Does One Illegality Merit Another? The Law of Belligerent Reprisals in International Law

• Author: Andrew D. Mitchell
• Pages: 04

2001] LAW OF REPRISALS 155

DOES ONE ILLEGALITY MERIT ANOTHER? THE LAW OF BELLIGERENT REPRISALS IN

INTERNATIONAL LAW

ANDREW D. MITCHELL1

I. Introduction

A special feature of international law is its lack of an effective enforcement mechanism. The law of reprisals results from that weakness, providing States a limited power of self-help to force other States to obey international law. It permits a State to take extraordinary measures, indeed measures that would otherwise be unlawful, against another State in response to a prior illegal act of the State to which the reprisal is directed. Although reprisals may have a useful deterrent effect, they can cycle out of control into an orgy of violence, and even when they do not, they typically inflict great suffering on innocents. For these reasons, successive international treaties have limited their use. Some argue that restrictions on reprisals have now gone too far, however, and are wholly out of step with political and military realities.

This article begins by defining belligerent reprisals. It then examines the conditions on the use of reprisals, including persons and objects protected from reprisals by various treaties. Once the law on reprisals is outlined, arguments for and against reprisals are critiqued to determine whether the limitations on reprisals in international law are appropriate. Finally, the article considers possible future developments and makes recommendations for clarification of certain areas of international law.

II. Belligerent Reprisals

One must distinguish reprisals from related notions and what may appear to be related situations. The Naulilaa Case (Portugal v. Germany)2 contains the classic definition of reprisal and its elements. This was an arbitration established in accordance with the Versailles Treaty.3 The Naulilaa tribunal stated:

Reprisals are an act of self-help on the part of the injured states, responding after an unsatisfied demand to an act contrary to international law on the part of the offending State . . . . They would be illegal if a previous act contrary to international law had not furnished the reason for them. They aim to impose on the offending State reparation for the offense or the return to legality in avoidance of new offenses.4

Reprisals are related but distinct from the concept of retorsion-acts that "are generally not unlawful and which are taken in response to behavior which itself is not necessarily illegal."5 In contrast, reprisals involve acts that would normally be illegal. Reprisals are also distinct from

another form of self-help, acts of self-defense.6 Both involve the application of armed force by a State, and share certain preconditions to their use.7 The difference is the purpose of the two actions.8 In self-defense, force is applied to counter "an immediate and physical danger" to the State, whereas reprisals coerce another State to abide by international law.9 Of course, reprisals are also a form of future self-defense in the sense that they may protect the State from violations of international law in the future.10

Certain rules of war are structured in such a way that their violation by one party releases other parties to the conflict from the rule. A standard reservation to the Geneva Gas Protocol of 192511 provides that the Protocol will cease to bind the State if an enemy State breaches its obligations. In effect, this agreement becomes a "prohibition on the first use of gas,"12

so that States that are attacked with a weapon prohibited by the Protocol may respond in kind without needing to rely upon the doctrine of reprisals. Indeed, Article 60(5) of the 1969 Vienna Convention on the Law of Tre

ties states, inter alia, that treaty provisions prohibiting reprisals are not, without more, terminated or suspended because of material breach.13

This article is limited to the notion of belligerent reprisals that occur during a pre-existing armed conflict. A debate is currently ongoing concerning non-belligerent reprisals and the United Nations Charter.14

Briefly, the United Nations Charter is a clear expression of the collective will of nations to find alternatives to the use of force.15 Article 2 of the Charter states, "All members shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any State, or in any manner inconsistent with the Purposes of the United Nations." Article 2 quite clearly suggests that reprisals using force are not permitted under the Charter.16 Article 2 is modified by Article 51 of the Charter, however, which states that "nothing in the present Charter shall impair the inherent right of individual . . . self-defense if an armed attack occurs against a Member of the United Nations, until the Security Council has taken measures necessary to maintain international peace and security." It might be argued that although reprisals using force are illegal under the Charter, perhaps their functional equivalent could be permitted if characterized as an act of self-defense.17 This question, which involves non-belligerent reprisals, is beyond the scope of this article.

