Book Symposium: Comparative Reasoning in International Courts and Tribunals: A Very Brief Introduction

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Trying to distil six years of research, drafting, and revision into a pithy thousand-word blog post is a difficult task. But the challenge has provided me with the opportunity to think about what I consider to be the most important lessons that I’ve drawn from the project, both in terms of the way in which I hope the book contributes to existing scholarship, as well as how the process of writing the book has changed me as a researcher.

At the outset, I’d like to thank the Editors of EJIL:Talk! for kindly hosting this symposium and the commentators for agreeing to engage with my work. In this introductory post, I will address three topics: first, how I came to write on this topic; second, the approach adopted in the book; and, third, the main findings of the book.

The Problem (or Why the Game is Worth the Candle)

In the Preface to Comparative Reasoning in International Courts and Tribunals, I state that “This is not the book I intended to write”. Whilst the language may be a touch melodramatic, that is the truth, and I thought it might be useful to explain how I came to study the use of comparative law by international courts and tribunals (ICTs) and why I think it’s a worthwhile topic to examine.

The genesis of Comparative Reasoning was my doctoral thesis, which initially set out to explore whether there is a general principle of objective liability for damage caused by so-called ‘ultra-hazardous’ activities. The beauty of general principles is that whilst scholars universally agree that they exist, their conceptions of what general principles actually are differ wildly. Such conceptual confusion provides endless room for academic debate but very little in terms of solid foundation upon which one can build a convincing normative argument.

As is well-known, one conception of general principles of law is that they are principles that are widely accepted in domestic legal systems (see here, at p.335), which may be evidenced by a comparative survey of domestic jurisdictions. However, in the course of conducting preliminary research on general principles, I noticed that ICTs rarely cited comparative law for this purpose. Instead, they often used comparative law not to establish or evidence the existence of a legal rule or principle, but rather to interpret extant legal norms.

This practice challenged a few notions that I considered to be received wisdom. The first was that domestic law could only play a role in international law through certain, well-defined channels: it could evidence a general principle of law, constitute state practice, be treated as fact, be referred to by renvoi from an international rule, or demonstrate relevant subsequent practice in the interpretation or application of a treaty. The second notion that was challenged is the centrality of Articles 31 and 32 of the Vienna Convention on the Law of Treaties (VCLT) for interpretation. My training as an international lawyer taught me to justify and evaluate interpretation against the backdrop of these provisions; indeed, even if we recognise the significant flexibility permitted within the framework of those articles, we tend to treat the VCLT rules as possessing an “evaluative dimension”, a characteristic on which I elaborate in Chapter 2 of the book. However, this approach leaves us ill-equipped to understand why interpreters may draw on material beyond that which is specified in Articles 31 and 32 of the Vienna Convention and how we might go about evaluating that practice. The comparative reasoning of ICTs poses exactly this challenge.

The Approach

Comparative Reasoning examines how five ICTs have used domestic law to interpret international law: the International Court of Justice, panels and the Appellate Body of the World Trade Organization, the European Court of Human Rights (ECtHR), international investment tribunals, and the International Criminal Tribunal for the former Yugoslavia (ICTY). Despite the varied subject-matter with which they deal and the diverse legal, historical, and political contexts in which they operate, each of these courts and tribunals has to a greater or lesser extent drawn on domestic law in order to interpret international law. By taking this kind of cross-cutting approach to the subject, the book explores whether the institutional design of the court or tribunal, the applicable law, or the context within which the jurisdiction operates has an impact on the use of comparative law.  

Comparative Reasoning does not attempt to be exhaustive; if it did, it would run the risk of being about as enjoyable to read as a phone book. Rather, for each court or tribunal, I examine instances of comparative reasoning that raise questions or issues that I consider to be relevant to interpretation more broadly. Is it justifiable, for example, for a court or tribunal to examine the domestic law of a state when interpreting a legal instrument that has been drafted solely by that state, even if the legal effects of the instrument are multilateral in nature? Does the nascency of a legal regime affect whether interpreters have recourse to comparative law? Is the interpretation of international rules that are more analogous to domestic laws, such as those in international criminal law and international investment law, more prone to comparative reasoning, and – if so – should that be the case?

(Some of) The Findings: The Interpretation of Standards

One of the principal arguments of this book is that the practice of each court or tribunal cannot be understood or evaluated divorced from the context in which it occurs. As such, drawing general conclusions is inevitably difficult. Nevertheless, I suggest that there are certain similarities in the way in which comparative law has been used by the courts and tribunals examined in the book: some have used domestic law as evidence of the intention of a state; others have used comparative law to interpret ‘standards’, understood in the Anglo-American common law sense of the term (see here at p. 58); and several have invoked comparative law to support an interpretation based on other grounds, such as literal interpretation. Each of these raises its own issues which I expand on in more detail in the book. I want to elaborate on just one of these categories in this introductory post: the use of comparative law to interpret standards.

