International courts and tribunals are increasingly asked to pass judgment on matters that are traditionally considered to fall within the domestic jurisdiction of States. Especially in the fields of human rights, investment, and trade law, international adjudicators commonly evaluate decisions of national authorities that have been made in the course of democratic procedures and public deliberation. A controversial question is whether international adjudicators should review such decisions de novo or show deference to domestic authorities. This book investigates how various international courts and tribunals have responded to this question. In addition to a comparative analysis, the book provides a normative argument, discussing whether different forms of deference are justified in international adjudication. It proposes a distinction between epistemic deference, which is based on the superior capacity of domestic authorities to make factual and technical assessments, and constitutional deference, which is based on the democratic legitimacy of domestic decision-making. The book concludes that epistemic deference is a prudent acknowledgement of the limited expertise of international adjudicators, whereas the case for constitutional deference depends on the relative power of the reviewing court vis-à-vis the domestic legal order.

International courts and tribunals are often asked to review decisions originally made by domestic decision-makers. This can often be a source of tension, as the international courts and tribunals need to judge how far to defer to the original decisions of the national bodies. As international courts and tribunals have proliferated, different courts have applied differing levels of deference to those originial decisions, which can lead to a fragmentation in international law. International courts in such positions rely on two key doctrines: the standard of review and the margin of appreciation. The standard of review establishes the extent to which national decisions relating to factual, legal, or political issues arising in the case are re-examined in the international court. The margin of appreciation is the extent to which national legislative, executive, and judicial decision-makers are allowed to reflect diversity in their interpretation of human rights obligations. The book begins by providing an overview of the margin of appreciation and standard of review, recognising that while the margin of appreciation explicitly acknowledges the existence of such deference, the standard of review does not: it is rather a procedural mechanism. It looks in-depth at how the public policy exception has been assessed by the European Court of Justice and the WTO dispute settlement bodies. It examines how the European Court of Human Rights has taken an evidence-based approach towards the margin of appreciation, as well as how it has addressed issues of hate speech. The Inter-American system is also investigated, and it is established how far deference is possible within that legal organisation. Finally, the book studies how a range of other international courts, such as the International Criminal Court, and the Law of the Sea Tribunal, have approached these two core doctrines.

This study provides a comparative analysis of judicial deference in the practice of international courts and tribunals. The descriptive part of the thesis investigates to what extent a range of international courts and tribunals have adopted structural doctrines of deference when evaluating State conduct against rules of international law. The analysis covers six permanent institutions (the International Court of Justice; the European, Inter-American and African human rights courts; the dispute settlement system of the World Trade Organization; and the International Tribunal for the Law of the Sea) as well as investment arbitration tribunals. The normative part of the thesis discusses whether international courts and tribunals should adopt a deferential standard of review when evaluating State conduct. I propose a distinction between epistemic deference, which is justified by the superior capacity of domestic authorities to make factual and technical assessments, and constitutional deference, which is based on the democratic legitimacy of domestic decision-making. I conclude that epistemic deference is a prudent acknowledgement of the limited expertise of adjudicators with regard to non-legal assessments. There is generally no need, however, for constitutional deference in international adjudication, because of the limited impact of international judicial decisions on domestic decision-making. This is different for the human rights courts, whose jurisprudence can have far-reaching implications on any field of domestic public policy, and because an effective integration of human rights in domestic legal orders requires the involvement of domestic authorities in the definition of the scope and content of human rights.

"Introduction Deference and the International Adjudication of Private Property Disputes While working as a government lawyer in 2011, a letter came into our office advising that the Philip Morris tobacco company had decided to sue Australia under a bilateral investment treaty. The company contended that Australia's tobacco plain packaging requirements breached its intellectual property rights, entitling it to billions of dollars in compensation under international law. This news was not particularly shocking to the small team of which I was part, which had been assembled within the government's Office of International Law to respond to these types of claims. The news was shocking, though, to the wider Australian community. Over the ensuing months, the community's disbelief became better-articulated in the press: How can an international tribunal sit in judgment over a measure which the Australian Parliament had decided was in the public interest after extensive scientific enquiry and public consultation? Could an international tribunal really reverse the finding of Australia's highest court that the legislation was lawful?"--

The vast majority of all international judicial decisions have been issued since 1990. This increasing activity of international courts over the past two decades is one of the most significant developments within the international law. It has repercussions on all levels of governance and has challenged received understandings of the nature and legitimacy of international courts. It was previously held that international courts are simply instruments of dispute settlement, whose activities are justified by the consent of the states that created them, and in whose name they decide. However, this understanding ignores other important judicial functions, underrates problems of legitimacy, and prevents a full assessment of how international adjudication functions, and the impact that it has demonstrably had. This book proposes a public law theory of international adjudication, which argues that international courts are multifunctional actors who exercise public authority and therefore require democratic legitimacy. It establishes this theory on the basis of three main building blocks: multifunctionality, the notion of an international public authority, and democracy. The book aims to answer the core question of the legitimacy of international adjudication: in whose name do international courts decide? It lays out the specific problem of the legitimacy of international adjudication, and reconstructs the common critiques of international courts. It develops a concept of democracy for international courts that makes it possible to constructively show how their legitimacy is derived. It argues that ultimately international courts make their decisions, even if they do not know it, in the name of the peoples and the citizens of the international community.

In human rights adjudication, courts sometimes face issues that they lack the expertise or constitutional legitimacy to resolve. One way of dealing with such issues is to 'defer', or accord a margin of appreciation, to the judgments of public authorities. This raises two important questions: what devices courts should use to exercise deference, and how deference can be made more workable for judges and predictable for litigants. Combining in-depth conceptual analysis with practice in a broad range of jurisdictions, Deference in Human Rights Adjudication answers these questions. It introduces six devices for deference (namely, the burden of proof, standard of proof, standard of review, giving of weight, choice of interpretation, and choice of remedy), analyzes how courts should choose amongst them, and proposes techniques for rendering deference practicable. The book has two distinctive features. First, it engages with the jurisprudence of six common law jurisdictions that apply a structured proportionality test in rights adjudication, namely, Canada, Hong Kong, Ireland, Israel, New Zealand, and the United Kingdom. Second, it offers guidelines for judges who wish to apply its theoretical arguments. As such, Deference in Human Rights Adjudication will enable human rights adjudication to be more principled and in line with the rule of law and separation of powers. Insightful and pioneering, this book will be an important reference for researchers, teachers, and students of constitutional theory, comparative constitutional law, and human rights law around the world. It will also assist practitioners, judges, and policymakers who have to grapple with issues of deference in adjudication.