War and the Catholic Moral Principles

by
John A. McHugh, O.P.
and
Charles J. Callan, O.P.

Taken From Moral Theology, A Complete Course, Vol. 1.

New York City, Joseph F. Wagner, Inc.,
May 24, 1958

1376.
War is defined as a state of conflict between two or more sovereign nations carried on by force of arms.
(a) It is a state of conflict, and so differs from passing conflicts, such as battles, skirmishes, campaigns. The enemy in war is not only those with whom one is actually fighting, but all those who side with them, as counsellors, helpers, etc.
(b) War is between sovereign nations, and so differs from civil war, sedition, riots, duels. Moreover, war is made by nation against nation, not against particular individuals or groups of individuals within a nation.
(c) It is carried on by force of arms, and soldiers from trade war, rivalry in preparedness for war, embargo, blockade, breach of diplomatic relations, etc.

1377.
There are two kinds of war, just and unjust.
(a) War is just when undertaken for a right cause (e.g., the independence of the nation);
(b) It is unjust when undertaken for a wrong cause (e.g., the enslavement of a nation).

1378.
Just war is either offensive or defensive.
(a) Offensive war is attack made on an enemy in order to avenge an injury or enforce a right (e.g., invasion of the enemy’s territory to obtain compensation for damages inflicted by him);
(b) Defensive war is resistance to unjust attack made or menaced by an enemy (e.g., war made on the invader of one’s country).

1379.
Just war is called defensive in two senses.
(a) In the strict sense, it is defensive when the nation whose rights are unjustly attacked does not initiate hostilities, that is, does not declare or begin the war.
(b) In a less strict sense, it is defensive when the nation unjustly attacked declares war or strikes the first blow. Thus, if the innocent nation knew that the enemy was secretly preparing war against its independence, it would be on the defensive, even though it declared war.

1380.
War is not against the law of God.
(a) Under the law of nature Melchisedech blessed Abraham returning from victory over the four kings (Gen., xiv. 18—20).
(b) Under the written law, God many times ordered or approved of war, as can be seen from Exodus and following books in numerous places.
(c) Under the New Law, John the Baptist acknowledged the lawfulness of the soldier’s profession (Luke, iii. 14), a centurion was praised by Christ (Matt., viii. 10), Acts, x. 2, speaks of the officer Cornelius as a religious man, and St. Paul lauds warriors of the Old Testament such as Gedeon, Barac, Samson, etc. (Heb., xi. 32—34). Our Lord Himself used physical force against evildoers (John, ii. 14 sqq.).

1381.
Certain sayings of our Lord — for example, that those who take the sword shall perish by the sword (Matt., xxvi. 52), and that one should not resist evil (Matt., v. 39) — are not an endorsement of extreme pacifism, but are respectively a condemnation of those who without due authority have recourse to violence, and a counsel of perfection, when this serves better the honor of God or the good of the neighbor. Moreover, these words of Christ were addressed, not to states, which are responsible for the welfare of their members, but to individuals. The Quakers have done excellent service for the cause of world peace, but their teaching that all war is contrary to the law of Christ cannot be admitted. The spirit of the Gospel includes justice as well as love.

1382.
War is not against the law of the Church.
(a) The Church has never condemned war as such. She has always labored for the promotion of peace or for the lessening of the evils of wars that could not be prevented; but her official declarations and the writings of the Fathers and Doctors show that she recognized that recourse to arms by nations is not necessarily sinful.
(b) The Church has put her approval on some wars as necessary and laudable. Thus, the Crusades, to which the salvation of Christian civilization is due, were promoted by the Church; military orders for the defense of the Holy Sepulchre were instituted by her, and she has raised to the honors of the altar soldiers like Sebastian, Maurice, and Martin of Tours.

1383.
War is not against the law of nature.
(a) As the law of nature allows even a private individual to use force to drive off an unjust aggressor, it cannot be unlawful for a nation to have recourse to defensive war when its rights are invaded.
(b) As the law of nature allows the individual to seek satisfaction for injury and restitution for loss, it cannot be unlawful for a nation to make offensive war when another nation will not make reparation, unless compelled to it by force. If physical coercion were unlawful, a conscienceless nation would take advantage of this at the expense of other nations, and thus a premium would be set on iniquity.

