independent states have, such as Venice, Switzerland, etc. 1° Because whoever has a superior can prosecute his right before him. But war cannot be undertaken except when there is no other way of prosecuting his right. 2° Offensive war is an act of supreme vindicative justice. Ergo it pertains to the supreme prince. But defensive war, the danger pressing, dependent princes, dukes, magistrates can declare it by natural law, since it is licit even to any private person to repel force by force. Understand, while danger and necessity last; these ceasing, they ought to seek and await from the supreme prince or independent state the judgment, power and execution of the injury to be avenged. ²¹⁷ Here q. 40, a. 1, c.

The just cause of declaring offensive war, generally speaking, is single, namely grave injury or damage inflicted, unrepaired, nor repairable in any other way.

As to right intention, war must not be waged except from intention of justice and common good, as Augustine teaches, Epist. 189²¹⁸ and lib. XXII contra Faustum, cap. 74. ²¹⁸ Formerly 205.

strike no one, wound no one; but because he knew that when they did these things as soldiers they were not homicides, but ministers of the law, and not avengers of their own injuries, but defenders of the public safety: he answered them: shake no one down, etc.; but be content with your wages.

John the Baptist was certainly speaking on behalf of men even of the New Testament; for he was the precursor of Christ.

IT IS PROVED secondly from the Heroes, praised in Scripture as saints, who waged wars: thus Abraham, Moses, Josue, Gedeon, Sampson, David, Josias, the Machabees, and others.

IT IS PROVED thirdly from holy Pontiffs, who praised wars waged by Christians, or urged that they be waged: Damasus, in Theodorus book 5, chapter 10; Gregory book 1, epistle 72; Chrysostom on Psalm 45; Nazianzen oration 3, on peace; Ambrose book 1 of Offices, chapters 40 and 41; Jerome on Micheas 4; see the Holy Doctor in the sermons of the Hexaemeron.

IT IS PROVED by reason, D. Bonaventure at the place cited, drawing on Aristotle 7 Politics, chapter 14, and D. Augustine epistle 207: because peace is necessary to the human commonwealth, that we and ours may have the means of living; but this is often impeded by acts of violence, which cannot otherwise be repelled than by war; and it is a law of nature that we repel violence, whence the opposing arguments collapse.

The Holy Doctor confirms all this on Luke 6, in these words: and he who strikes you on the cheek, etc., from D. Augustine book 1 of the City of God, chapter 21, where he says, expounding that precept: Thou shalt not kill: Against this precept they did not act who, by God's authority, waged wars, or who, bearing the person of public power, and according to its laws — that is, by the most just command of reason — punished criminals with death.

It is confirmed from the chapter Fortitudo 23, question 3, which is by D. Ambrose book 1 of Offices, chapter 27: Fortitude, which either defends the fatherland from barbarians in war, or at home defends the weak, or one's companions from robbers, is full of justice.

YOU WILL OBJECT first. It was said in Isaias 2 and Micheas 4 that wars are to be put away in the time of grace.

IT IS ANSWERED with D. Ambrose on Psalm 45 and D. Jerome on chapter 4 of Micheas, that what was foretold was the peace to come in the whole world at the time of Christ's advent, so that it might be prepared to receive the Gospel.

YOU OBJECT secondly that in the Gospel it is commanded: Matth. 5. Whoever strikes you on one cheek, offer him the other also. Matth. 26. Whoever takes up the sword shall perish by the sword. Rom. 12. Rendering to no one evil for evil.

IT IS ANSWERED from D. Augustine epistle 5 to Marcellinus, that this is forbidden lest it be done by private authority.

TAKE NOTE that in the Council of Nicaea, canon 11, those are condemned who, after first laying down the military belt lest they sacrifice to idols, returned again as a dog to its vomit, serving Pagan Emperors, Diocletian, Licinius, and others, who all dishonored the military belt of Christians unless they sacrificed to idols.

Some Fathers indeed condemn only unjust wars, or those which are occasions of sinning proximately, or dissuade men in religious orders, or urge them to enter religion, etc.

From these you have that wars even against the Turks are lawful; for if God uses the Turks for our exercise, he also uses pestilence and famine, and yet we are bound to defend ourselves, lest they overwhelm the Christian world with superstitious clouds. See Valentia at the place cited and Bellarmine, chapter 16. For the Turks are unjust possessors of Christian kingdoms.

