LEGITIMATE DEFENSE. - One who, having been compelled by the necessity of defending a right of his own or of another, concerning personal safety, or a precious good in his own possession, against the present danger of an unjust aggression, wounds or kills the aggressor, is said to act in legitimate defense, provided always that the defense be proportionate to the offense.
The lawfulness of legitimate defense flows from the very law of nature and is admitted by all positive legal systems.
I. HISTORICAL NOTES
Already Cicero, speaking of this right, ascribes it to the natural law: «A natura cuique tributum, ut se et corpus suum tueatur declinetque ea, quae ei nocitura sunt» (De Officiis, 1, 1). And Gaius: «naturalis ratio permittit se defendere» (D. 9, 2, 45).
But in Roman law it was lawful to defend oneself by killing the aggressor only when life, personal integrity and chastity were at stake; not, however, when material goods were involved, unless by reason of the time and place of the aggression personal safety was in danger (D. 48, 8, 9), or the thief attacked by striking the victim (D. 43, 16, 36, 9). Nevertheless it was not unlawful to forestall the aggressor (Cod. 3, 27, 1) and to defend in a bloody manner not only oneself but also one's own (D. 48, 8, 1 § 4).
Little is known with precision about barbarian law on the matter, because of the diversity of sources and of the opinions of interpreters; but it appears that legitimate defense was not considered an institution in itself, both because of the objective nature of ancient Germanic law and also because of the faculty granted to private individuals to avenge homicide.
Ancient canon law confirmed the lawfulness of bloody defense (c. 7, D. 1; c. 3, X, 5, 39). Innocent III circumscribed the limits of defense «cum moderamine inculpatae tutelae» (c. 18, X, 5, 12; cf. also c. 6, V, 11 in Sext.; cap. unico in Clement., V, 4). Within the scope of the lawfulness of killing in legitimate defense, the defense of worldly goods was also included, by reference to Ex. 22, 2 (3, X, 5, 12).
Canonical doctrine, already long discussed by the decretists, was further elaborated by the moral theologians, under the supervision of the ecclesiastical magisterium, which corrected the overly lax or overly rigorist judgments of both sides. Thus was reproved the judgment of those who claimed to extend the field of the lawfulness of legitimate defense to the protection of honor (Denz-U, 1117, 1180) or of material goods of very slight value or which are not actually in our possession (ibid., 1182 ff.) or who declared legitimate the killing of a judge when an unjust sentence, otherwise unavoidable, was imminent, of a false accuser or of a false witness (ibid., 1118), of the adulterer or of the wife, caught in flagrant adultery (ibid., 1119), or who granted the exculpatory ground of legitimate defense even to one who could otherwise have effectively escaped the aggression, for example, by flight (ibid., 1180). All cases in which the state of necessity does not obtain; in which the killing of the adversary is not always the most suitable means of protecting oneself or the sense of proportion among values is lacking.
On the other hand, the judgments of those who never recognized as lawful the killing of the aggressor were considered tainted with rigorism, inasmuch as in legitimate defense there is always a disproportion of values in the preference given to one's own temporal life over the eternal salvation of one's neighbor. Judgments that found an echo also in jurists and philosophers who lived more or less on the margins of Christian thought (Grotius, Kant).
In present-day canon law it is established that legitimate defense against an unjust aggressor, «si debitum servetur moderamen», excludes the crime altogether and therefore punishability; whereas, if the due moderamen is not observed, it attenuates imputability (can. 2205 § 4).
II. FOUNDATION OF LAWFULNESS
While there is agreement on the lawfulness of self-defense, within certain well-defined limits, it is more difficult to find the ultimate reason for that lawfulness, precisely because of this clash of values and of rights belonging to us and to others, and because of the universality of the precept: "Non occides," which seems to admit of no exceptions other than a special command of God.
St. Thomas (Sum. Theol., 2a-2ae, q. 64, a. 7) seems in this matter to apply the principle of the double effect (v. IMPUTABILITY OF EFFECTS).