1384.
Like every other act, war is not morally good, unless its object, its purpose and its circumstances are in accord with right. War is not lawful, therefore, unless the three following conditions exist:
(a) Hostilities must be authorized by the public authority, for the care of the State against internal and external disturbances has been committed to the ruler (Rom., xii. 4; Ps. lxxxi. 4), and the individual or the subject state can have recourse for protection of its rights to the higher authority.
(b) There must be a just cause for war, that is, some fault on the side of the other nation; for, if a nation may not use force against its own subjects without sufficient reason, much less may it do so against those who are not its subjects.
(c) There must be a right intention, that is, the desire to obtain some good or to ward off some evil. Even if war is declared by the proper authority and there is a sufficient reason for it, those who take part in the war are guilty of sin if they have evil motives, such as the exercise of cruelty, revenge, pride, or avarice. To delight in war because one loves excitement or wishes to show one’s skill or get promotion, is not a right frame of mind.

1385.
What public authority has the right to declare war?
(a) Ordinarily, only the sovereign power — that is, the person or body in whom the chief authority is vested according to the constitution of the nation — can make war. War is an act of the nation, and hence only the authority that represents the nation can make war. Subordinate bodies in a confederation or union of states have the right to make war, if custom or law allows it.
(b) In extraordinary circumstances, an inferior power can authorize war, as when war is necessary and it is impossible to await a declaration from the sovereign power. Thus, if a province were suddenly invaded, it would be lawful for the head of the province to make war on the invaders at once. It seems, indeed, that the head of a province could justly authorize the invasion of a neighboring state, to protect such province against aggressions, if the central authority would do nothing; for such a war would be really defensive.

1386.
In order that the cause of war be just, it is necessary that the enemy nation has done or now menaces an injury which cannot be repaired without war, and which is so serious that the evils of war are less than that of toleration.
(a) Thus, a serious injury or grave dishonor inflicted by another nation is the only just cause for the armed conflict which constitutes war, for war is exercised as a punishment or a compulsion, and these are unjust if no grave and formal fault is supposed.
(b) Only an injury that cannot be otherwise repaired is a just cause for war, because a state has no right to use force against another sovereign state except as a last resort. Hence, if the country at fault has already made satisfaction or has promised to make satisfaction, war should not be declared.
(c) Only an injury so grave that it outweighs the risks and losses of war is a justification for making war, for when two effects, one good and one evil, follow from an act, there must be a proportionately grave reason for permitting the evil effect before acting (see 104, 105). It would be wrong to avenge some small insult or some isolated injury at the expense of immense treasure and enormous loss of life. Modern warfare is so devastating that only the gravest reasons known to society can authorize it. For, according to scientists, a single H-bomb may cause death and destruction over a wide area, perhaps the space of a hundred square miles. In view of the havoc which is foreseen to outweigh the benefits of victory, it could happen that a nation with justice on its side and the potential to wage war would nevertheless not be justified in waging war (see 1410). This destructive power of modern weapons, however, need not imply a sweeping condemnation of all warfare. Spiritual values, e.g., freedom from tyranny, freedom to worship God, still hold primacy over material values and can be deemed so precious as to outweigh the great loss off lives and property involved in defending them or recovering them through modern warfare. “A people menaced by, or already victims of unjust aggression, if it desires to think and to act in a Christian manner, cannot remain in passive indifference.” (Pope Pius XII, Christmas Message of 1948).

1387.
In comparing the advantages and disadvantages of war, one should take into consideration, not only the losses oneself will suffer, but also the losses that will be suffered by others.
(a) Thus, if the enemy nation will be ruined as the price of one’s obtaining some small right, charity would urge that one abstain from war.
(b) If the world in general or posterity will suffer greater evils materially or spiritually than a nation is now suffering from the denial of some non-essential right, charity at least should rule out a declaration of war.

1388.
Is there a just reason for war, when, a fault has been committed on both sides?
(a) If the injuries are about equal and still in being, there is no reason for war, for neither nation is in a position to accuse the other of injustice.
(b) If the injuries are quite unequal or one nation has shown a willingness to cease from injury, the less guilty nation has a right to make war; but it should first clear itself of injustice, before it proceeds to chastize injustice in the other.

1389.
Sufficient causes for making war are:
(a) Grave injury to the honor of a nation, such as insult to its ruler or ambassadors (II Kings, x.);
(b) Injury to the natural right of the nation to existence, self-preservation, property, free action within its own sphere; thus, a people may make war to defend their independence (I Mach., iii. 59), to recover territory taken from them unjustly, to resist a violation of neutrality (II Kings, viii. 5), to protect their own citizens and commerce;
(c) Injury to the rights of the nation under positive law. Thus, a nation may make war to uphold important international agreements, to enforce the observance of treaties, and the like.

1390.
Injury done to a third nation or to the subjects of a third nation may also be a sufficient reason for war.
(a) Thus, out of justice, a nation is obliged to help its allies in a just war; for to help those with whose interests one’s own interests are involved is only self-defense.
(b) Out of charity, a nation that has the right of intervention may lawfully go to war to protect a weaker nation against a stronger and bullying nation, to assist a government unjustly attacked by its subjects, or to help innocent; subjects who are tyrannized over by their government.

