Chapter 1

Defence of Person and Property

July 30, 2022

I. What are the justifiable causes of war?

In some cases, motives of interest operate distinctly from motives of justice.

Polybius accurately distinguishes these motives from each other, and from the beginning of the war, or that which gave occasion to the first acts of hostility; as was the case when Ascanius wounded the stag, which gave rise to the war between Turnus and Aeneas.

But though there is an actual distinction between the justifiable causes, the pretexts, and the beginning of war; yet the terms used to express them are often confounded. For what we call justifiable causes, Livy, in the speech which he has put into the mouth of the Rhodians, calls beginnings. The Rhodian deputies said, “You Romans profess to believe that your wars are successful, because they are just; nor do you boast so much of their victorious issue, as of the just principles, upon which you make them.” In which sense Aelian styles them ἀρχας πολεμων {archas polemôn} and Diodorus Siculus, in speaking of the war of the Lacedaemonians against the Eleans gives them the name of προφασεις {prophaseis} and ἀρχας {archas}.

74 The principal drift of our argument rests upon these justifiable causes, to which the sentiment of Coriolanus in Dionysius of Halicarnassus, particularly applies, he says, “in the first place, I beseech you to consider how you may find pious and just pretexts for the war.” And Demosthenes in his second Olynthiac, makes a similar observation, “I think, says he, that as in a ship, or house, or any other fabric, the lowest parts ought to be the strongest; so in all political measures the motives and pretexts ought to be laid deeply in the principles of truth and justice.”

The following language of Dion Cassius is no less applicable to the question. “Justice must be made the principal ground of our actions. For with such support there is the best hope of success to our arms. But without that, any point which may be gained for the moment has no firm ground to rest upon.”

To which may be added, the words of Cicero, who maintains those wars to be unjust, which are made without sufficient cause. And in another place, he reproves Crassus for having intended to pass the Euphrates, when there was no cause of war. Which is no less true of public than of private wars. Hence come the complaints of Seneca, “Why do we restrain homicide, and the murder of individuals, but glory in the crime of slaughter, which destroys whole nations?

Avarice and cruelty know not any bounds. By decrees of the Senate, and of the people cruel acts are authorized, and measures, which are pursued by order of the state, are forbidden to individuals.” Wars indeed undertaken by public authority are attended with certain effects of right, and have the sanction of opinion in their favour. But they are not the less criminal, when made without just cause. For which reason Alexander was not improperly styled a robber by the Scythian ambassadors, as may be seen in Quintus Curtius. Seneca and Lucan give him the same appellation; the Indian sages call him a madman; and a pirate once presumed to rank him with his own class. Justin speaks of Philip in the same terms, who, says he, in deciding a dispute between two rival kings, stripped both of their dominions with all the treachery and violence of a robber. Augustin has a pertinent remark on this subject. He says, what are unjustly acquired dominions, but the spoils of robbery? In the same strain, Lactantius says, “Men, captivated with the appearances of vain glory, give the names of virtues to their crimes.” Injury, or the75 prevention of injury forms the only justifiable cause of war. “And, in the language of the same Augustin, all the evil consequences of war are to be laid at the door of the aggressor.”

Thus the Roman Herald in a declaration of war makes a solemn appeal against the aggressor, as having violated the laws of nations, and refused proper satisfaction.


The grounds of war are as numerous as those of judicial actions. For where the power of law ceases, there war begins. Now there are methods in law to prevent intended injuries, as well as actions for those actually committed. For CIVIL INJURIES various methods of redress, or prevention are appointed by the law; and by the same power securities are provided to prevent the commission of crimes and misdemeanors. In civil cases, the party aggrieved may recover damages for the injuries sustained; and in crimes, which are offences against the public, the aggressor must submit to actual punishment. Plato, in his ninth book on laws, very properly makes the same distinction, as Homer had done before him.

Now reparation or indemnity relates to what either does or did belong to us; which gives rise to real and personal actions. These ascertain our right to the damages, which are our due, either from an agreement, or from an injury received. A right which is termed in law a right by contract, or injury. Crimes, which are offences against society, are prosecuted by indictment, that is by an accusation in the name of the sovereign.

