"The Evolutionary Roots of War and Peace," Journal of Strategic Studies (forthcoming, online first), with Richard W. Wrangham

When did war and peace first emerge in the human lineage? Are they deep-rooted in our evolutionary past or are they recent cultural inventions? To tackle this question, this article integrates insights from evolutionary anthropology into the field of Strategic studies. Having first introduced two comparative techniques—cladistics and ethnographic analogy—it compares the patterns of group interaction of humans and of their closest relatives, chimpanzees and bonobos, so as to infer whether such patterns are a common trait that the three primate species inherited from their last common ancestor or, instead, a uniquely human feature. It shows that the propensity for intergroup conflict is an ancestral trait that we inherited from our chimpanzee-like ancestor, while the propensity for peaceful group interactions emerged in the human lineage after the divergence from the lineage of our primate cousins. In simpler terms, we inherited war from our chimpanzee-like ancestor, while peace is a uniquely human evolutionary innovation. The article makes three key contributions to Strategic studies. First, it explores the question of when and why war and peace emerged in the human lineage, thus addressing fundamental questions about the origins and causes of war and peace. Second, it challenges oversimplified notions of ‘human nature’, offering a more nuanced understanding of human group interactions and relationships. Third, it promotes interdisciplinary research to tackle long-standing questions about the origins and changing character of war and peace, introducing new concepts and methods while broadening the field’s empirical and temporal scope prior to recorded history and state-centric analyses. By examining the evolutionary roots of war and peace through a cross-disciplinary perspective, this article offers a deeper understanding of the biological and cultural factors that have shaped the human behavioural repertoire over the course of our evolutionary history, thus laying the foundations for the persistence of both war and peace up to the present.
"The Origins of War: A Global Archaeological Review," Human Nature, 35(3), 2024, pp. 225-288
 
How old is war? Is it a deep-seated propensity in the human species or is it a recent cultural invention? This article investigates the archaeological evidence for prehistoric war across world regions by probing two competing hypotheses. The “deep roots” thesis asserts that war is an evolved adaptation that humans inherited from their common ancestor with chimpanzees, from which they split around seven million years ago, and that persisted throughout prehistory, encompassing both nomadic and sedentary hunter-gatherer societies. In contrast, the “shallow roots” viewpoint posits that peaceful intergroup relations are ancestral in humans, suggesting that war emerged only recently with the development of sedentary, hierarchical, and densely populated societies, prompted by the agricultural revolution ~12,000–10,000 years ago. To ascertain which position is best supported by the available empirical evidence, this article reviews the prehistoric archaeological record for both interpersonal and intergroup conflict across world regions, following an approximate chronological sequence from the emergence of humans in Africa to their dispersal out of Africa in the Near East, Europe, Australia, Northeast Asia, and the Americas. This worldwide analysis of the archaeological record lends partial support to both positions, but neither the “deep roots” nor the “shallow roots” argument is fully vindicated. Intergroup relations among prehistoric hunter-gatherers were marked neither by relentless war nor by unceasingly peaceful interactions. What emerges from the archaeological record is that, while lethal violence has deep roots in the Homo lineage, prehistoric group interactions—ranging from peaceful cooperation to conflict—exhibited considerable plasticity and variability, both over time and across world regions, which constitutes the true evolutionary puzzle.
"Foreign Policy Before the State: Diplomatic Practices in Prehistory," Diplomacy & Statecraft (forthcoming, July 2025)

This paper challenges the traditional narrative linking the advent of diplomacy to the emergence of States, exploring the largely overlooked diplomatic practices in prehistory. Through a comprehensive analysis of archeological evidence and ethnographic analogies, the study reveals a sophisticated diplomatic repertoire predating the earliest states. Pleistocene nomadic communities engaged in long-distance peaceful trade and developed elaborate diplomatic practices, including messenger use, conflict resolution, truce- and peace-making, deterrence signaling, alliance formation, and espionage. Contrary to common belief, diplomacy appears as an intrinsic part of human social interactions during prehistory, emerging long before the advent of sedentary civilizations and state societies. The paper not only revisits the temporal origins of diplomacy but also opens promising avenues for future research.
 