1391.
Is it lawful to go to war over religion or morality?
(a) Error in the religion or immorality in the practices of another people is not a sufficient reason for making war on them. No one can be forced to believe, says St. Augustine; and it is likewise true that no one can be forced to love virtue, whereas external conformity without conviction or love is hypocritical. Moreover, a nation has no authority to correct the sins of those not subject to it. Hence, it would not be right to attack a people for the sole reason that it was pagan or polygamous.
(b) Interference, however, with the religious rights of others or sinful practices that are injurious to others are a sufficient reason for war. No war ever had a more legitimate cause than the Crusades, which were undertaken to defend the Christian religion against the unspeakable atrocities of infidels. The cause of humanity justifies a war to put an end to such evils as cannibalism or human sacrifice.

1392.
Is it lawful to make war on another nation in order to bring to it the benefits of modern civilization?
(a) If the uncivilized nation lacks a government and suffers from disorder, it is an act of charity for a civilized nation to set up a government there which will act for the benefit of the people of the country. It is also lawful to make war on those who resist the government thus established.
(b) If the uncivilized nation has its own orderly form of government and is at peace, no other nation has the right to interfere under pretext of introducing a higher type of government. Colonial expansion is not a sufficient reason for war in such circumstances.

1393.
The following causes for war are not sufficient:
(a) Motives clearly sinful are such as do not suppose any injury done by the other nation, but rather some evil passion of pride, greed, jealousy, suspicion, or selfishness on one’s own side. Hence, it is not lawful to go to war for the glory of a ruler or of the nation, for the enlargement of one’s territory, for the advantage that may be gained over a commercial rival, for the preservation of the balance of power, or for the prevention of difficulties at home.
(b) Motives apparently just, but really sinful, are injuries done by another, if one has secretly provoked them in order to have a pretext for war. It is not right to make war on a people because of attacks made by their citizens, if these attacks were purposely caused by one’s own citizens.
(c) Motives of displeasure with another nation are not sufficient as motives for war, if the other nation has violated no right of justice, but only acted in a way not consonant with charity or friendship. Thus, the fact that one nation denies another financial assistance or the tariff advantages granted to a third nation is not a casus belli; for in matters of benevolence or privilege there is no strict claim or title, and hence no right to have recourse to arms.

1394.
Is war lawful when the justice of the cause is doubtful?
(a) The government may not declare war, unless it is morally certain that right is on its side. The consequences of war are so dreadful, and the use of force against another nation is such an extreme measure, that one should refrain from hostilities as long as one’s moral right is uncertain.
(b) Volunteers not already enlisted may not offer their services to a belligerent, unless they are morally certain that his cause is just. They participate in war from choice, and they should assure themselves that their choice is correct.
(c) Subjects called to the colors should fight for their country, even if they are in doubt about the justice of the cause, for the presumption is on the side of the government. This does not mean, however, that one should be willing to fight for one’s country, right or wrong, nor that one would be obliged to fight for a cause manifestly unjust, or to obey an order flagrantly wrong.

1395.
What is the meaning of “moral certitude” in the previous paragraph?
(a) Some moralists believe that a high degree of probability of the righteousness of his cause suffices in order that a ruler may take steps towards war.
(b) The greater number of moralists, however, hold that no degree of probability suffices. The justifying reasons must be clearer than day, and the state which goes to war must not entertain a single doubt that its cause is right. This opinion we prefer; for, if a jury may not sentence an accused to death as long as there is a reasonable doubt of his innocence, neither ought a nation to pass what is really a death sentence on hundreds or thousands of citizens as long as there exists a doubt of a compelling reason for such a course. It should, however, be observed that a ruler who has only probable evidence that an injury has been done already, may have certainty that it will be done, if it is not prevented by war.

1396.
Is it possible that the cause of war should be just on both sides?
(a) Materially or objectively, the cause of war is just only on one side, for, if one nation has the right to demand satisfaction or restitution, manifestly the other nation has no right to refuse or resist.
(b) Formally or subjectively, the cause of war is just only on one side, if the facts and obligations are known to both disputants, for the nation that knows the right of the other side and yet opposes it, does not act in good faith.
(c) Formally or subjectively, the cause of war is just on both sides, if the nation that is objectively in the wrong is subjectively persuaded that it is in the right. And, even though a government is in bad faith, its people as a rule will be in good faith as a result of not understanding the facts or merits of the controversy.