The justifiable causes generally assigned for war are three, defence, indemnity, and punishment, all which are comprised in the declaration of Camillus against the Gauls, enumerating all things, which it is right to defend, to recover, and the encroachment on which it is right to punish.

There is an omission in this enumeration, unless the word recover be taken in its most extensive sense. For recovering by war what we have lost, includes indemnity for the past, as well as the prosecution of our claim to a debt. Plato has not omitted to notice this distinction, for he has said, “that wars are made to punish not only oppression or robbery, but also fraud and deception.” With whom Seneca agrees; for to command payment of what you owe, he calls, “an equitable sentence, stamped with the authority of the law of nations.” Indeed the form which was prescribed for the Roman heralds to use in76 declarations of war, bears exactly the same import. For therein the aggressor is charged with having neither given, paid, nor done what was due. Sallust in one of his fragments, has made a Tribune, in his harangue to the people, say, “As a final settlement of all discussions, I demand restitution according to the law of nations.”

St. Augustin, in defining those to be just wars, which are made to avenge injuries has taken the word avenge in a general sense of removing and preventing, as well as punishing aggressions. This appears to be his meaning from the following sentence of the passage, in which he does not enumerate the particular acts, which amount to injury, but adds, by way of illustration, that “the state or nation, which has neglected to punish the aggressions of its own subjects, or to make reparation for the losses occasioned by those aggressions, is a proper object of hostility and attack.” Prompted by this natural knowledge of right and wrong, the Indian King, as we are informed by Diodorus, accused Semiramis of having commenced war against him without having received any injury. Thus the Romans expostulated with the Senones, that they ought not to attack a people who had given them no provocation. Aristotle in the second book and second chapter of his Analytics, says, war generally is made upon those who have first done an injury. Quintus Curtius describes the Abian Scythians, as the best acquainted with the principles of justice of any of the Barbarians. For they declined having recourse to arms, unless provoked by aggression. A just cause then of war is an injury, which though not actually committed, threatens our persons or property with danger.


When our lives are threatened with immediate danger, it is lawful to kill the aggressor if the danger cannot be avoided.

This is the foundation of the justice of private war.

This kind of defence derives its origin from the principle of self-preservation, which nature has given to every living creature, and not from the injustice or misconduct of the aggressor.

Wherefore though he may be clear of guilt, as for instance a soldier in actual service, mistaking my person for that of another, or a madman in his frenzy, or a man walking in his sleep, none of these cases deprive me of the right of self-defence against those persons. For I am not bound to submit to the danger or77 mischief intended, any more than to expose myself to the attacks of a wild beast.


It admits of some doubt, whether those, who unintentionally obstruct our defence, or escape, which are necessary to our preservation, may be lawfully maimed or killed.

There are some, even Theologians, who think they may. And, certainly if we look to the law of nature alone, according to its principles, our own preservation should have much more weight with us, than the welfare of society. But the law of charity, especially the evangelical law, which has put our neighbour upon a level with ourselves, does not permit it.

Thomas Aquinas, if taken in a right sense, has justly observed, that in actual self-defence no man can be said to be purposely killed. Indeed, it may some times happen that there is no other way for a person to save himself, than by designedly doing an act, by which the death of an aggressor must inevitably ensue. Yet here the death of any one was not the primary object intended, but employed as the only means of security, which the moment supplied. Still it is better for the party assaulted, if he can safely do it, to repel or disable the aggressor than to shed his blood.


The danger must be immediate, which is one necessary point. Though it must be confessed, that when an assailant seizes any weapon with an apparent intention to kill me I have a right to anticipate and prevent the danger.

For in the moral as well as the natural system of things, there is no point without some breadth. But they are themselves much mistaken, and mislead others, who maintain that any degree of fear ought to be a ground for killing another, to prevent his SUPPOSED intention. It is a very just observation made by Cicero in his first book of Offices, that many wrongs proceed from fear; as when the person, who intends to hurt another, apprehends some danger to himself unless he took that method. Clearchus, in Xenophon, says, I have known some men, who partly through misrepresentation, and partly through suspicion, dreading one another, in order to prevent the supposed intentions of their adversaries, have committed the most enormous cruelties against those who neither designed, nor wished them any harm.

