The rule of law is measured in many ways: through surveys of expert opinions and public perceptions, institutional proxies, and assessment of political, legislative, and judicial events bearing on the rule of law. This essay argues that systematic interviewing of judges and other legal elites belongs in the empirical toolkit of rule-of-law scholarship. The methodological literature in political science has solidified best practices for interviewing and has demonstrated that interviews can be a rigorous method for eliciting information when designed with care around selection, design, and reporting. Interviews also draw on comparative advantages that legal scholars possess, including access, shared professional vocabulary about substance and procedure, and the capacity to read silence. Interviews offer empirical access to the inside view of the actors whose decisions other measurement approaches capture only at a distance. We share these insights and apply them to rule of law measurement. To motivate these claims with empirical evidence, and illustrate best practices, we draw on 24 on-the-record interviews conducted in 2024 with sitting members of the Court of Justice of the European Union (CJEU).

We seek to open the black box of the courts, to study what judges do and how they do it. To do so, we examine the everyday practices of international judges, with particular focus on practices associated with judicial decision making. This practice turn can enrich our understanding of judicial decision-making practices, including processes of deliberation, collective decision-making, and opinion drafting, that in turn shape the meaning and significance of legal outcomes. To spark interest in practice-oriented research, this article introduces practice theory, a sociological approach that has that has been influential across the social sciences, as well as our conception of international judicial practices. We then demonstrate how practice theory can be applied to judicial practices by analyzing one of the most striking differences in judicial practices between the European courts, namely the use (or non-use) of separate opinions.

This chapter examines the complex and often ambivalent relationship between feminist theory and the mainstreams of international relations (IR) and international law (IL). It highlights two core dimensions of analysis: the dichotomy between theory and practice, and the disciplinary divide between IR and IL. Along both dimensions, feminists face choices and trade-offs between a critical or outsider approach, as opposed to an engaged or insider approach. With respect to theory, the chapter analyzes the troubled engagements of feminist scholars with mainstream IR and IL paradigms, emphasizing barriers such as epistemological differences and fears of co-optation and the costs and benefits to feminists of engaging mainstream scholarship. With respect to practice, the chapter examines attempts to mainstream gender in international organizations and to insert gender into international criminal, human rights, and security law, noting both the successes and the compromises and costs associated with these insider strategies. The chapter concludes by addressing the trade-offs inherent in feminist engagement with mainstream theory and practice, offering a critical assessment of whether such efforts are ‘worth it’ in advancing gender equity within the structures of academic scholarship and global governance.

This chapter surveys seven decades of theorizing about European Union policy-making and policy processes. It begins with a discussion of theories of European integration, including neo-functionalism, intergovernmentalism, liberal intergovernmentalism, institutionalism, constructivism, and postfunctionalism. It then considers the increasing number of studies that approach the EU through the lenses of comparative politics and comparative public policy, focusing on the federal or quasi-federal aspects of the EU and its legislative, executive, and judicial politics. It finally explores the vertical and horizontal separation of powers in the EU and concludes by looking at the ‘governance approach’ to the EU, with emphasis on multi-level governance and EU policy networks, Europeanization, and the question of the EU’s democratic deficit.

This chapter examines trends in European Union policy-making during times of multiple, overlapping challenges. It first considers the main trends in EU policy-making that emerge from policy case studies, including experimentation with new modes of policy-making, often in conjunction with more established modes, leading to hybridization; renegotiation of the role of the member states (and their domestic institutions) in the EU policy process; and the erosion of traditional boundaries between internal and external policies. The chapter explores how the EU has responded to the challenges of Brexit, the politicization of the Union, geopolitical upheaval, and the shock of the Covid-19 pandemic.