In Anglo-American legal theory, legal standards, such as fairness or reasonableness, are often contrasted to rules. The former, such as the ubiquitous ‘reasonable person’ test, “require adjudicators (usually judges, juries, or administrators) to incorporate into the legal pronouncement a range of facts that are too broad, too variable, or too unpredictable to be cobbled into a rule” (here at pp. 25-26). Rules, on the other hand, compel “a decisionmaker to respond in a determinate way to the presence of delimited triggered facts” (here at p. 58), and are normally illustrated with the well-worn example of a speed limit on a motorway.

Just as standards exist in domestic law, so too do they exist in international law. Perhaps the paradigm is the obligation to accord fair and equitable treatment (FET) to foreign investors, a staple of bilateral investment treaties that some have suggested should be interpreted in reference to comparative law. Other examples include the guarantee of a “fair” hearing under Article 6 of the European Convention on Human Rights (ECHR) and Article 21 of the Statute of the ICTY, the requirement that permissible infringements on certain rights protected by the ECHR be “necessary in a democratic society”, or the prohibition on “inhuman” or “degrading” treatment under Article 3 of the ECHR.

When we look at the practice of international investment tribunals, the ECtHR, and the ICTY, one recurrent theme is that comparative law is often used to interpret treaty provisions that are best characterised as legal standards. Investment tribunals that have thus far invoked comparative law, for example, have done so primarily to interpret the FET obligation (see here). Similarly, in the period 2005-2015, the Grand Chamber of the ECtHR invoked comparative law in 33% of the 188 judgments it delivered, of which 73% (44 judgments) related to standards. In a recent paper, I explore this link further, showing that over the 25-year period from 1994-2019, 66.7% of the cases in which the Grand Chamber adopted consensus analysis related to standards incorporated in the Convention.

How can we explain this practice? From a doctrinal point of view, it seems clear that the rules of interpretation enshrined in Articles 31 and 32 of the VCLT don’t help us to interpret vague provisions like standards: searching for the ordinary meaning of what is “fair” or “equitable”, for example, would not get us very far, nor, in most cases, does the context or the object and purpose of the treaty lead the interpreter to a clear interpretative solution. Set adrift from the intellectual framework provided by the Vienna Convention, interpreters have recourse to what interpretative materials they might find – whether that be comparative law, judicial or arbitral case law, or analogies with other international law regimes – to demonstrate that their interpretation is anchored in empirical, seemingly-objective material.

From a theoretical point of view, viewing the practice in this light might help us to understand why comparative law is used in relation to certain legal norms and not others. But it says nothing about the question of which domestic laws should be invoked in support of an interpretation. International lawyers have often responded to this methodological question in the same way: any comparative survey should be ‘representative’, ‘comprehensive’, and ‘contextualised’. However, drawing on recent debates in comparative law scholarship (see in particular, here, here, here, and here), I suggest that we should be both more realistic about what we can expect from courts and tribunals and more critical about the benchmarks against which we assess their performance. As the practice examined in the book demonstrates, comparative law often isn’t used to evidence a general principle of law, and, that being the case, we need to think harder about which domestic laws are invoked and why those choices are made.

I hope that this introductory post has given you a flavour of some of the themes addressed in the book. I look forward to reading the posts from Richard, Yvonne, and Antonios, and I thank them again for taking the time to participate in this symposium.

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Marko says

September 14, 2020

Thank you for this excellent post. Speaking as someone who used to draft these judgments and decisions, I believe your phrase "interpreters have recourse to what interpretative materials they might find" is the truest of them all. Having recourse to comparative law, in my experience, is a last resort, when you have no other source of law to draw on. It's a last resort because it is incredibly difficult and daunting, requiring linguistic and legal expertise in up 195 domestic legal systems, as well as lots of time - and you almost never have enough time.

Daniel Peat says

September 15, 2020

Thanks for your comment, Marko.

I quite agree. I think that anyone that has been in same boat understands that whether you draw on comparative law, and which domestic jurisdictions you draw on, is a combination of chance, circumstance, and (often) capacity, both in terms of time and access to materials.

During the course of writing the book, I had coffee with an academic who was a former intern at the ICTY in the early days of the Tribunal. When I asked them how they selected the domestic jurisdictions cited in many of the early judgements, they simply said that, "Those were the only books we had at the time".

Of course, I don't think that this means that trying to understand and assess the use of comparative law is beyond the realm of legal analysis, nor that such practice should necessarily be criticised. As Antonios argues in his post (a point with which I agree in the concluding post), the practice gives us cause to reflect on how we evaluate interpretation, which, in my view, is indissoluble from the political, legal, and historical context in which it occurs.