Cato in his speech for the Rhodians, says, “Are we to prevent them by doing first, what we say they intended to do to us?” On this subject there is a remarkable78 passage in Aulus Gellius, “When a Gladiator prepares to enter the lists for combat, such is his lot that he must either kill his adversary, or be killed himself. But the life of man is not circumscribed by the hard terms of such an over-ruling necessity, as to oblige him to do an injury to prevent him from receiving one.” Quintilian has quoted a passage from Cicero, wherein the orator asks, “Whoever made such a decision, or to whom could such a point be yielded without the most imminent danger, that you have a right to kill the person, by whom you say, you fear that you shall afterwards be killed yourself?”

To which this passage of Euripides, may be applied, “If your husband, as you say, intended to have killed you, you ought to have waited, till he actually did make the attempt.” Conformably to which Thucydides, in the first book of his history, has expressed himself in the following terms, “The issue of war is uncertain, nor ought we to be so far transported by our fears, as to engage in immediate and open hostilities.” The same writer too in his luminous description of the dangerous factions, that had arisen in the Grecian states, condemns the approbation bestowed on the person, that injured or destroyed another from whom he himself apprehended injury or destruction."

Livy says, “Men, to guard against their alarms, make themselves objects of terror; averting the danger from their own heads, by imposing upon others the necessity of either doing or suffering the evil which they themselves fear.” Vibius asked a person, that appeared armed in the forum, “Who gave you permission to shew your fear in this manner?” A question not inapplicable to the present subject, and much commended by Quintilian. Livia also in Dion says, that great infamy redounds to those, who by anticipation perpetrate the criminal act, which they fear.

Now if any one intend no immediate violence, but is found to have formed a conspiracy to destroy me by assassination, or poison, or by false accusation, perjury, or suborned witnesses, I have no right to kill him. For my knowledge of the danger may prevent it. Or even if it were evident that I could not avoid the danger without killing him; this would not establish my right to do so. For there is every presumption that my knowing it will lead me to apply for the legal remedies of prevention.

79 VI. and VII.

What must be said on the mutilation of a limb?

The loss of a limb, especially that of a principal limb in the body, is a grievous detriment.

It is nearly equal to the loss of life, to which may be added the probability of death ensuing from such a calamity; the lawfulness of killing any one, who makes such an attempt, if the danger cannot otherwise be avoided, scarce admits of a doubt.

Neither is there any more difficulty in allowing the same right for the personal defence of chastity, the preservation of which, both in the common estimation of men, and by the divine law, is deemed of equal value with life itself. We have an example of this in Cicero, Quintilian, and Plutarch, in the person of one of Marius’s tribunes, who was killed by a soldier. Among the actions of women, who have defended themselves, Heliodorus records that of Heraclea, which he calls a just defence of her injured honour.


Though some, as it has been already said, admit the lawfulness of killing the person, who attempts with open violence to destroy one’s life, yet they deem it more commendable to spare the life of another, even at the hazard of one’s own. Yet to persons, in whose preservation the public interest is involved, they will grant an exemption from this rule of forbearance. Indeed it seems unsafe to impose upon ANY, whose lives are of importance to others, a rule of forebearance so contrary to all the principles of all law. This exemption therefore must be allowed to all vested with any public office, which makes them responsible for the safety of others; as the generals who conduct armies, or the rulers of the state, and many others in similar situations; to whom may be applied the lines of Lucan—“When the lives and safety of so many nations depend upon yours, and so great a portion of the world has chosen you for its head; it is cruelty to expose yourself wilfully to death.”

IX. On the other hand it may happen, that the aggressor may be one whose person is rendered sacred and inviolable by all divine, human, and natural laws; which is the case with respect to the person of the Sovereign. For the law of nature regards not only the principles of STRICT JUSTICE, but comprises other virtues also, as temperance, fortitude, and discretion, making the observance of them in certain cases, binding as well as honourable.80 To observe these we are bound also by the law of charity.

