The New Haven School emerged during the era of Pax Americana in the post–Second World War period, generating a new discourse within twentieth-century international legal thought. The scholarly collaboration between Professors Myres McDougal and Harold Lasswell from 1950 to 1960 facilitated the development of this scholarship, which articulated the defining characteristics of an emerging America-led world order. Despite its significance, there remains a notable gap in international legal scholarship regarding the imperative of the New Haven School. With the exception of the forty pages dedicated to the topic by Martti Koskenniemi in his influential work The Gentle Civiliser of Nations, most leading international legal theorists have largely neglected the importance of the New Haven School. This lack of engagement may be attributed to the complexity of the foundational texts produced by its pioneers. Although extensive, these writings are often characterised by prolixity, opacity and frequent inscrutability.

Ríán Derrig has undertaken the daunting task of reconstructing the intellectual trajectories of McDougal and Lasswell that ultimately converged at New Haven. Drawing on a vast array of unpublished documents and other sources that illuminate the broader historical context, Derrig’s work, The New Haven School: American International Law, offers a compelling portrayal of American scholars and their search for a new approach to legal scholarship. It captures the vibrant intellectual currents that shaped North American thought from the 1920s to the 1960s. The foreword is written by Samuel Moyn, a prominent scholar whose work has had a significant influence on liberal approaches to international law. His affiliation with Yale University, from where the New Haven School emerged, makes him a particularly fitting choice to introduce the volume.

Derrig introduces the New Haven School as policy-oriented jurisprudence, a term coined by Lasswell in 1966. The author’s concise yet coherent analysis convinces even readers unfamiliar with the New Haven School. Rather than offering an overly lengthy examination – which could have distracted from his main task of exploring the intellectual history of two distinguished scholars – Derrig highlights key features essential to the school’s ethos, such as viewing law as an authoritative and controlling decision-making process. Additionally, Derrig notes that the New Haven School aligns with legal realism, particularly during the period when the United States emerged as a global superpower.

The first two chapters are intellectual biographies of Lasswell and McDougal, respectively. These chapters begin with formative early experiences and end with sketches of the two scholars’ writings and careers in the early 1930s, just prior to the beginning of the collaboration that shaped the rest of their intellectual lives. Especially, Lasswell’s years as a student of political science at Chicago and McDougal’s time as a Rhodes scholar at Oxford to read Roman law affirm how their legal acumen was shaped by the socio-political currents of their age.

Some may contend that Derrig’s extensive biographical information on McDougal and Lasswell is superfluous in a scholarly context. However, the detailed account of the early career progress of both scholars helps the reader to understand how their shared intellectual ideas set the path for a new scholarship. Notably, their joint ventures, such as publishing their seminal 1943 article, which emphasised reforming American legal education to produce policymakers, stemmed from their similar intellectual backgrounds. The chapter titled ‘Teaching American International Law’ reflects on their early-stage joint scholarly endeavours. Following the United States’ ascent in global governance after the decline of the traditional European concert of powers post-1945, the conventional Eurocentric approach to international law – shaped primarily by Belgian, Dutch, French and British jurists – diminished in influence. The United States’ emergence required conceptualisation within the framework of international law. In this context, the seminars organised by McDougal and Lasswell at Yale Law School served as a significant mechanism for the United States to define its position. Their major work, Jurisprudence for a Free Society: Studies in Law, Science and Policy,Footnote ¹ is thoroughly analysed by Derrig in this chapter, emphasising how their perspectives on policy-oriented jurisprudence and contextual analysis align with American values.

Among the most insightful observations highlighted by Derrig are those concerning McDougal’s and Lasswell’s efforts during the 1960s to disseminate their ideas among students at Yale Law School. Derrig illustrates vividly how many of the students who studied international law under the two scholars later became influential figures in American public life. As Derrig notes, ‘[m]any of those students later became prominent scholars, judges, government officials, and lawyers. By the late 1960s, some had begun to identify as members of a ‘New Haven School’ of international legal studies founded on the teaching of Lasswell and McDougal’ (p. 125).

