The two principal requirements that are derived from the requirement of neces- sity are immediacy and retreat. The requirement that the expected danger to the legitimate interest of the person attacked should be immediate is so important, that the opinion has been expressed that it constitutes the main substance of the requirement of necessity.626The reason for this is simple: in the absence of imme- diate danger, defensive force is not necessary, since other non-violent ways of action exist, first and foremost an appeal for assistance from the various law enforcement authorities. In contrast to the requirement of immediacy that enjoys almost complete consensus, the duty to retreat has evoked much dispute. The requirement is that before making use of defensive force (or lethal defensive force), the attacked person must also exhaust the means of safe retreat—if this is possible. The principal reason627for this requirement is simple, at least on the sur- face: if the attacked person makes a safe retreat, the need for defensive force no longer exists; necessity does not exist, and private defence, including the violence that it involves, becomes superfluous. These two requirements—of imminent danger and retreat—are very central to the framework of the law of private defence and they will therefore be discussed separately and at length further on.628
A consideration that has importance at times in the evaluation of necessity is the possibility of bringing the attack to an end without force, but by demanding that the aggressor cease his attack. Although in many cases such a demand would be pointless, there are cases where it is definitely likely to achieve the goals of private defence, in which case defensive force would no longer be necessary. A typical case like this, which is often mentioned in the literature,629is trespass. It is desirable to
625See what is said above in the text accompanying nn 446–48 and also Chs 5.2 and 5.3 below.
626Feller, n 14 above, vol 2 at 28.
627But not the only one, for in my opinion—as I will show further on—the duty to retreat is also (and principally) derived from the principle of proportionality.
628See sections 3.7 and 3.9 below.
629See, eg, Archbold, n 487 above, at 1664; Williams (1983), n 1 above, at 516.
require that the attacked person (who holds the land) should precede his defensive force (to repel the trespasser) with a demand, and allow the trespasser to fulfil it.
This is also true with regard to defence of propertyin general—here too there is good reason to expect that the actor should demand that the aggressor cease his attack or return his property before using defensive force.630Another typical case in which there is good reason to impose such a demand is the case discussed above in another context631—prior consent by the person attacked to the attack by the aggressor. Retracting such consent may definitely make defensive force superfluous.
Another consideration in the evaluation of necessity, which is similar to the consideration described above in that it is based on the desirable possibility that words will render physical force superfluous, is the possibility of bringing the attack to an end by relying solely on a warning. In Jewish law, the ‘pursuer’
(‘rodef’—the aggressor) must be given a warning before one kills him. Although not all the reasons for this are relevant for our discussion,632there is no doubt that the possibility of avoiding physical force by using a warning is a consideration that should be taken into account in the evaluation of necessity in modern criminal law. In the Israeli Supreme Court’s rulings this consideration is given expression by raising the possibility of ‘firing warning shots into the sky’ before shooting a person.633
It is emphasised that, both with regard to the possibility of a prior demand to the aggressor that he cease his attack and with regard to the possibility of sufficing with a warning, the actor should not be expected to exhaust these possibilities if this would bring about more severe endangerment of his legitimate interest.
Therefore, non-use of such endangering options should not be considered as a negation of the necessity of the defensive action.
Two additional modes of action that may be available to the actor and that may have importance for the evaluation of compliance with the necessity requirement are succumbing to illegal arrest, andrelinquishment of threatened property. The first is discussed above, as part of the discussion of the character of the attack, and the second is to be discussed in the appropriate context from a substantive point of view—alongside the duty to retreat, for such a relinquishment is a specific case of retreat or, at least, a case which is parallel to retreat.634
630 Thus, eg, the formulators of the American MPC chose, in their casuistic manner, to set forth explicitly both a duty to make a demand prior to the exercise of defensive force on property, and also three exceptions to this same demand—see s 3.06(3)(a)(I), (II), (III) of the MPC. See, also Perkins and Boyce, n 85 above, at 1156; Russell, n 40 above, at 682.
631 See section 3.4.4 above.
632 Varhaftig, n 123 above, at 78. A possible reason for this demand, that is irrelevant for our pre- sent discussion, concerns the formal conditions for the performance of the death sentence by the court—see Finkelman, n 25 above, at 1281–84.
633 The ruling in CA 319/71 Ahmed and Sheikh v The State of Israel PD 26 (1) 309, at 312 and the ruling in CA 410/71 Horowitz v The State of Israel PD 26 (1) 624, at 628.
634 See (correspondingly) sections 3.4.3 above and 3.9.7 below.
An additional option for the attacked person, which typically appears in the lit- erature,635is the full defence of the legitimate interest at stake by means of a sub- sequent appeal to the court. This option is, in my opinion, limited to injuries to the property of the attacked person, injuries for which it is sometimes possible to obtain a full remedy from the court that will restore the situation to its former state. This factor, in the evaluation of necessity, must also include the injury to the legitimate interest of the attacked person that is caused by waiting until the termi- nation of the legal process, and by the legal process itself. Evaluation of the possi- bility that the victim will be awarded compensation for the damage obviously includes factors such as the ability to locate the aggressor and the possibility of being paid by him. This option of an appeal to the court also bears marks of a retreat, and usually such a temporary waiver will involve an injury of some sort to the legitimate interest of the attacked person, although the injury will be less, for example, than the total loss of the property.
An additional factor that was discussed before and that should be referred to here also, because of the importance that it may have in the evaluation of the necessity of the defensive act, is the probability of the occurrence of danger.636 Yet, while this factor has great importance for the evaluation of the existence of the requirement of proportionality, it has no similar importance for the present subject of discussion, namely, the evaluation of compliance with the necessity requirement. For even if there is little reason to anticipate the occurrence of dan- ger, as long as it is a real possibility, it cannot, at the threshold, negate the neces- sity for defensive force. In contrast, if the chances for realisation of the danger are very slight, this will usually have the effect of negating the necessity for defensive force.
A general factor that has great importance in the evaluation of necessity is the balance of power between the sides to the conflict, namely the attacked person or the one who defends him versus the aggressor. In the evaluation of the power dynamic not only the physical strength of the parties, their ‘strategic’ positions and their equipment (weapons), should be taken into account, but also their relevant skills. While it will not usually be necessary, for example, to use a lethal weapon to repel an unarmed aggressor, especially if the attacked person is not weak in com- parison to the aggressor, such a necessity could exist if the aggressor has special capabilities, such as outstanding skills in the art of combat. Insofar as the relative strengths work to the disadvantage of the person attacked (or the one who defends him), the use of harsher means to repel the aggressor may be justified within the framework of private defence.
635See Robinson (1984), n 37 above, vol 2 at 566 and Gorr, n 191 above, at 260. Although Gorr raises this possibility while considering its influence on evaluation of the requirement for proportion- ality, yet in my opinion, it is also very relevant for the requirement of necessity.
636See section 3.5.2 above.