Nor is the truth of this argument at all weakened by what Vasquez has advanced, who maintains that the Sovereign who attempts the life of an individual loses, in reality, the character of Sovereign: a doctrine fraught with equal absurdity and danger. For sovereignty cannot any more than property be forfeited by any particular act of delinquency; unless it has been previously and expressly so enacted by the fundamental laws of the state. For such a rule of forfeiture, which would be productive of universal anarchy and confusion, never has been, nor ever will be established among any civilized people. For the maxim, “that all government is framed for the benefit of the subject and not of the Sovereign,” which Vasquez and many other writers lay down as a fundamental law, though it may be generally true in theory, is by no means applicable to the question. For a thing loses not its existence, by losing some part of its utility. Nor is there sufficient consistency in his observation, that every individual desires the safety of the commonwealth on his own account, and therefore every one ought to prefer his own safety to that of the whole state. For we wish for the public welfare not on our own account alone, but also for the sake of others.

The opinion of those who think that friendship arises from necessity alone, is rejected as false, by the more sound Philosophers; as we feel a spontaneous and natural inclination towards friendly intercourse. Charity indeed often persuades, and in some instances commands us to prefer the good of many to our own single advantage. To which the following passage from Seneca is very applicable. “It is not surprising that princes, and kings, or whatever name the guardians of the public welfare may bear, should be loved with a veneration and affection, far beyond those of private friendship. For all men of sober judgment, and enlarged information deem the public interest of higher moment than their own. Their attachment therefore must be warmest to the person on whom the well being and prosperity of the state depends.” And to the same effect, St. Ambrose in his third book of Offices, says, “every man feels a greater delight in averting public than private danger.” Seneca, the writer already quoted, produces two instances, the one of Callistratus at Athens, and the other of Rutilius at Rome,81 who refused to be restored from banishment thinking it better for two individuals to suffer hardship, than for the public to be plunged into calamities.


The next object to be considered, relates to injuries affecting our property. In strict justice, it cannot be denied that we have a right to kill a robber, if such a step is inevitably necessary to the preservation of our property. For the difference between the value of life and property is overbalanced by the horror which a robber excites, and by the favourable inclination felt by all men towards the injured and innocent. From whence it follows, that regarding that right alone, a robber may be wounded or killed in his flight with the property, if it cannot otherwise be recovered. Demosthenes in his speech against Aristocrates, exclaims, “By all that is sacred, is it not a dreadful and open violation of law, not only of written law, but of that law which is the unwritten rule of all men, to be debarred from the right of using force against the robber as well as against the enemy; who is plundering your property?” Nor is it forbidden by the precepts of charity, apart from all consideration of divine and human law, unless where the property is of little value, and beneath notice; an exception, which some writers have very properly added.


The sense of the Jewish law on this point is now to be considered. The old law of Solon, to which Demosthenes, in his speech against Timocrates, appeals, agrees with it. From hence the substance of the Twelve Tables, and Plato’s maxim in his ninth book of laws were taken. For they all agree in making a distinction between a thief who steals by day, and the robber, who commits the act by night; though they differ about the REASON of this distinction. Some think this distinction arises from the difficulty of discerning by night, whether an aggressor comes with an intent to murder or steal, and therefore he ought to be treated as an assassin. Others think the distinction is made, because as it is difficult to know the person of the thief, there is less probability of recovering the goods.

In neither case do the framers of laws seem to have considered the question in its proper light. Their evident intention is to prohibit the killing of any one, merely on account82 of our property; which would happen, for instance, by killing a thief in his flight in order to recover the goods he had stolen. But if our own lives are endangered, then we are allowed to avert the danger, even at the hazard of another’s life. Nor is our having run into the danger any objection; provided it was done to preserve or to recover our goods, or to take the thief. For no imputation of guilt can attach to us in any of these cases, while we are employed in doing a lawful act, nor can it be said that we are doing wrong to another by exercising our own right.

The difference therefore made between a thief in the night and a thief in the day, arises from the difficulty of procuring sufficient evidence of the fact. So that if a thief is found killed, the person who says, that he was found by him with a destructive weapon, and killed by him in his own defence, will easily gain belief. For the Jewish law supposes this, when it treats of a thief in the act of piercing, or, as some translate it, with a stabbing instrument. This interpretation accords with the law of the twelve tables, which forbids any one to kill a thief in the day time, except he defend himself with a weapon. The presumption therefore against a thief in the night is that he defended himself in such a manner. Now the term weapon comprehends not only an instrument of iron, but as Caius interprets this law, a club, or a stone. Ulpian on the other hand, speaking of a thief taken in the night, says that the person who kills him will incur no guilt, provided that in saving his property he could not spare his life, without endangering his own. There is a presumption, as it has been already observed, in favour of the person who has killed a thief taken in the night. But if there be evidence to prove, that the life of the person who killed the thief was in no danger; then the presumption in his favour fails, and the act amounts to murder.