1397.
It is possible that there should be objective justice and injustice on the same side.
(a) Thus, the side which is just as regards the cause of the war, may be unjust in its conduct of the war on account of the unlawful means it employs to win, or its continuation of a hopeless struggle.
(b) The side which was just as regards the original cause of the war, may be unjust as regards a new cause that appears. Thus, a nation which goes to war to regain a lost territory, but which continues to fight for the sake of conquest after the legitimate end has been achieved, contends for a just cause at the beginning, but for an unjust cause later on.
(c) The side whose grounds are justifiable from the immediate point of view may be in the wrong if causes are traced farther back.

1398.
What are the duties before the beginning of war, according to natural law?
(a) Examination of the Cause of War --- It is clear that those charged with the declaration of war are bound to examine diligently and prayerfully into the dispute, weighing the reasons on both sides, and asking light from on high. To this end they should seek the counsel, not of a few, but of many — not merely among those who are experts in the diplomatic, legal, economic, and military aspects of the question, but also among those who will look at the matter from its ethical side and who are guided by fairness and justice. Since it is the people who have to bear the burdens of war, it seems that many wars in the past would have been prevented, had the wishes of the people been consulted.
(b) Judgment about the Merits of the Controversy — It is also clear that those who have to decide for war or peace should be impartial in their judgment. Hence, they have to be on their guard against jingoism, yellow journalism, and war interests, as well as against the pacifist or the favorer of a foreign country at the expense of his own. They should not proceed to offensive war, if their cause remains doubtful, unless the other side provokes war by refusing peaceful settlement; but, if they are in possession, they have the right to make defensive war.
(c) Judgment about the Feasibility of War — Prudence demands that, even when a nation is convinced that it has a just cause to make war, it should nevertheless refrain from this, unless it has a well-grounded expectation that war will improve matters (Luke, xiv. 31, 32). Statesmen who plunge their people into adventures whose end they cannot at all foresee, are criminals.
(d) Efforts at Peaceful Solution — Even if the cause is just and the war feasible, hostilities should not be resorted to except as a last means. Hence, pacific means — such as direct negotiation, mediation, arbitration, judicial settlement, or pressure through trade embargoes, boycotts, breach of diplomatic intercourse, etc. — should be tried in the first place.

1399.
The Chief Duties before Beginning War, According to International Law.
(a) Before war is declared, an ultimatum should be issued to the other nation, offering it final terms and a last opportunity to make apology or satisfaction.
(b) Foreigners who are in one’s territory should be given an opportunity to settle their affairs and leave the country within a reasonable time.
(c) Ambassadors and other representatives of the enemy should be provided with passports.

1400.
In itself, as said above (see 1380 sqq.), war is not unlawful. But in the light of the conditions required for a just war and of circumstances as they are today, can war at the present time be ever justifiable?
(a) If the supreme interests of a nation are at stake (such as its independence, the policies or interests vital to its existence, its obligations under convenant or treaty of peace), war can still be lawful today, for a nation cannot surrender its right to self-defense, or betray its solemn engagements of cooperative defense.
(b) If less than supreme interests are at stake, war today seems unjustifiable, for what proportion is there between the minor interests of a single or several nations and the enormous destruction of modern war and the dislocation of international security? Efforts of statesmen to secure a world pact, outlawing or renouncing war as a means of national policy, indicates progress for this view.

1401.
What are the duties during war?
(a) One should use every lawful means, according to one’s position, to secure victory for one’s country. Fighting to gain only a “stalemate,” in itself, is immoral.
(b) One should avoid such means as are opposed to natural or international law.

1402.
It is not true that all is fair in war, for even a just cause cannot sanction unjust means. The commandments of God and the laws of nations retain their force even amid the clash of arms. Examples of acts of war that are unlawful, as being opposed to the natural law are the following:
(a) Acts of irreligion, such as wanton destruction of churches or monasteries;
(b) Attempts to seduce enemy soldiers from the obedience or loyalty owed their commanders;
(c) Murder, that is, the direct killing of innocent and unarmed persons, as when one refuses quarter to soldiers who wish to surrender, fires on an officer bearing a flag of truce, sinks passenger ships not engaged on errands of war, massacres the civil population by raids from the air, places a defenseless population at the mercy of savages or criminals employed as soldiers;
(d) The dishonoring of women, the establishment of brothels for soldiers;
(e) Stealing, such as the unauthorized pillage of a town or countryside;
(f) Lying, such as breaking treaties, not keeping faith with the foe, entering into perjured agreements, circulating false stories of atrocities, forging of documents, etc.