"Janus faced: The Co-Evolution of War and Peace in the Human Species," Evolutionary Anthropology, 2024, e22027

The human species presents a paradox. No other species possesses the propensity to carry out coalitionary lethal attacks on adult conspecifics coupled with the inclination to establish peaceful relations with genetically unrelated groups. What explains this seemingly contradictory feature? Existing perspectives, the “deep roots” and “shallow roots” of war theses, fail to capture the plasticity of human intergroup behaviors, spanning from peaceful cooperation to warfare. By contrast, this article argues that peace and war have both deep roots, and they co‐evolved through an incremental process over several million years. On the one hand, humans inherited the propensity for coalitionary violence from their chimpanzee‐like ancestor. Specifically, having first inherited the skills to engage in cooperative hunting, they gradually repurposed such capacity to execute coalitionary killings of adult conspecifics and subsequently enhanced it through technological innovations like the use of weapons. On the other hand, they underwent a process cumulative cultural evolution and, subsequently, of self‐domestication which led to heightened cooperative communication and increased prosocial behavior within and between groups. The combination of these two biocultural evolutionary processes—coupled with feedback loop effects between self‐domestication and Pleistocene environmental variability—considerably broadened the human intergroup behavioral repertoire, thereby producing the distinctive combination of conflictual and peaceful intergroup relations that characterizes our species. To substantiate this argument, the article synthesizes and integrates the findings from a variety of disciplines, leveraging evidence from evolutionary anthropology, primatology, archaeology, paleo‐genetics, and paleo‐climatology.
"Illusions of Autonomy: Why Europe Cannot Provide for Its Security if the United States Pulls Back," International Security, Vol. 45, No. 4 (Spring 2021), pp. 7–43, with Stephen G. Brooks
--- See the supporting data and charts in the article's Online Appendix.
--- Listen to my talk on this article at the University of Oxford's Changing Character of War Center
--- Listen to my discussion of this article in the War & Diplomacy Podcast

Europe’s security landscape has changed dramatically in the past decade. Russia is much stronger militarily and more assertive, territorial revisionism has returned to the continent, America’s highly polarized political environment has created great doubts about the long-term reliability of its security commitment, and the European desire to pursue strategic autonomy is the strongest it has ever been. This raises an important counterfactual question: in the event of a complete US pullback from the continent, how strong are the constraints on Europe developing an adequate autonomous defense? Although a full US pullback from Europe is hard to fathom in the short-term, it is hardly a far-fetched scenario for the longer term. Carefully considering this counterfactual is the best way to gauge the likelihood that Europe truly could go its own way in defense, which has great relevance for a range of important policy issues on both sides of the Atlantic.  Moreover, this counterfactual has central importance for the ongoing U.S. grand strategy debate in light of the prominent theoretical argument from American ‘restraint’ scholars that Europe can easily defend itself. Evaluating this counterfactual requires a careful examination of the historical evolution as well as the current and likely future state of European interests and defense capacity. Our analysis shows that any effort to achieve European strategic autonomy will be fundamentally hampered by two mutually reinforcing constraints: ‘strategic cacophony’, namely profound, continent-wide divergences across all the domains of national defense policies, most notably threat perceptions, as well as severe military capacity shortfalls that will take a long time to close. As a result, Europeans are highly unlikely to effectively come together in the field of defense anytime soon even if the US were to fully withdraw from the continent.
"Pulled East: The Rise of China, Europe and French Security Policy in the Asia-Pacific," Journal of Strategic Studies, 46(6–7) (2021), pp. 1245–1286.
See the Online Appendix France's Military Presence and Naval Deployments in the Asia-Pacific.

