Panel 5.2 / The Need for Methodological Rigour in the Identification, Interpretation and application of cil

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5.2.1 / Vladyslav Lanovoy
The Role of International Courts and Tribunals in the Treatment of Customary International Law: A Plea for Greater Methodological Rigour

This paper criticizes the application by international courts and tribunals of the three methodological steps of identifying, applying and interpreting customary international law. It argues that these steps have been repeatedly conflated and that courts and tribunals have become increasingly assertive and laconic, and thus less accurate in their analysis of the existence and content of customary international law. The paper draws on a number of examples from the jurisprudence of the International Court of Justice, the World Trade Organization dispute settlement mechanism, the European Court of Human Rights and investor-State arbitral tribunals. The paper’s principal argument is that, irrespective of the jurisdictional limits and the particularities of the relevant applicable law, courts and tribunals should exercise greater caution in their treatment of these issues, absent which they risk improperly assuming a lawmaking role. Equally problematic is the tendency of international courts and tribunals to rely extensively on the work product of the International Law Commission, which more often than not represents a compromise resulting from last minute decisions on what should be included in the text of an article or rule and what should be included in the commentary, thus representing progressive development of international law rather than its codification proper. This is a systemic issue and poses particular problems where the evidence of State practice and opinio juris is divisive or absent. Such pronouncements by courts and tribunals go on to influence the direction of subsequent State practice or simply forestall the law and prevent it from changing and adapting to the reality of international affairs. An example of this trend is the way domestic courts rely on the pronouncements of their international peers, rarely if ever questioning the validity of their findings as far as customary international law is concerned. The paper concludes with a plea for greater methodological rigour when it comes to ascertaining the existence and content of customary international law.

5.2.2 / Letizia Lo Giacco
Eureka! On Courts’ Discretion in ‘Ascertaining’ Rules of Customary International Law

The ascertainment of rules of customary international law by courts is typically portrayed as an act of discovery engaging with the practice and opinio juris of states, as well as with the practice of international organizations, as recently spelled out in the International Law Commission Report on the Identification of Customary International Law (2018, A/CN.4/717, para. 47). Accordingly, courts just need to venture out there, explore such practice and opinio juris, and customary international law rules will be found. This legendary conception is though challenged by the alternative portrayal according to which interpreters actually operate in the context of justification, rather than discovery, in that they necessarily select and appreciate evidence of practice and opinio juris, which is far from being incontrovertible, let alone fully representative of the majority of states. In other terms, the selection and assessment of practice and opinio juris are but the result of an act of court’s discretion, which is obscurely surfacing every act of legal interpretation.

Yet, courts’ ascertainment of arguably existing rules of customary international law appears a necessary endeavour – the legend is worth believing. Owing to the authority of courts within legal orders, judicial decisions ascertaining the existence of CIL rules are typically understood as legally correct statements of the law. In particular, this actual formulation of rules of customary international law in its scope and content is necessary in order for i) ‘rules’ as such to materialize, and ii) the contestation of such rules to occur on the basis of a cognized formulation, as well as to challenge the rules of interpretation applied. Such judicial decisions represent odd creatures since, by ascertaining the existence of CIL rules, they necessarily yield effects erga omnes although they, in principle, only bind the parties to the case settled by the decision.

By engaging with judicial decisions issued by international and domestic courts in the field on international criminal law, this contribution has a twofold aim. First, it challenges the legendary portray of courts operating in the context of discovery when ascertaining existing CIL rules, by showing that they instead operate in the context of justification. Secondly, it problematizes the ambivalent nature of judicial decisions ascertaining the existence of rules of customary international (criminal) law, as producing legally binding effects inter partes and, at the same time, erga omnes effects stemming from the identification of CIL rules. As such, courts ascertaining CIL rules, formulate and let them materialize, including those that are considered necessary to the international legal order.

Such an activity hinges on the discretion that courts are afforded to make such determinations on the basis of their appreciation of state practice and opinio juris. Since this evidence lends itself to different interpretations, all the more so courts operate in the context of justification rather than discovery.

5.2.3 / Nikolaos Voulgaris
The Genesis of Customary International Law through the International Law Commission; Disentangling lex ferenda from lex lata

It falls within the mandate of the International Law Commission (ILC) not only to identify or codify existing law (lex lata), but also to record international law’s progressive development (lex ferenda) in matters when no identifiable legal rules exist. The separation between the two exercises, reflected in the Commission’s Statute ‘has proved impractical’ or ‘unworkable’ and the Commission’s modern practice has pushed the distinction aside. Nevertheless, an analysis of the ILC’s longstanding practice demonstrates that lex ferenda is of legal significance for the formation of customary rules since it directs their future development and concretisation into lex lata. In this paper, I challenge the, unexpressed yet dominant, perception that progressive development is but an appurtenance of codification. On this basis, I purport to understand the methodology guiding the identification of lex ferenda rules in international law. Given the inherent linkage between lex ferenda and lex lata when it comes to customary law, I believe that this understanding is crucial for the identification of the content of customary rules.

The argument develops in three parts. The first demonstrates that progressive development is often a necessary and important first step in the emergence of customary rules. In fact, it would be impossible to conclude any ILC project without the necessary concession that the Commission’s end product reflects, at least in part, international law’s progressive development. In many occasions the ILC has invented rules – that eventually hardened into custom – either ex nihilo, that is without any prior legal indication as to how a matter should be regulated (Article 50 of the VCLT) or when such indications where insufficient to form a positive law rule (Article 50 of the Articles on State Responsibility).

The second part argues that the elaboration of progressive development is undertheorised in international law and the ILC never developed a concomitant methodology. The ILC Statute defines ‘progressive development’ as ‘the preparation of draft conventions on subjects which have not yet been regulated by international law or in regard to which the law has not yet been sufficiently developed in the practice of States’. Given the lack of further guidance, the ILC does not follow systematically a juristic methodology in order to infer the progressive development of international law. This results in drafting provisions that have a weak claim to transforming into customary lex lata, a problem that has been haunting the ILC in recent years.

The final part aims to construct such methodology by surveying ILC practice. I argue that the elaboration of lex ferenda is subject to a specific methodology that constitutes a mixture of both policy and legal considerations. Dependent on whether lex ferenda derives ex nihilo or as a reflection of underdeveloped/conflicting practice this methodology is twofold. To bolster this thesis, I will examine at first the derivative responsibility provisions contained in the Articles on Responsibility for International Organizations where the Commission admittedly had no relevant practice to ‘build on’ and then the rule on the participation of International Organizations in the formation of custom (Conclusion 4 para 2 of the Conclusions on the Identification of Customary Law) where the ILC had to adopt a position between two conflicting views deriving from practice. The crux of my argument is that the ILC is not unrestrained when delivering its function of progressive development; an understanding of the methodology employed in the identification of lex ferenda will significantly aid the Commission in contributing to the genesis and development of customary international law. With this in mind, this paper’s cry-out is that the overlooked distinction between progressive development and codification be rediscovered.