1403.
Just war is resistance to unjust aggression, and so the same means are lawful in warfare as are lawful in private aggression.
(a) Thus, the means used against an aggressor must not be evil in themselves, as when a person protects himself against a murderer by making an innocent person a shield. Hence, in war one may not use any means that is opposed to the law of God, or to human contracts or other obligations.
(b) The means employed must be such as are really necessary for overpowering the aggressor. Thus, it is not lawful to kill a burglar when wounding him will suffice for the protection of one’s property. Likewise, in war it is not lawful to exterminate or depopulate an enemy, if the end of war can be attained by depriving the enemy of his weapons.

1404.
The principal classes of acts of war from the moral standpoint are:
(a) acts in which violence is done to things connected with religion;
(b) acts of violence against persons;
(c) acts of violence against property;
(d) acts used to conceal truth.

1405.
Acts of War and Sacred Times
(a) It is lawful to carry on warfare, offensively or defensively, on feasts, when this is necessary, just as it is lawful to do servile work on those days in case of necessity (I Mach., ii. 41; John, vii. 23).
(b) But if a suspension of hostilities can be arranged for feast days (especially for the greater ones, such as Christmas and Easter), warfare should be discontinued at those times.

1406.
Acts of War and Sacred Places
(a) It is lawful to attack a church building, if it is certainly being used for military purposes. It is also lawful to attack fortifications, and thus unintentionally to harm adjacent church buildings.
(b) It is not lawful, apart from these reasons of real military necessity, to injure sacred places or edifices.

1407.
Acts of War and Sacred Persons
(a) It is lawful for clerics to cooperate in a just war in spiritual ways, as by exhortations, prayers, and religious ministrations. Moses prayed for the armies of Israel during battle (Exod., xvii. 8 sqq.), the priests accompanied Josue around the wall of Jericho (Jos., vi. 4), and St. Bernard and other holy men preached crusades.
(b) It is not lawful, apart from necessity (as in case of conscription), for clerics to take part in actual fighting. Warfare is unbecoming in a cleric, because he is enrolled for a spiritual warfare (11 Tim., ii. 4), and because his leader, Christ, shed His own blood, not that of others (Matt., xxvi. 52). Hence, the Church forbids clerics to volunteer as soldiers (Canon 141).

1408.
The persons to whom violence is done during war are:
(a) Combatants, that is, all those who are engaged in the actual promotion of the war. Direct combatants are the fighters, such as the officers and privates of army, navy, and air force; indirect combatants are the unarmed auxiliaries of the soldiers in military ways, such as makers of munition, transporters of supplies, and those in the communication service.
(b) Non-combatants are enemy subjects who are neither fighters nor auxiliaries of the armed forces, such as chaplains and members of the medical service in the army, persons in civil life and occupation, old men, women, and children.
(c) Neutrals are those who are not subject to either of the warring contenders, and who take no part in the hostilities, although they may sympathize with one side.

1409.
The Killing or Wounding of Enemy Combatants
(a) According to natural law, it is lawful to kill or wound the enemy in battle, or to starve him by blockade, just as it is lawful in self-defense to kill or wound an unjust aggressor.
(b) According to international law, it was expressly forbidden to attack in ways that make war more cruel, without hastening the decision.

1410.
The Killing or Wounding of Non-Combatants
(a) The indirect killing of non-combatants (i.e., killing which is unintentional and unavoidable) is lawful, according to the rules given for double effect (see 103, 104). Hence, it is lawful to bombard the fortifications, arsenals, munition works, and barracks of a town, to sink passenger liners that are carrying arms or stores to the enemy, to cut off food supplies from a town or country in order to starve out its troops, although these measures will entail the deaths of some civilians as well as of combatants. Humanity requires, however, that an effort be made to spare the non-combatants, when possible, as by serving warning of attack, so that they may be removed to safety. When it is a question, however, of the use of modern weapons (the atom, hydrogen or cobalt bombs) on military targets in the vicinity of large cities, where it is foreseen that many thousands of civilians will be killed or severely wounded, then the principle of double effect seems to rule out the lawfulness of using such devastating weapons. The immediate evil effect, the slaughter of the innocents, could hardly be called incidental and only reluctantly permitted. Concretely, the inevitable results of the use of such weapons would have to be intended directly, if not as an end, at least as a means.
(b) The direct killing of non-combatants (i.e., killing which is intentional) is unlawful and constitutes the sin of murder. Obliteration bombing, the dropping of 11-bombs or atom bombs on a residential section of a city containing no military objectives, are of this character; for they are attacks on civilians. It can not be argued that such an attack would probably break down the morale of the citizens to such an extent that they would force their rulers to make peace and so save many thousands of lives. For this argument is based on the principle that a good end justifies evil means.