The law of the twelve tables indeed required, that the person who took a thief either in the day time, or in the night, should make a noise that, if possible, the magistrates or neighbours might assemble to assist him and give evidence. But as such a concourse could more easily be assembled in the day time than in the night, as Ulpian observes upon the passage before quoted from Demosthenes, the affirmation of a person declaring the danger he was in during the night is more readily believed. To83 which an additional observation may be made, that, even under equal circumstances, the danger which happens by night can be less examined, and ascertained, and therefore is the more terrible. The Jewish law therefore, no less than the Roman, acting upon the same principle of tenderness forbids us to kill any one, who has taken our goods, unless for the preservation of our own lives.

XVI.16 What has been already said of the right of defending our persons and property, though regarding chiefly private war, may nevertheless be applied to public hostilities, allowing for the difference of circumstances. For private war may be considered as an instantaneous exercise of natural right, which ceases the moment that legal redress can be obtained. Now as public war can never take place, but where judicial remedies cease to exist, it is often protracted, and the spirit of hostility inflamed by the continued accession of losses and injuries. Besides, private war extends only to self-defence, whereas sovereign powers have a right not only to avert, but to punish wrongs. From whence they are authorised to prevent a remote as well as an immediate aggression. Though the suspicion of hostile intentions, on the part of another power, may not justify the commencement of actual war, yet it calls for measures of armed prevention, and will authorise indirect hostility. Points, which will be discussed in another place.


Some writers have advanced a doctrine which can never be admitted, maintaining that the law of nations authorises one power to commence hostilities against another, whose increasing greatness awakens her alarms. As a matter of expediency such a measure may be adopted, but the principles of justice can never be advanced in its favour. The causes which entitle a war to the denomination of just are somewhat different from those of expediency alone. But to maintain that the bare probability of some remote, or future annoyance from a neighbouring state affords a just ground of hostile aggression, is a doctrine repugnant to every principle of equity. Such however is the condition of human life, that no full security can be enjoyed. The only protection against uncertain fears must be sought, not from violence, but from the divine providence, and defensive precaution.


There is another opinion, not more admissible,84 maintaining that the hostile acts of an aggressor, may be considered in the light of defensive measures, because, say the advocates of this opinion, few people are content to proportion their revenge to the injuries they have received; bounds which in all probability the party aggrieved has exceeded, and therefore in return becomes himself the aggressor. Now the excess of retaliation cannot, any more than the fear of uncertain danger, give a colour of right to the first aggression, which may be illustrated by the case of a malefactor, who can have no right to wound or kill the officers of justice in their attempts to take him, urging as a plea that he feared the punishment would exceed the offense.

The first step, which an aggressor ought to take, should be an offer of indemnity to the injured party, by the arbitration of some independent and disinterested state. And if this mediation be rejected, then his war assumes the character of a just war. Thus Hezekiah when he had not stood to the engagements made by his ancestors, being threatened with an attack from the King of Assyria on that account, acknowledged his fault, and left it to the King to assign what penalty he should pay for the offence. After he had done so, finding himself again attacked, relying on the justice of his cause, he opposed the enemy, and succeeded by the favour of God.

Pontius the Samnite, after restoration of the prizes had been made to the Romans, and the promoter of the war delivered up into their hands, said, “We have now averted the wrath of heaven, which our violation of treaties had provoked. But the supreme being who was pleased to reduce us to the necessity of restoration, was not equally pleased with the pride of the Romans, who rejected our offer.

What farther satisfaction do we owe to the Romans, or to Heaven, the arbiter of treaties? We do not shrink from submitting the measure of YOUR resentment, or of OUR punishment to the judgment of any people, or any individual.” In the same manner, when the Thebans had offered the most equitable terms to the Lacedaemonians, who still rose higher in their demands, Aristides says, that the justice of the cause changed sides and passed from the Lacedaemonians to the Thebans.