EJIL Talk! Book Discussion: L’acte déclencheur d’un conflit armé international – Introductory Post

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This post is part of our book discussion on Djemila Carron’s “L’acte déclencheur d’un conflit armé international“.


During the night of Thursday April 6 and Friday April 7 2017, the United States carried out airstrikes on a Syrian military base that had allegedly been used by the Syrian authorities to launch a chemical attack against its own population. As those airstrikes were, to the best of my knowledge, the first ones conducted by the United States that directly and deliberately targeted Syrian positions in Syria, the question that arose for many scholars, humanitarian actors and members of the military was the following: are the United States and Syria in an international armed conflict (IAC)? Or were they already engaged in such a conflict since the United States had been using force on the territory of Syria against the Islamic State since 2014? If there was no previous IAC between the United States and Syria on April 6, did those attacks add an IAC to the preexisting non-international armed conflict (NIAC) between the United States and the Islamic State? Did they transform (‘internationalize’) this preexisting NIAC into a IAC? Or should the attacks of April 6 and 7 fall outside the scope of international humanitarian law (IHL)?

Answering these questions, and more generally classifying hostilities, is crucial in international law. Indeed, rules applicable to an IAC – including the Geneva Conventions (GC), the first Additional Protocol (AP I), other treaties and provisions of international (and national) law and rules of customary law – create a legal framework significantly different from the one applicable in a NIAC or in the absence of a conflict. L’acte déclencheur d’un conflit armé international explores what act or acts might trigger an IAC. It uses Article 2 common to the GC as its starting point since this provision states that each of the four GC:

“shall apply to all cases of declared war or of any other armed conflict which may arise between two or more of the High Contracting Parties, even if the state of war is not recognized by one of them”.

The notion of IAC being the main entry point for the application of the core treaties of IHL, and the concept of NIAC being closely linked to the one of IAC, means that understanding the triggering act of such a conflict is a preliminary question to almost any application of IHL.

The lens of interpretation

L’acte déclencheur d’un conflit armé international answers seven important questions around the triggering act of an IAC by interpreting Article 2 common to the GC using treaty interpretation rules set out by the Vienna Convention on the Law of Treaties. Articles 31 to 33 of this treaty provide general rules of interpretation, from requiring the interpreter to look at the ordinary meaning of the terms in their context and in the light of its object and purpose, to taking into account subsequent practice and relevant rules of international law applicable between the parties, and finally to considering the travaux préparatoires and the circumstances of the conclusion of the treaty.

Using this method, the book places a strong emphasis on the interaction between: the various entry points to the law of IACs (for instance, occupation without resistance and war of national liberation); ius ad bellum and ius in bello; IHL and other domains of international law (among them, human rights law); and IACs and NIACs for the specific objective of defining the triggering act of an IAC. It also draws on the travaux préparatoires of the GC and AP I, as well as States practice, notably through the definition of IACs provided by military manuals from many different countries.

The definition of the triggering act of an IAC

The book is divided into seven questions, each concerning a different aspect of the triggering act of an IAC. After explaining in the first one that the words “between two or more of the High Contracting Parties” of Article 2 common mean “between States Parties”, the book turns in its second question to the nature of the triggering act of an IAC: what kind of actions can potentially lead to an IAC? According to an interpretation of Article 2 common, only a physical act directly leading to death or injury of human beings or damage or destruction of objects can trigger an IAC. Therefore, tensions between States, economic pressures, breakdown of diplomatic relations or even the presence of the troops of one State on the territory of another (without any use of force) would not lead to an IAC. This analysis is also valid for cyber-attacks. In addition, contrary to the majority view and that of the ICRC, the book argues that the mere capture of a soldier in the absence of an occupation or hostilities does not trigger an IAC since, among other arguments, the status of prisoner of war makes little sense outside of one of those situations.

The controversial question of the threshold of violence for the existence of an IAC is at the center of the third question. There are two main positions on the subject. The traditional view (Pictet’s first shot theory) maintains that no threshold of violence must be reached before an IAC begins. A more recent position (see Conference Report The Hague 2010) holds that a level of violence is required and excludes, for instance, isolated incidents, border clashes and skirmishes from the definition of IAC. This section defends the traditional view for two main reasons. Firstly, because contrary to what is propounded by the tenants of the threshold theory, there is no sufficient evidence to conclude that a customary definition of IAC or subsequent practice of States includes a threshold requirement in the definition of IAC. Secondly, because IHL is the appropriate framework to govern hostilities, even minor ones, between two States.