III. Conditions on the Recourse to Reprisals

The Naulilaa Incident, referred to at the beginning of Section II, specified now well-accepted limits on the use of reprisals. Specifically, reprisals (1) can only be executed by agencies or instrumentalities of a State; (2) must be proportionate; and (3) must follow a failed attempt to resolve the

violation by peaceful negotiation.18 Applying these rules to the facts in Naulilaa, the tribunal found Germany's reprisal illegal, since the acts were not a proportionate response and had not been preceded by any attempts at negotiation.19 This formulation is important because it sets out the conditions for recourse to reprisals. While treaties have significantly changed the scope of the persons and objects that may be the subject of reprisals, they have not altered these principles relating to recourse to reprisals in general, which remain governed by customary international law.20 This article considers these elements in some detail below.

A. Prior Violation of International Law

The State that is the subject of a reprisal must be the State that perpetrated the prior violation of international law or its ally.21 The prior violation must be of the law regulating the conduct of war22-not simply a violation of the laws regulating resort to force.23 Therefore, a State cannot use the doctrine of reprisals to justify otherwise unlawful means or methods of warfare against a State whose only illegal act was initiating a war of aggression. This is because the law regulating the conduct of war applies to all parties regardless of any breach of the laws regulating resort to

force.24 Indeed, as Sir Hersch Lauterpacht recognized, this is necessary to avoid the ridiculous situation "in which one side would be bound by the rules of warfare without benefiting from them and the other side would benefit from them without being bound by them."25 It also prevents each side from accusing the other of aggression and invoking the doctrine of reprisals to avoid the law regulating the conduct of war.26

B. Proportionality

Although it is clear that reprisals must be proportionate, there is some disagreement as to what act or object the reprisal needs to be measured against.27 The traditional view is that reprisals should be proportionate to the initial violation of international law.28 McDougal and Feliciano argue, however, that the reprisal must be sufficient but not excessive in forcing compliance with international law, not necessarily proportionate to the initial violation.29

While it is appropriate to bear the purpose of the reprisal in mind, it does not seem correct to suggest, as McDougal and Feliciano do,30 that reprisals may exceed the initial violation in terms of violence. This would clearly increase the risk of escalating the conflict. Instead, the purpose should impose an additional limitation on the use of the reprisal so that the

reprisal must not exceed either the initial violation or the minimum level of force required to induce compliance with international law.31 Even so, determining whether a reprisal is proportionate can still be a crude exercise,32 particularly when reprisals are not in kind, for example where a State attacks enemy soldiers with prohibited weapons in retaliation for enemy attacks on civilian targets.

C. Last Resort

Reprisals must only be used after the State attempts other reasonable methods of seeking redress short of force that have failed. In circumstances where there is a need to act quickly to protect civilians or troops from further injuries arising from violations of international law, or where it is clear that the enemy will not respond to other approaches, no other attempts may be required before resort to reprisal is permissible.33 The requirement of last resort remains appropriate as a general rule, however, because it recognizes the drastic nature of reprisals and the likelihood of horrific consequences.

IV. Persons and Objects Protected Against Reprisals

A. Geneva Conventions of 1929

The 1899 and 1907 Hague Regulations on the Law of Land Warfare34

contained no direct reference to reprisals, possibly out of concern that doing so would be seen as condoning their use. Article 27 of the Hague Regulations of 1907, however, implicitly prohibited reprisals against cultural property.35 The frequent use of reprisals during the First World War,36 particularly against prisoners of war, led to the first explicit prohibition on

their use against particular targets in Article 2 of the 1929 Convention Relative to the Treatment of Prisoners of War.37 This Convention prohibited reprisals against prisoners of war,38 an arguably legal practice under international law until that time. Although the prohibition was unanimously accepted by the Convention, arguments were made...