Tertium datur: A Step Towards Squaring the Circle on the Current Meaning of Self-defence?

[Tarcisio Gazzini is Professor of International Law at the University of Padova (Italy). He is the author of The Changing Rules on the Use of Force in International Law (Manchester University Press, 2006) and a founding editor of the book series Nijhoff International Investment Law and of Journal du droit transnational]

Introduction

Self-defence has become a legally intractable subject. Article 51 of the UN Charter was drafted in 1945 having in mind the second world conflict. It is disputed whether it is fit for purpose to regulate the use of force in completely different scenarios, including the use of unilateral force against non-State actors and in the fight against terrorism. 

Article 51 was put into a straightjacket by the ICJ in the 2004 Advisory Opinion (see also the dissenting opinions by judges Higgins, Buergenthal, and Kooijmans), which confined its application to the relationships between States. State practice since 2004 hardly reflects this interpretation and one may wonder whether the Court would take the same stand today. 

The debate on the meaning of Article 51 has normally been framed in a binary choice: force used against States and against non-State actors. Such an approach has led to a variety of different positions with regard to the scope of application of Article 51 as well as the “unable or unwilling” theory. 

Introducing a Taxonomy

The post suggests departing from the binary approach in favor of a three-category taxonomy.

The first category is the traditional defensive reaction to an armed attack perpetrated by a State. The exercise of the right of self-defence by Ukraine following the brutal invasion by the Russian Federation is a textbook case. This category equally includes armed attacks carried by armed bands or irregular forces provided that they can be attributed to a State due to the control-dependence relationship (see Nicaragua case and Armed Activities on the Territory of the Congo). In this category also fall the case in which a State and a non-State actor are indistinguishable or share a “symbiotic relationship” (p. 544), such as the one existing between the Taliban government and Al Qaeda before the 2001 intervention in Afghanistan. Indeed, the legal argument based on Article 51 offered by the intervening States (see the position of the United States and the United Kingdom) has been accepted or acquiesced by the generality of States.

The second category refers to military operations against entities such as terrorist groups located on the territory of a State believed to be “unable or unwilling” to prevent them from carrying out hostile activities. State practice is quite rich but far from uniform and therefore difficult to decipher. Likewise, doctrine is abundant yet divided. The two main conflicting arguments behind the “unwilling or unable” doctrine are, one the one hand, the need to ensure that States do not become the powerless victims of those hostile activities, and, on the other hand, the unavoidably unilateral character of the military reaction. The theory has been welcomed as a benign evolution of the current legal framework, or its repudiation.

The third category breaks the binary construction of Article 51 by introducing the possibility of using military force against an entity possessing the essential requirements of statehood as it exercises independently and effectively governmental powers over a territory formally within the jurisdiction of a State. In this case, the armed attack cannot be attributed to any State as the non-State actor performs de facto governmental functions over a portion of the globe to the exclusion of any other State.

Assessing the effectiveness and independence of such an entity may be extremely difficult as both parameters are matters of degree. Such a scenario can be compared, with all due caution, to a traditional civil war during which a new subject of international may come into existence and co-exist with the central government. As pointed out by the English High Court with regard to the de facto government engaged in the Spanish Civil War (1936-1939), ‘[t]he law, based on reality of facts material to the particular case, must regard as having the essentials of sovereignty a government in effective administrative control over the territory in question and not subordinate to any other government’ (p. 245).

Consider the case of the use of force against ISIS. The exercise of effective control ISIS exercised for a few years over part of the territory of Syria and Iraq has been admitted by the Security Council (Resolution 2179), governments (see, for instance, Germany, S/2015/946; Belgium, S/2016/523) and scholars (such as Chaumette and Corten). There is however a strong resistance to assimilate ISIS to a subject of international law.

Nonetheless, it has been argued with regard to non-recognized States that “[a]n international wrongful act does not prevent the creation of a State which is a question of fact, and a State which exists in fact attains its legal status solely on the basis of existence, independent of recognition” (p. 180). This is convincing with regard to States, insurrectional movements, and, arguably, entities like ISIS. 

The existence of the subject is the factual outcome of an historical process and as such remains independent from the circumstances in which this has occurred or the violation and even the rejection of any international rules. The existence of the entity and the possible breaches of international law it has committed are two different questions. It follows that States and international organizations may react to such violations in accordance with international law, either unilaterally, or within the collective security system. 

If it is accepted that ISIS may be assimilated to an international subject, the crux of the matter becomes which rules to apply to it, considering that it repudiates all fundamental principles the international legal system is based upon. Would it be still conceivable to admit some inherent rights and obligations for ISIS in the same vein – with all due caution – as for unrecognized States)? In particular, shall jus ad bellum rules, including the prohibition on the use of military force under customary international law, govern the relations between ISIS and States?    

In the affirmative, the use of unilateral force against ISIS must be justified as self-defense. Such construction would be consistent with Article 51 interpreted as allowing a State to react militarily to an armed attack – including terrorist attacks – attributable to a subject of international law other than States. From this perspective, the military action against ISIS must keep a defensive character and comply inter alia with the principle of proportionality in the sense that its purpose is limited to halting and repelling the attack (para. 121). This seems to be the position of States like Turkey, which declared that it undertook “necessary and proportionate military actions against Daesh in Syria” (S/2015/563).

Several States, however, seem to have taken a more radical approach and aimed at destroying ISIS. During the debate leading to the adoption of SC Resolution 2249, the United Kingdom sent “a clear, unambiguous message that there will be no respite in our collective efforts to stop, suppress and destroy the Islamic State in Iraq and the Levant (ISIL)” (S/PV.7565, p. 8). In a slightly nuanced manner, for the United States the objectives of the operations against ISIS were directed at degrading its capabilities, achieving its lasting defeat, denying it safe havens and disrupting its ability to project power (S/PV.7565, p. 4). In Resolution 2249, the Security Council called upon States to use means permitted in international law “to prevent and suppress terrorist acts committed specifically by ISIL […] and to eradicate the safe haven they have established over significant parts of Iraq and Syria”. If the aim of the operations against ISIS is to destroy it, reliance on Article 51 is misplaced and the possibility of justifying otherwise the military action must be explored.

Conclusion

Introducing the three-category taxonomy obviously does not solve the complex problems concerning self-defence. Hopefully, it may contribute to clarify the conceptual framework by isolating in the first category the different forms of self-defence against a State. In this context, also thanks to the rules on State responsibility, Article 51 has proved to be quite flexible and malleable. 

Military reactions against other entities, which are included in the other two categories, are much more problematic. The distinction operated in the two last categories, however, should facilitate a better understanding of those military reactions in terms of legality, objectives and limits. 

With regard to the second category, the reaction aims at neutralizing individuals or groups of individuals by using proportionate and necessary means within the jurisdiction of a State, which has not necessarily breached any rules of international law. It is therefore not simply a matter of interpreting Article 51 as allowing the use of force against non-State actors. The attitude of the territorial State, especially with regard to a possible offer of military assistance from other States, must also be considered. 

In the last category, on the contrary, the reaction is directed against an entity assimilated to a subject of international law by virtue of the jus ad bellum rules. However, the military operations would unavoidably lose their defensive nature should they be aimed at the destruction of the entity.  

In both last two categories, the risk of stretching the notion of self-defence beyond recognition is palpable and the need to resort to the collective security system self-evident.