The act of one who defends himself by killing the aggressor must be regarded under a twofold aspect: insofar as it is directed to the preservation of his own life, and insofar as it produces the killing of the aggressor. To defend oneself falls within the sphere of the fullest lawfulness, since it is connatural for man to tend to preserve his existence as much as he can. The killing of the aggressor, then, when it is not willed but only permitted for most grave reasons, is not equally imputable to the subject. But upon this much-tormented passage of St. Thomas, which has been interpreted in the most obvious sense, there has settled and taken shape a whole range of interpretations and opinions, from Azplicueta to Cardinal De Lugo, from St. Antoninus to St. Alphonsus, from Lessius to Cathrein, to Waffelaert, to Van Hove, above all because the Holy Doctor would seem to forbid the one who defends himself to intend directly the killing of the aggressor: which to some seems unacceptable, also because it would be an excessive and impractical subtlety. Hence, besides the various presentations of St. Thomas's thought, other explanations, more or less convincing, have been elaborated.
Some, in fact, explain the lawfulness by recourse to a kind of delegation that the public authority would make to one who finds himself in such circumstances. But it may be observed that the Codes speak only of the exempting effect of self-defense. Others have recourse to the necessity of protecting the social order in this manner and consequently of promoting the common good; although it might be observed that at most this provides a manifesting criterion of the lawfulness of the act and not the ratio ultima. Others appeal to the conflict of rights in a case where they are incompatible: which presupposes as proved what must be demonstrated: the lawfulness of taking the life of the aggressor. Puffendorf finds the ultimate reason in the fact that in the duties of nature no one can demand of another what he himself does not fulfill and indeed positively transgresses. He who unjustly attacks the rights of another loses his own and places himself outside the law. But even the mutual duties among men proceed in the last analysis from God and do not cease unless in some manner he wills or consents to it. Less convincing still is the theory of the necessity of right or of State authorization (Notstand und Notrecht), according to which the killing of the aggressor would be lawful for the simple fact that it is necessary for one's own preservation or permitted by the State (Carrara, Pessina, etc.).
The solution is set forth by others on the basis of these considerations. In homicide there is a twofold injury: against God, the true owner of our life; toward one's neighbor, who by the very fact that he exists has a right to life. But the aggressor is conscious of provoking a reaction, and therefore he is responsible in cause for the consequences and removes from that reaction, even when bloody, the formal character of injury; according to the saying: "volenti non fit iniuria." That this bloody defense of oneself is not contrary to the ethical order, which has its source in God, can in part be gathered from the instinct of defense innate in animals and in man, which by spontaneous impulse tends to oppose the aggressor in any way: the voice of nature seems to be the voice of the Creator.
Furthermore, coercibility, that is, the moral faculty of defending one's own right even by force under determinate conditions, is a quality of right itself, even if not an essential one, and as such derives from God, the author of things and of rights. Now the right to life is a supreme good: its coercibility must therefore extend to the utmost: it would instead be illusory and ineffective if it did not reach as far as bloody defense.
In Sacred Scripture no other elements are found that make the divine will manifest to us. There is a passage of the Old Testament (Ex. 22:2-3) that seems to permit bloody defense against the nighttime thief, but it is uncertain whether what is at issue there is a provision of positive law or of natural law. On the other hand, however, the unlawfulness of self-defense cannot be demonstrated in any way from Sacred Scripture, because the passages of Mt. 5:38-39; 26:52; Rom. 12:18-19, which would seem to present some difficulty, are commonly interpreted in the sense that only the lust for vengeance is forbidden there.
A source of the Church's doctrine is also the ecclesiastical magisterium, which has spoken in the sense indicated above.
Self-defense is therefore lawful first of all against one who is formally an unjust aggressor. It is also lawful against one who is an unjust aggressor only materially, because in practice such an examination is almost always impossible and, on the other hand, the argument drawn from the coercibility of right holds against any type of unjust aggressor.