Most excellently, after D. Augustine book 22 against Faustus, chapter 74, and epistles 5 and 207, the following wrote on this matter: D. Thomas here; Alensis part 3, question 76, member 3; Gandavus quodlibet 15, question 16; Gabriel book 4, distinction 15, question 4; Victoria relectio on the Law of War; Castro book 2 on the just punishment of heretics, chapter 14; Covarruvias relectio on the chapter Peccatum, on the rules of law, part 2, §§ 9 and 10; Bellarmine book 3 on the Morals of the Church, chapter 14; Bannes, Cajetan, and other Thomists here; Valentia question 16, point 1; Tannerus disputation 2, question 6, dubium 3; Sylvester and other Summists, under the word Bellum. The Canonists question 23, qq. 1, 2 and 3; and D. Bonaventure in the Mirror of the Soul, chapter 1, at the end, and in the Bible of the Poor, chapter 82, where from the Scriptures he gathers wondrous examples, outstandingly proving that the integrity and prayers of the Saints contribute more to victory than arms.

FIRST, then, the Holy Doctor requires three conditions for a just war in the Mirror of the Soul, chapter 1, from D. Augustine. The first is legitimate authority. So D. Augustine at the place cited, against Faustus, chapter 74. The second is a just cause; so D. Augustine question 10 on Josue. The third is a right intention; so D. Augustine epistle 207.

AS TO the first condition, only the Prince, or the Republic, ruling absolutely, can declare offensive war. Hence Princes who are parts of some whole dominion cannot do so: so Molina disputation 100, Tannerus number 30, and the common view. For defensive war, however, all peoples and Magistrates are admitted, because anyone may repel force with force.

AS TO the second, the cause must be against an enemy unjustly and gravely injuring, as D. Augustine admonishes at the place cited. I shall set out, moreover, the specific injuries for which war may be declared, which D. Bonaventure relates in the Bible of the Poor, chapter 82.

THE FIRST is if what is owed is denied: thus the sons of Israel made war on the Amorrhites, because they denied them an unmolested passage Num. 21, and D. Augustine notes this question 43 on the Book of Numbers.

NOR indeed did Julius Caesar have a just cause, on the ground that the Romans denied access to the city, as Alphonsus a Castro thinks book 2 on the penal law, chapter 14, and Covarruvias at the place cited, § 9: for he was bound to lay down his arms at the Rubicon, since he was a subject of the Republic commanding it. Nor is just war made against the Indians on the ground that they deny free access to their provinces. So Molina disputation 105, Tannerus number 34 — provided, however, they do not resist the preaching of the faith.

THE SECOND cause is for recovering one's own possessions. Thus David fought against Isboseth, 2 Reg. 2.

THE THIRD cause is to resist invaders of the Republic. Thus the Jews often fought against the Philistines, and the Machabees against Antiochus and Demetrius.

THE FOURTH, if they render aid to unjust enemies; thus David fought against Syria of Damascus, because it brought aid to Adarezer, 2 Reg. 8.

THE FIFTH, to avenge a public injury. Thus David fought against Hannon, who had dismissed the messengers with contempt, 2 Reg. 10.

THE SIXTH, against rebellious subjects, thus David 2 Reg. 20. Hence D. Gregory infers that war against pertinacious heretics is just, book 1 of the Register, chapter 72.

THE SEVENTH, if some defend public malefactors, as D. Augustine teaches, question 10 on Josue; thus in Judges 20 the Hebrews fought against the Benjamites, their own fellow-citizens.

THE EIGHTH, on account of a violated pact; you have an example in Jotham and Josaphat, 4 Reg. 3. Therefore the sole cause of a just war is injury — to be repelled by the right of defense, or compensated by the right of commutative justice, or avenged by the right of vindicative justice — and that, when due satisfaction is not otherwise rendered. So all agree with D. Augustine book 22 against Faustus, chapter 74.

Making war, however, against infidels not baptized, Castro and others approve; but the common opinion is that it is not lawful; for no Prince has a right to this except as a member of the Church, which has no right over those not subject to it.