The European Union represents a remarkable, ongoing experiment in the collective governance of a multinational continent of nearly 450 million citizens and 27 member states. The key aim of this volume is to understand the processes that produce EU policies: that is, the decisions (or non-decisions) by EU public authorities facing choices between alternative courses of public action. We do not advance any single theory of EU policy-making, although we do draw extensively on theories of European integration, international cooperation, comparative politics, and contemporary governance; and we identify five ‘policy modes’ operating across the 15 case study chapters in the volume. This chapter introduces the volume by summarizing our collective approach to understanding policy-making in the EU, identifying the significant developments that have impacted EU policy-making since the seventh edition of this volume, and previewing the case studies and their central findings.

Abstract Former US President Donald Trump represents the most significant ‘change agent’ in international law in recent decades, withdrawing from and attacking a variety of international agreements. This chapter analyses Trump as a change agent, exploring the nature of his policies and their legacies in the Biden administration. With respect to the former, the chapter argues that Trump represents a ‘hostile’ change agent, seeking to change not the rules of law, but rather the rule of law, replacing multilateral institutions with power-based bargaining. With respect to legacies, it argues that Trump’s attacks effected important changes that became path-dependent, reversible only at a cost to his successor. It explores these arguments through a comparative case study of Trump’s policies in four areas of international trade law: (a) renegotiation of North American Free Trade Agreement (NAFTA); (b) withdrawal from the Trans Pacific Partnership; (c) non-compliance with World Trade Organization (WTO) rules; and (d) paralysis of the WTO Appellate Body.

Separate opinions are common across many international courts and tribunals, yet their great variety and their impacts on judicial independence, judicial legitimacy, and the development of law are poorly understood. This paper provides a synoptic overview of separate opinions in international adjudication and arbitration by analyzing more than a century of debates over, and practice regarding, these judicial writings. To do so, it examines enduring normative debates over the desirability and impact of separate opinions and leading theories regarding the motivations for and frequency of separate opinions. It then explores the use and impact of separate opinions at the International Court of Justice, International Tribunal for the Law of the Sea, regional human rights courts, WTO dispute settlement, regional integration courts, international criminal courts, arbitration tribunals, and human rights treaty bodies.

The 21st century has witnessed a backlash against many international courts (ICs). Studies of IC backlash have generally taken an optimistic tack, noting that most courts have survived backlash intact or-in the case of the paralyzed Appellate Body (AB) of the World Trade Organization (WTO)-are likely to do so after a temporary period of slumber. In this context, this paper analyzes the United States' successful effort to paralyze the AB, deriving lessons from this deviant case of backlash against one of the world's most active and independent ICs. Undertaken in the context of the "Reversing Delegation" research project, this account is organized in five parts. First, I demonstrate that the creation of the AB was a classic instance of delegation of dispute-settlement power, and that the AB quickly emerged as an active agent of trade liberalization. Second, I explore the roots of politicization, noting that dissatisfaction with AB jurisprudence preceded the Trump administration, although Trump's delegitimation of the AB was more far-reaching than that of his predecessors. Third, I examine the administration's use of the veto power to paralyze the AB, an act of de facto de-delegation. Fourth, I assess the pushback from the many other WTO members that sought to defend the AB, showing how they failed to blunt the US campaign. Fifth, I analyze the remarkably successful outcome of the US attack, and draw lessons for judicial independence and the rule of law in international politics.