The fourth question looks at the origin of the triggering act of an IAC. According to the interpretation of Article 2 common to the GC, this action must be carried out by a de iure or de facto organ of a State, acting in its capacity, following instructions (presumed to exist unless proved otherwise) and out of situations of errors or mistakes. For instance, following my research, when the United States in September 2016 mistakenly bombed a position of the Syrian army near the airport of Deir al-Zour, it did not trigger an IAC since the goal was to target positions of the Islamic State. On the control a State should have over an armed group to be a de facto organ of a State for the specific question of the triggering act, the book defends an original position departing from the tests developed by the ICJ and the ICTY. It proposes that a use of force against a State committed by an armed group is attributable to a second State, and thus triggers an IAC, only if this second State has a strict control over this armed group for the specific use of force in question.

After dealing with the origin of the triggering act, the book logically turns to the target of such an act. This is clearly one of the most controversial part of my research as the position defended clearly departs from the majority view. In my opinion, for an IAC to exist, it is not necessary for a State to attack military objects or persons of another State. In the same vein, the mere fact that a State deploys military activities on the territory of another State without its consent is not sufficient for such a conflict to take place. On this matter, the book (and an article I wrote) elaborates on a rule and three exceptions for a rapid classification of transnational conflicts. According to the rule, a use of force from a State on the territory of another one leads to an IAC only if it can be shown that it targeted: 1) an object/individual attacked for its own sake, like criminals fleeing from one State to another (classification: no armed conflict); 2) another State (classification: IAC between the intervening State and the State targeted); or 3) an organized armed group if a certain threshold of violence is reached (classification: NIAC). In other words, and to come back to our introductory example, when the United States used force against the Islamic State in Syria, there was a NIAC between the United States and the Islamic State. Syria’s consent or absence of consent had no significance in this classification exercise as it brings a ius ad bellum element in a ius in bello matter. This said, when the United States directly targeted the Syrian base on April 6 and 7 2017, it clearly launches an IAC between Syria and itself, leading to a double-classification of IAC and NIAC.

On the need of an animus belligerendi for an IAC to exist (question 6), L’acte déclencheur d’un conflit armé international has a clear answer: no animus belligerendi is required. The shift in 1949 from the notion of war to the one of IAC had precisely the goal of separating the application of IHL from States’ intents and declarations. Nevertheless, an examination of the various types of “animus” that could be relevant for the existence of an IAC leads to the conclusion that for such conflict to emerge, a State should nevertheless have the intent to use force against another. It is thus important to distinguish the animus to use force from the one to create a state of war or to be in an IAC.

The book ends with a complementary question on the internationalization of a NIAC into a single IAC. As for the control for the triggering act developed in question four, the book departs here from the control tests developed by the ICJ and the ICTY and proposes a new test for internationalization that should be general in its scope (like the overall control developed by the ICTY for internationalization or the complete dependence control articulated by the ICJ for responsibility) but strict in terms of intensity. As a result, in my opinion, the airstrikes of April 6 and 7 carried out by the United States in Syria simply added an IAC to the preexisting NIAC between the United States and the Islamic State. Indeed, there was clearly no general and strict control of the United States or of Syria over the Islamic State.


This post identifies the main elements of the definition of the triggering act of an IAC presented in L’acte déclencheur d’un conflit armé international. If the reasoning for each part appears complex, the book ends with a definition encompassed in one paragraph. There are many elements that I would have liked to have developed in more detail in this short post, and I am looking forward to the discussion to specify some of the interesting parts of this book.

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Jacob Ciesielczuk says

July 15, 2017

Dear Djemila,

thank you for this excellent post. My first question would be, is there an English version of that book or is it going to be translated to English any time soon ?
Given my personal interest in IHL and specifically armed conflict classification, I would love to read it. However, due to my lack of the proficiency in French, it is impossible.
I would like to enquiry on what basis, the book departs from the tests developed by the ICJ and the ICTY?
Also, could please elaborate a bit more on what do you mean by 'strict control over armed group'? I presume that the book argues that the higher threshold should be applied than these established in Nicaragua and Tadic?
I am looking forward to your response!