In this chapter, I examine the extent to which courts in Switzerland respect the methods of treaty interpretation required by international law, and whether they interpret treaties in a predictable, clear, and consistent way. I first provide a short (and, given the breadth of the issue, inevitably schematic) overview of domestic courts’ approach to treaty interpretation in general. I then zoom in on Swiss courts. Four clusters of problems can be identified in Switzerland and in other States. First, courts tend to ignore the methods of treaty interpretation. Second, they often assert a given interpretation without substantiating this conclusion, and they selectively rely on auxiliary means instead of direct manifestations of State practice on treaty interpretation. Third, the practice is highly self-referential (when courts cite other authorities of their own State) and even circular (when they cite themselves). Finally, courts’ reasoning tends to be imprecise, uneven, and superficial.
Compared to treaty law, there is little domestic judicial practice pertaining to customary international law (cil) and general principles of international law (gpil). Nonetheless, there are important reasons for studying their interpretation by domestic courts. In the first section of this chapter, I examine the domestic judicial practice of cil, with an emphasis on the Swiss practice. The second section is devoted to domestic courts’ interpretation of gpil. After this tour d’horizon of the case law, I provide an overall evaluation thereof. The four problems the Swiss practice reveals roughly mirror those identified with regard to treaty law and are, again, also noticeable in foreign rulings. These problems consist in a neglect of unwritten law, a lack of substantiation and a selective reliance on auxiliary means, a frequent circularity and self-referentiality, and a tendency towards imprecise, irregular, superficial, and repetitive reasoning.
This chapter is devoted to the specific methods governing the interpretation of international law, and to the reasons for using these methods in particular. I claim that States, to honor their international obligations, must use the interpretative methods of international law, namely textual, systematic, teleological, and historical interpretation. Contrary to what is often assumed, the interpretative methods of domestic and international law share the same traits. Differences between them are due to some features of domestic vs. international lawmaking. To identify the interpretative methods of international law, I use domestic law and legal theory, the Vienna Convention on the Law of Treaties, and the International Law Commission’s Draft Conclusions on the Identification of Customary International Law. One important claim that I make in this chapter – and which challenges mainstream scholarship – is that the aforementioned four methods govern the interpretation of treaties, but also the interpretation of custom and general principles.
International law requires States to use specific methods to interpret their international legal obligations, including via their courts, and there are good reasons for imposing such a requirement on them. These reasons are primarily connected to the importance of lawful interpretation, but they can also be linked to the virtues of predictable, clear, and consistent legal reasoning. In this chapter, I first compare judicial interpretation to interpretation in other domains. In a second step, I briefly retrace the history of interpretative methods in domestic and international law, and I discuss the relationship between domestic and international methods. I then provide three arguments for having mandatory interpretative methods in domestic and international law: the frequent vagueness of laws, the well-known ‘counter-majoritarian difficulty’ created by judicial review, and courts’ tremendous interpretative power. Finally, I examine and respond to three classic objections that have been raised against interpretative methods.
In this concluding section, I first restate that a corollary of States’ international legal obligations is that they must use the interpretative methods required by international law, including when States interpret these obligations via their courts. They must do so regardless of their domestic (and especially their constitutional) legal specificities. Moreover, predictable, clear, and consistent reasoning is key if these methods are to be respected. While not every case raises difficult interpretative issues, and while judges face various constraints in their activity, these are not compelling justifications for leaving things unchanged. I offer several recommendations on how to improve the Swiss case law and the practice of domestic courts in general. First, the legality and the quality of domestic rulings need to be improved. Second, given the status of domestic rulings in the sources of international law and as auxiliary means, the accessibility of domestic rulings needs to be enhanced.
In this chapter, I highlight some characteristics of the Swiss legal order that deserve emphasis for the purposes of my study. A first cluster of features pertains to the relationship between the State and international law. I then highlight a series of principles of political organization that govern Switzerland. Third, I focus on the structure, organization, and functioning of the Swiss judiciary. One methodological choice I defend in this chapter is my decision to focus on a specific institutional and domestic legal context, and on how courts in this State have decided specific cases. Indeed, refraining from looking at a particular domestic judiciary and on individual cases would make it difficult to provide a thorough, reasonably comprehensive, and nuanced account of the challenges and constraints that domestic courts face. Importantly, such an approach would neglect that international law is designed to be implemented in domestic legal orders.
In this chapter, I provide an overview of existing scholarship dealing with the interpretation of international law by domestic courts in Switzerland and other jurisdictions. A new study that analyzes and seeks to guide the practice, and that complements scholarly efforts to date, is needed for at least five reasons. First, scholarly work on domestic courts and international law primarily focuses on mapping the existing practice, rather than on the normative (legal and/or moral) principles that must or should guide it. Moreover, legal theorists and philosophers tend to neglect international law. Third, the place of domestic judicial decisions in the sources of international law is ambiguous. Fourth, scholars and courts often neglect that the fact that States must respect the interpretative methods of international law is a corollary of their international legal obligations. Finally, a comprehensive overview and evaluation of Swiss courts’ practice pertaining to international law is missing.
In this chapter, I examine the legal effect of domestic rulings in international law. I argue that this effect has both static and dynamic elements. On the one hand, and this is what I refer to as the static effect, domestic courts enable States to respect their international obligations. On the other hand, from the angle of the sources of international law, domestic judicial decisions also have what I call a dynamic effect on international law. First, and as becomes apparent when analyzing art. 38(1)(a)–(c) of the Statute of the International Court of Justice (icj), domestic rulings can collectively contribute to the formation and modification of international law. Second, from the vantage point of any domestic or international interpreter of international law, domestic judicial decisions are what I refer to as auxiliary means (or ‘subsidiary means’, pursuant to art. 38(1)(d) icj Statute) that assist her in her interpretative task.
What do lawyers – as opposed to musicians, dancers, or physicists, for example – do when they interpret? What do they mean by interpretation? In this chapter, I explain that legal interpretation is special to the extent that law is an intentional object and a practice that is normative. I also reflect upon the concept of judicial interpretation and several related terms, and I distinguish domestic judicial interpretation from other types of judicial interpretation. I then clarify the notion of interpretative method: a method is a way of doing something, and methods of legal interpretation are ways of ascertaining laws. I distinguish methods of legal interpretation from several related concepts, such as normative interpretative theories and auxiliary means. Finally, given that the present study is concerned with the interpretation of international law, I delineate what this body of law encompasses.