Chapter IV. On War

407. • War is a fight of a multitude against a multitude foreign to the Republic, for the cause of defending or vindicating the Republic.

Hence it differs: 1. from a brawl, which is the fight of a few against a few; 2. from sedition, which is a tumult or conflict of a multitude against the political society to which it pertains.

War is distinguished as: 1. offensive, if it is done for vindicating an injury; 2. defensive, if it is sustained for repelling force.

Principles. - I. War per se is lawful, whether for repelling an injury, or for vindicating one's own right. The reason is that any society independent from another society must have a means of protecting itself against injury and vindicating its own right; but sometimes no other means is available for obtaining this end except war. Indeed, since higher tribunals are lacking to which Nations or Princes can have recourse, it remains only that they use war for obtaining satisfaction from another society. - St. Thomas, 2. 2, q. 40, art. 1, and others.

II. For a just and lawful war, the following are necessarily required:

1. Legitimate authority, that is, supreme, acknowledging 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 the war; for example, a kingdom or province to be recovered, or a grave injury to the Republic to be driven away, or a rebellion of subjects to be repressed, etc.

3. The due manner of waging war, namely that before war fitting satisfaction be demanded from the adverse party; if this is offered, it must be accepted from justice; for where war ceases to be necessary, it also ceases to be just. - St. Thomas, ibid. - Billuart, etc.

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.

409. Resolves. - 1. Soldiers in an unjust war cannot lawfully kill enemies even for the sake of defense; if they cannot flee, they must take care lest they strike with their blows. For they themselves are unjust aggressors, and contrary rights cannot be given in the same matter. - Lacroix, and others commonly ².

² Understand that saying, that a war cannot be just on both sides, unless by accident it is judged just on both sides on account of some invincible ignorance; which in soldiers, to whom in doubt it does not pertain to define the cause, can often happen.

And as regards the resolution, what Molina has with Soto must not be neglected. "If someone," he says, "in a war which in good faith he had thought just, nevertheless in the conflict itself recognized its injustice, and while he flees sees an adversary pursuing, whom he cannot escape unless he kills him, he could kill him in defense of himself, because since he is really innocent, he is not worthy of the death which the adversary wishes to inflict on him, who, if the truth were clear to him, would have to leave him." In Lugo (De Iust., disp. 10, n. 144), to whom nevertheless these things are less pleasing (ibid., n. 176). But the inconveniences can be avoided without difficulty: for in flight the soldier can surrender himself to those pursuing, and in this way escape death.

2. The Prince, after the injustice of the war has been ascertained, must propose it to the adverse party, nor can he begin the war if competent satisfaction is offered to him; indeed even after war has begun, adequate satisfaction being offered, he is bound to leave it, if not from the rigor of justice, at least for the most part from charity, provided 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.

3. It is lawful in war to prepare ambushes and apply stratagems, so that enemies may be deceived by fallacies and cast into dangers. For these are not reputed lies, because the adversaries are deceived by their own fault, since those means are customarily applied in war. Thus it is lawful to feign flight, to use the flags of enemies, etc. But frauds are illicit which can be forestalled by no prudence, for example to infect wells and springs with poison, etc.; for these, by the common sense, fight against the rights of war. - St. Alphonsus, n. 410.

4. In a just war it is lawful to besiege cities and fortresses, to discharge cannons against them, indeed sometimes to destroy or burn monasteries and Churches, to plunder and kill in them, if, for example, the enemies use a Church as a fortress for defending themselves. - Likewise it is sometimes lawful to give a captured city over to plunder, but only for most grave reasons. - St. Alphonsus, ibid.

5. Commanders of the army and soldiers must take the greatest precaution lest they exceed after victory in punishing the vanquished; for they are ministers of legitimate vengeance, but not robbers and assassins. They must especially avoid whatever smacks of cruelty or a spirit of harming.

6. Commanders and soldiers cannot injure legates of the adverse party, because by the law of Nations they are everywhere inviolable; nor can they send spies who may secretly butcher the Prince or Commander of the army or other Nobles of the kingdom, because by the consent of all this pertains to treachery.