In addition to biographical sketches of Lasswell and McDougal, the book offers valuable insights into McDougal’s increasingly critical attitude towards Soviet policy during the Cold War, a position shaped by his strong anti-communist convictions. For example, this work traces McDougal’s campaign to justify the legality of the US naval blockade of Cuba, in which McDougal displayed his anti-Soviet sentiments in the American Journal of International Law.Footnote ² Derrig also examines Lasswell and McDougal’s efforts to promote their approach to international law on a global scale, particularly beyond the Atlantic world. This endeavour proved challenging because of the ambivalent reception that McDougal and Lasswell encountered in Europe. McDougal’s rejection of formalism, a concept central to European rational philosophy, led to a highly critical academic reception of the scholarship of McDougal and Lasswell among strict legal-positivist circles in Europe.

McDougal and Lasswell’s New Haven project attracted sharp criticism from more traditional Anglo-American circles of international law, in particular, the publication of The Interpretation of Agreements and World Public Order: Principles of Content and Procedure,Footnote ³ a major monograph authored by McDougal, Lasswell and James C. Miller in 1967, which articulated the central tenets of their approach to international law. Derrig highlights the criticisms advanced by Herbert Briggs of Cornell University and by Gerald Fitzmaurice, both of whom dismissed the central arguments of The Interpretation of Agreements as little more than polemics.

The penultimate chapter is arguably the most compelling section of the book, as it examines McDougal’s unsuccessful attempt to defend United States interests before the International Court of Justice when he appeared as counsel for the United States in the Military and Paramilitary Activities in and against Nicaragua case. The case was brought by Nicaragua to challenge US support for the Contras, the right-wing paramilitary groups funded and backed by the United States. Derrig traces the arguments advanced by McDougal, many of which focused on procedural and jurisdictional issues, such as admissibility, rather than the substantive legal merits of the dispute. Derrig portrays the proceedings at the Peace Palace as reflecting broader questions concerning the exercise of US power in international affairs, with McDougal drawing upon principles associated with the New Haven School in an effort to justify the American position. In addition to highlighting the technical irregularities of the Nicaraguan team, McDougal’s arguments addressed fundamental issues of state security and democratic values in opposition to covert subversion. These claims exemplified the New Haven approach. However, these arguments were ultimately unsuccessful against the Nicaraguan legal team, led by Ian Brownlie, then Chichele Professor of Public International Law at the University of Oxford. This confrontation illustrated the clash between two visions of international law: the rigid formalism underpinning Brownlie’s reliance on the textual application of treaty law and McDougal’s preference for anti-formalism. Derrig observes: ‘Here was the flip side of McDougal’s conception of international law as a means of intervention in internal affairs – not all public orders were equally constitutive of the nascent world public order’ (p. 178).

In my view, the final two chapters are equally illuminating, as they capture the intellectual core of the New Haven School and its distinctive contribution to international legal thought. They demonstrate how the anti-formalism championed by the New Haven School served American interests in the late twentieth century and subsequently encouraged alternative approaches to international law, such as David Kennedy’s critical legal studies scholarship, to adopt more nuanced perspectives on the inherent tension between legal rules and politics. Derrig candidly acknowledges that the writings of McDougal and Lasswell often pose difficulties for contemporary readers owing to their dense style, extensive use of doctrinal examples and intricate analytical frameworks structured around recurring categories of values.

Given the complexity and relative obscurity of New Haven scholarship, one may reasonably ask why contemporary readers should engage with these ideas today. In the book’s concluding chapter, Derrig offers a persuasive answer to this question. He states, ‘[t]he reflexive equating of American security and interests with the security and interests of the entire world is still routinely present in a wide swathe of the field of American international law’ (p. 199).

Overall, Derrig’s book deserves recognition as a meticulously researched and intellectually engaging study of a distinctive tradition in international legal thought that has frequently been overlooked or misunderstood. Most importantly, Derrig’s comprehensive 212-page analysis clearly illustrates how the New Haven School influenced modern international legal thought. He also highlights the integration of multiple disciplines in understanding international law, ultimately rejecting legal positivism as the sole solution. The New Haven School’s greatest impact may be its introduction of a distinct approach to legal and foreign policy debate, which this book refers to as American international law. By reconstructing the intellectual development, influence and reception of the New Haven School, the book makes a significant contribution to the historiography and scholarship of international law.