III. CONDITIONS FOR THE LAWFULNESS OF THE DEFENDER OF THE BOND
But the faculty of resorting to physical force for the protection of a right can never be unlimited: otherwise it would be arbitrary and would overturn rather than protect the ethical and juridical order.
This holds also for the case of self-defense. After what has been said, it is easy to define these limits, which moralists summarize in the formula drawn from the Code of Justinian "inculpatae tutelae moderatione" (Cod. 8, 4, 1).
In simpler language the constitutive elements of moderatio are: unjust aggression, proportionate reaction, necessity of defense.
1. Unjust aggression
For the justifying ground of moderation it is required that the agent act to repel a violence against himself and others, a violence unjust either in substance or in manner, a violence in act. From danger is born a bond of universal brotherhood, by which the reaction and the defense receive the stamp of legitimacy from whomever they are exercised and in favor of whomever: from the egoistic and personal form of the defense of oneself and one's own, one thus rises to the altruistic and impersonal form of the defense of right.
Unjust, moreover, is the violence that is inflicted without right; and it suffices that the violence be unjust in itself, without need of referring it to the responsibility of the aggressor. Even were the latter a madman and a drunkard, if his act has given rise to the necessity of a prompt reaction, the reaction is justified. However, for it to have a justifying effect it is necessary that the violence, that is, the evil or the danger against which one reacts, be actual, at least morally.
A simple threat, not accompanied by acts or circumstances that induce in the threatened person the fear of imminent execution, would not suffice to remove the imputability of the reaction; but on the other hand the fear of imminent execution can suffice, since it is an ancient maxim of law and of common sense that "nemo tenetur exspectare donec percutiatum".
If the attack was repelled, and, without reasonable motive to fear that the aggressor will persevere and return to the attack, the person attacked goes on to further violence against him, the justification of moderation will not be invocable for these. In all these cases one must rather speak of vengeance, and at most, according to the various circumstances, depending on the sentiment that moved the subject to act, one will have the figure of excessive defense or of provocation.
2. Proportionate reaction
One cannot take from one's neighbor a supreme good for a minimal good or for a good that is otherwise defensible. By this requirement self-defense must be restricted to attacks made on life, on personal integrity, on liberty, to attacks on chastity, that are such as to put the victim in conditions of having to defend himself. The moderation for the attack on goods must be regulated morally in proportion to the intrinsic value of the good contested, to the conditions of the one threatened and to the possibilities of being able otherwise to vindicate it.
For these reasons a translation into figures is not easy, however much attempted by some. Certainly it cannot be inferior to the relatively grave matter of theft (cf. Denz-U, 181).
3. Necessity of defense
This must be examined and understood both in relation to the proportions between the reaction and the violence against which one reacts, and in relation to the possibility of otherwise avoiding it.
The proportion between the violence and the reaction must not be understood in a merely material sense, but regard must be had also to the means at the agent's disposal at the moment of the aggression, to his possibility of facing the imminent danger of acting otherwise, and to the state of his mind.
As for the inevitability of the danger, it is necessary that this be such as cannot be avoided by entreaty, by cries or by flight. The obligation to flee, however, cannot be affirmed for one who has orders to remain at his post or who cannot do so without gravely losing his own decorum. In the evaluation of all this, regard must be had to the disturbance of mind produced in the person attacked by the fear of violence or of danger.
These constitutive elements of moderation, besides being in natural law, are more or less kept in mind also in positive law. Penal codes too are accustomed to consider self-defense as a circumstance that excludes the crime (some codes, however, take it into consideration only for certain crimes).
The Italian Penal Code in force excludes punishability when one who has committed an act that would constitute a crime was constrained thereto by the necessity of defending a right of his own or of another against the actual danger of an unjust offense, provided always that the defense is proportionate to the offense (art. 52). If, moreover, the limits imposed by necessity are culpably exceeded, the act is punishable as a culpable crime (v. COLPA), provided that a penalty is envisaged for the hypothesis that it be committed with mere negligence rather than with intent (art. 55).
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Pietro Palazzini