The Archbishop of Valencia relates in his History of America that not a few armies of Christian warfare went astray in this, who, making war upon the most wretched Indians for the sake of winning them to religion, utterly destroyed that people even to extermination: the Gospel surely does not command that nations be destroyed with such savagery, but that they be redeemed with supreme humanity and patience; it would rather be fitting to spend one's own blood on their behalf by labor and long-suffering preaching than to draw their blood off into streams; for the Apostles, Christ commands, are to be as sheep, handing them not a savage sword, but the sword of the tongue — namely, the word of God, which is more penetrating than every two-edged sword.

One who makes a just war, however, CAN call others to his aid and partnership in the war; for so the Machabees demanded the alliance of the Romans, as Tannerus notes number 52; so also everywhere among the nations, while wars are waged, we have it as established that this is done. Yet I do not refuse that where the scandal of the Christian name threatens, it is not lawful; so Molina disputation 112, Azor tomus 1, book 8, chapter 25, question 14, and Tannerus as above.

But since the necessity of the one calling them is so well known that he is recognized as compelled to do so for his own defense, not to the injury of the faith, no one will deny that scandal will arise from it for anyone. By this is clear the answer to what Valentia objects disputation 3, question 16, point 2.

One CAN also lay ambushes, and is not bound to announce the battle beforehand, as the Holy Doctor notes in the Bibliotheca, chapter 82, which he proves by the examples of Abraham Genesis 14; Josue 8 and 10; and of Gedeon, Judith 8. So Tannerus.

In doubt, however, about the just cause, the condition of the possessor is the better one, as is commonly taught, according to Valentia. Nevertheless it is reasonable also to satisfy even the adverse party, as Victoria notes number 28, Molina disputation 103, Valentia question 16, point 2, Tannerus number 41.

TAKE NOTE, moreover, that a just cause once recognized does not mean war is at once to be declared, but satisfaction must first be sought, as is had in Deuteron. 20; otherwise the undertaking will be against justice, and consequently with guilt and the obligation of restitution. So Bannes dubium 8, Tannerus numbers 32 and 51, Valentia point 2, at the end.

If, however, neither party is in legitimate possession, the thing must be divided or done by the other according to the reasons, in proportion to compensation. See Tannerus number 43.

AS TO intention, it is so necessary that if the other conditions are present but this one is lacking, it does not give rise to the necessity of restitution. So, from the common view, Cajetan teaches, Bannes here, Valentia point 2, Molina tomus 1 on justice, disputation 123, Tannerus dubium 2, number 28.

War can indeed be just on both sides per accidens, if on one side there is invincible ignorance, in which way the wars of the Amorrhites with Israel seem to have been, as Tostatus teaches on Josue 10; and then, once the truth is recognized, they are bound to withdraw and restore those things that still survive, and by which they have been made richer; as Valentia notes. But Princes must first consult the learned; otherwise, in a matter of the gravest moment, they expose themselves to the danger of guilt. So Victoria on the law of war, number 20, Valentia question 16, point 2, Molina disputation 109, Tannerus disputation 2, question 6, dubium 4, number 37.

BEYOND the conditions stated, to the substance of a just war there follows the manner of conducting it. First, indeed, in the damages to be inflicted: necessary reaction is indeed allowed, both to repair the damages inflicted and to establish peace; yet not all excesses are allowed — for instance, to kill innocents, such as women and infants, as is decreed in Exodi 23, Deuteron. 20. But if God at some time commanded that even women and infants be killed — Josue 6, in Jericho; 1 Reg. 15, against Amalech — there was a special cause by the will of the supreme Lord. So Molina, Valentia, Victoria, according to Tannerus number 66.

BEYOND children and women, however, others must be presumed innocent, as is had in the chapter Innovamus, on truce and peace, from Alexander III: Innovamus, that Priests, monks, conversi, pilgrims, merchants, rustics, those going and returning, and the animals with which they plough and carry seed to the field, be let be with fitting service. To these are added Legates or Orators, in the chapter Paternarum 24, question 3. See there.

It would nevertheless be lawful per accidens, if the citadel could not otherwise be stormed, and that storming would bring very great advantage. So Tannerus number 67, with Victoria.

1. That a nation's claims are just, important, moderate, and certain.

2. That every reasonable effort has been made in vain to settle the dispute by peaceable means.

3. That war offers a fair prospect of success; for no one is justified in choosing the greater of two evils; least of all can those in authority do so, for they are the guardians of their subjects' rights.

4. That war be undertaken, as Cicero says, only as a means to bring about a just peace.