The international community in the 21st century is more legalized and more judicialized than at any other period in history. Yet today’s international legal order is also fragmented, leading to concerns about the proliferation of specialized legal regimes, adjudicated by an uncoordinated assemblage of international courts and tribunals. In this volume, we and our fellow authors explore international judicial cooperation, competition, and cross-fertilization “beyond fragmentation.” Existing scholarship on international legal fragmentation, we suggest, has moved through three phases in recent decades. In the first phase, practitioners and scholars reacted with alarm to the judicial proliferation of the post-Cold War years, which they feared would create systemic problems of overlapping and contested jurisdiction, as well as conflicting and divergent interpretations of law. Following this period of “postmodern anxieties,” the new century saw the pendulum swing towards towards a second, more optimistic school of thought, which empirically identified (and normatively championed) a series of techniques whereby international judges could “manage” fragmentation through dialogue and cross-fertilization, producing convergence and unity in international law. Most recently, in the opening salvos of a third wave, skeptics have questioned the management account, pointing to the mixed motives of international judges and the limits of cross-fertilization. Building on this debate, this volume interrogates the record of cross-fertilization, cooperation, and competition among international courts and tribunals. In doing so, we address three important themes. First, we examine the phenomenon of cross-fertilization in the area of procedural law, finding that that courts do indeed learn and borrow from each other in establishing procedural rules, which show signs of convergence. Second, we examine the more complex experience of cross-fertilization in substantive international law, where we find greater variation among international courts and tribunals in their willingness to refer and defer to others. Third and finally, we investigate the agents of cross-fertilization, including not only judges but also international governmental organizations, international court registries and arbitral secretariats, member states, litigants, and counsel. Each of these actors, we suggest, possesses mixed motives, weighing their (perhaps weak) interest in the coherence of the international legal system against their (perhaps dominant) interests in their own regional or substantive legal order or values, or indeed with simply winning their current dispute. The picture that emerges is one in which international judicial cross-fertilization is both real and important, but also highly variable and asymmetric across courts and issue-areas, and likely to remain so.

This paper surveys the scholarship on the role of international law in international relations, exploring theories of international law, levels of analysis at which international law operates and has been studied, and the complex relationship of international law to the interrelated questions of order and change. The first section, “Law and Theories,” explores the ever-growing diversity of theoretical perspectives found within and across the disciplines of law and political science. The second section, “Law and Levels,” engages with the question of how we conceptualize levels of analysis with respect to the study of international law, identifying (at least) five levels of analysis in recent scholarship. In the third section, “Law and Order,” I engage with the question of how international law relates to international order, suggesting three possible answers: that law simply reflects order, that it constitutes and maintains order, and that it may actually undermine order. The fourth section, “Law and Change,” considers international law as a source of change, with the potential of creating “positive feedbacks” that prompt the “progressive development” of law – up to the point where it elicits “negative feedbacks” and “backlash.” A brief fifth section concludes by suggesting that, while scholarship on international law is arguably experiencing a golden age, the high water mark of international law in world politics may well have passed.

This chapter offers a new framework for theorizing about the roles of different types of actors who participate in processes of cross-fertilization. All of these actors have complex or mixed motives: while actors may place some value on the coherence of the international legal system, they weigh such systemic concerns against other, more immediate concerns. International judges, for example, may place value on the coherence of the international legal system, but they may place greater emphasis on the autonomy of their own specialized or regional legal order, on the normative values of that order and on their own authority within that order. Other actors, by contrast, may place little or no value on international legal coherence, but favor or oppose cross-fertilization as a function of its effect on the their likelihood of prevailing in a dispute. In a world of complex actor preferences, the process of cross-fertilization is likely to resemble, not a consensual process of management, but a constant struggle among a wide variety of actors, some of whom will champion cross-fertilization while others seek to prevent or limit it.

From its inception, international law has been closely linked to philosophy and political theory, and over time competing theoretical approaches have emerged to explain international law’s nature, form, and efficacy. Even today, we associate the most authoritative names in the discipline – whether founders such as Grotius and Vattel or more modern figures ranging from Kelsen and Lauterpacht to contemporary writers such as Chimni, Chinkin, and Koskenniemi – with specific theoretical perspectives that engage foundational questions about international law’s purpose and content.

This Article analyzes long-standing disagreements over dissent's effect on judicial legitimacy, independence, and legal doctrine by undertaking the first comparative study of dissent practices across three leading tribunals, the International Court of Justice, the European Court of Human Rights, and the European Court of Justice. Surprisingly, we find that each of the central claims in debates over dissent at international courts is mistaken. We find that the presence of dissents has little systematic impact on legitimacy; the key factor instead is patterns of dissent that suggest bias among international judges. We find that the effects of dissent on judicial independence are mediated by a third factor, namely the length and renewability of judicial terms of office. Finally, we find that dissents promote law development, but little evidence that today's dissents form the basis for future majority rulings. We then outline a research agenda to examine the impact of dissent at the larger universe of international courts.

