Why, to what extent, and under what conditions are states more or less likely to comply with international law? No overarching state compels compliance. Compared to domestic law, the international institutional context is thin; courts and tribunals are limited in their jurisdiction and relatively uncoordinated. International law, moreover, is plagued by ambiguity. Treaties may be the most certain source of international law rules because they are in writing, but the language of treaties is not always clear and can be purposefully vague, giving states discretion in applying them. Non-treaty norms are even more subject to ambiguity. Why, indeed, should states ever comply? Yet they seem to, much of the time. How do we explain this behavior?

Chapter Six looks at the role of international law in the Trump administration State Department. Former policymakers gave their opinion on the extent of the effect of the Trump administration on State Department policymaking and discussed potential long-term effects. The Trump administration generally displayed a negative view toward international law, institutions, and agreements, as evidenced by its words and in its actions, a view at odds with the prevailing State Department culture. More significantly, the Trump administration took unusual steps to stifle dissent within the State Department. Former officials expressed a range of perceptions regarding the Trump administration’s effect on the State Department. A minority believed that the administration’s views and actions significantly affected attitudes and practices within the Department regarding international law and institutions. The majority believed that effects on attitudes were more likely to be felt at the policy-decision level, rather than at the lower, policy development level. That is, attitudes among rank-and-file and career State Department officials probably remained unchanged and were likely to “bounce back” after the 2020 election. Nevertheless, a reprise of the Trump administration, or a similar administration, could ultimately affect not only practices at the State Department but attitudes among officials as well.

This book is about three things. First, it explores whether, why, and how states comply with international law, focusing on the United States and the factors that affect state calculations. Second, it examines the culture, structure, and processes of the State Department and their effect on the role of international law considerations in shaping State Department decision-making. Finally, it investigates the effect of the Trump administration and its views about international law on the culture and processes of the State Department, as well as the likely effect of a similar administration in the future. To help address these questions, seventy-seven high-level former State Department officials were interviewed, as well as a handful of former high-level attorneys in the Office of the Legal Adviser.

Chapter Two summarizes the compliance literature on international relations and international law, addressing both theoretical and empirical work. This literature can be divided into two groups: The first group explores why states comply with international law and is generally associated with the primary schools of international relations theory. The study may confirm or illustrate the applicability of aspects of one or more of these theories, although that is not necessary for it to be valuable in illuminating the motivations that affect policymakers and states. The second group within the compliance literature examines more closely how states comply at the domestic level and focuses on domestic policymaking within the United States government. In this regard, the chapter concentrates on two similar normative and process-oriented approaches. The first, the international legal process approach, is drawn from international legal scholarship; the second is primarily drawn from constructivist international relations theory, and was developed primarily by Wayne Sandholtz and Christopher Whytock, among others. Both approaches emphasize the role of internalized norms and the importance of process and organizational structure in decision-making. They are, accordingly, helpful in understanding the effect of legal norms, lawyers, and process in State Department decision-making.

Chapter Three explores the views of former officials regarding compliance by states with international law. Almost all former officials believed that international law constrains state behavior, at least to some extent, and that states comply with international law much of the time. The top positive factors favoring compliance, as revealed by frequency counts, were reputational concerns; state interest in a stable legal and institutional system; reciprocity, or the prospect of retaliation; ethical considerations, including ethical values underlying international law rules and respect for the rule of law; idiosyncratic factors, including the history and culture of states; and benefits flowing from participation in specific regimes. The significant role of ethical factors gives a boost to normative theories about compliance. The role of systemic interests illustrates the benefits of a multilateral, institutional, and rule-based system. Among the factors militating against compliance, the dominant factor was state interest. Many former officials suggested that decisions about compliance involve a cost–benefit assessment, a consideration of many factors including international law. The chapter concludes by considering the former officials’ perceptions about the reasons that states outside of the United States take into consideration regarding compliance with international law.

Chapter Four focuses on US compliance with international law. The perception of former officials was that US compliance with international law was robust. When asked about the reasons that the United States complies or does not comply with international law, the former officials’ responses tracked many of the factors they listed for states in general. The chapter then explores the interplay between law and policy, exploring how policymakers balance these competing concerns. Former officials were clear that while international law was generally followed, it was not always dispositive. Legal issues were considered as one factor among a variety of factors, essentially involving a cost–benefit analysis. The salient considerations driving compliance or noncompliance, as revealed in the interviews, appeared to be the nature of the national interest or policy at stake; the nature and significance of the international legal rule involved ethical considerations; the views of allies; the ambiguity or precision of the legal obligation; and the weight of domestic political and bureaucratic concerns. The chapter next examines factors that may affect policymaker perceptions, including party affiliation, and concludes with a description of instances where the United States either bent international law or complied scrupulously.

Chapter Five examines the role of international law in State Department policymaking. It describes the formal and informal decision-making processes within the State Department, focusing on the influential role of the Legal Adviser and the Legal Adviser’s Office. The chapter then examines closely the weight given by policymakers to legal advice and the nature of the interaction between policymakers and lawyers. Policymakers, at least at higher levels, generally have final decision-making authority, but the views of the Legal Adviser’s Office can be determinative in the relatively rare instances when the lawyers deem a course of action conclusively illegal. Otherwise, the lawyers’ advice is influential, but its weight may vary depending on the circumstances, including the nature of the national interest involved. Many former officials indicated that the development of policy was often a collaborative and constructive process. The lawyers were usually willing to work with policymakers, and they were often willing to find alternative courses of action within the law, though they would not usually budge on an interpretation of the law. Some former officials indicated that their relationship involved greater contestation, resembling a negotiation. When international law conflicted with significant policy interests, policymakers could sometimes seek to overcome those obstacles.