This introduction reviews scholarship on international legal fragmentation, lays out a framework for understanding international judicial cross-fertilization, and previews the contributions and their findings. Existing scholarship on international legal fragmentation, we argue, has moved through three phases over the past several decades. In the first, legal scholars and practitioners reacted with alarm to the judicial proliferation of the post–Cold War years, which they feared would create overlapping jurisdiction and conflicting interpretations of law. Following this period, the new century saw the pendulum swing toward a second, more optimistic picture in which international courts addressed fragmentation through “management” techniques, producing unity in international law. We can detect the opening salvos of a third wave, as skeptics have questioned the management account, pointing to the mixed motives of international judges and the limits of cross-fertilization. In this volume, we build on the existing literature by theorizing the actors of cross-fertilization and their motives, and by distinguishing between procedural and substantive cross-fertilization.

Over the past several decades, it has become commonplace in both scholarly and political circles to contrast the positions of the US and the European Union EU toward the rule of international law. Critics have argued that the US had abandoned its post-war role as the champion of the international legal order, being instead characterized by a “new sovereigntism” that seeks to protect the US from unwelcome intrusions of international law into the domestic legal order. By contrast, the EU has been seen as inherently committed to the rule of law and a strong international legal order. The aim of this paper is not to attack, much less to debunk, the conventional dichotomy between a scofflaw America one the one hand and an international law-loving Europe on the other. The more limited aim of this paper, rather, is to suggest that European attitudes towards international law may be changing, and that the EU is developing a European variant of the American new sovereigntism, in which a growing number of critics – concentrated primarily, though not only, among the pro-European left and center-left – have raised fundamental procedural and substantive objections to international rules and norms, which they depict as hostile to European laws and values, and against which they champion a defiant resistance. In a growing number of areas of international law, including international trade, economic regulation, food safety, data privacy, and national security, the European center-left has moved towards a sharply critical view of international law, alternatively resisting consent to unwelcome agreements, compliance with unwelcome international judicial decisions, and internalization of international laws perceived to be in tension with domestic EU rules and rights. These changing attitudes towards international law, in turn, have been magnified and translated into policy outcomes through the EU’s “hyper-consensus” political institutions, which have created multiple veto points empowering European critics to defy and deflect the intrusion of unwelcome international legal norms, rules, and agreements.

In recent years, a variety of efforts have been made in political science to enable, encourage, or require scholars to be more open and explicit about the bases of their empirical claims and, in turn, make those claims more readily evaluable by others. While qualitative scholars have long taken an interest in making their research open, reflexive, and systematic, the recent push for overarching transparency norms and requirements has provoked serious concern within qualitative research communities and raised fundamental questions about the meaning, value, costs, and intellectual relevance of transparency for qualitative inquiry. In this Perspectives Reflection, we crystallize the central findings of a three-year deliberative process—the Qualitative Transparency Deliberations (QTD)—involving hundreds of political scientists in a broad discussion of these issues. Following an overview of the process and the key insights that emerged, we present summaries of the QTD Working Groups’ final reports. Drawing on a series of public, online conversations that unfolded at www.qualtd.net , the reports unpack transparency’s promise, practicalities, risks, and limitations in relation to different qualitative methodologies, forms of evidence, and research contexts. Taken as a whole, these reports—the full versions of which can be found in the Supplementary Materials—offer practical guidance to scholars designing and implementing qualitative research, and to editors, reviewers, and funders seeking to develop criteria of evaluation that are appropriate—as understood by relevant research communities—to the forms of inquiry being assessed. We dedicate this Reflection to the memory of our coauthor and QTD working group leader Kendra Koivu. 1