This article delivers the first post-Cold War history of how France—the European powers with the largest political-military footprint in the Asia-Pacific—has responded to the national security challenges posed by the rise of China. Based upon a unique body of primary sources (80 interviews conducted in Europe, the Asia-Pacific and the United States; declassified archival documents; and leaked diplomatic cables), it shows that China’s growing assertiveness after 2009, and national policymakers’ perceptions thereof, have been the key driver of change in French security policy in the Asia-Pacific, pulling France strategically into the Asia-Pacific. Specifically, rising threat perceptions of China’s rise—coupled with steadily rising regional economic interests—have led Paris to forge a cohesive policy framework, the Indo-Pacific strategy, and to bolster the political-military dimension of its regional presence. By investigating this strategically crucial yet neglected dimension of French and European security policies, and by leveraging a unique body of primary written and oral sources, this study fills an important gap in the scholarly literature on both European and Asia-Pacific security dynamics. The findings of this article also shed new light on the political and military assets that France can bring to bear in the formulation of a common EU security policy toward the Asia-Pacific and on the implications thereof for the prospect of a transatlantic strategy vis-à-vis China.
"Covert Balancing: Great Powers, Secondary States and U.S. Balancing Strategies against China," International Affairs, Vol. 82, No. 2 (2021), pp. 463-481, with Luis Simón

The influence of secondary states on the balancing strategies of great powers remains largely under-estimated in the International Relations(IR) literature. We posit that secondary state preferences play a key enabling or constraining role in shaping the balancing choices of great powers, and focus specifically on what secondary state hedging entails for an established great power’s balancing strategy. We argue that when secondary states adopt a hedging strategy established great powers are incentivized to engage in what we call “covert balancing”. Covert balancing occurs when an established great power conceals its security cooperation with a secondary state beneath a cover that is seemingly unrelated to balancing a rising great power, thus working around the secondary state’s hedging strategy while at the same time helping generate a latent capacity to balance. Building upon a broad range of elite interviews conducted in Washington D.C., we probe our argument by examining U.S. balancing strategy against China in the Asia-Pacific.
"Europe Cannot Defend Itself: The Challenge of Pooling Military Power," Survival, Vol. 63, No. 1 (2021), pp. 33-40, with Stephen G. Brooks 
(Part of the special forum on Barry Posen’s article ‘Europe Can Defend Itself’; see the video of my conversation with Barry Posen and Bastian Giegerich, based on this special forum)

Detailed examinations of Europe’s autonomous defence capacity have great value for addressing a series of policy questions on European security as well as for advancing the ongoing scholarly debate over US grand strategy. The existing literature features a wide range of articles on what European ‘strategic autonomy’ is or should be, but there has been a dearth of research on what specifically is required for Europe to autonomously defend itself in a potential conflict with Russia. Accordingly, Barry Posen’s article ‘Europe Can Defend Itself’ is a crucial contribution. Yet, see no empirical basis for accepting Posen’s conclusion that ‘as far as conventional defence is concerned, European defence autonomy is not an unachievable and unaffordable goal. Indeed, it is within reach." There are many reasons for our scepticism, including persistently diverging threat perceptions and strategic priorities across Europe as well as severe military capacity shortfalls that will take a long time to close. Here, we will focus just on one specific issue: Europe’s inability to pool and effectively employ military power.
“Nodal Defence: the Changing Structure of U.S. Alliance Systems in Europe and East Asia,” Journal of Strategic Studies, Vol. 44, No. 3 (2021), pp. 360-388 (with Luis Simón and Alexander Lanoszka)

Scholars and pundits alike continue to portray the U.S.-led regional alliance systems in Europe and East Asia in stark, dichotomous terms. Whereas the North Atlantic Treaty Organization is the standard model of multilateralism, the U.S.-led system of bilateral alliances in East Asia is the archetypal ‘hub-and-spokes’ structure in which different allies (the spokes) enjoy deep bilateral strategic ties with Washington (the hub) but not with each other. We argue that these common depictions of U.S.-led alliance systems are obsolete. Instead, we show that what we label ‘nodal defence’ – a hybrid category that combines overlapping bilateral, minilateral and multilateral initiatives – better captures how the U.S.-led alliance systems in Europe and East Asia operate today. Specifically, nodal defence is a hybrid alliance system in which allies are connected through variable geometries of defence cooperation that are organized around specific functional roles so as to tackle different threats. To show how nodal defence is an emerging central feature of the U.S.-led regional alliance systems, we conduct an original cross-regional comparison of how these alliance systems work, drawing on elite interviews, official documents, and secondary literature.
"Networking Hegemony: Alliance Dynamics in East Asia," International Politics, Vol. 57, No. 2 (2020), pp. 131-149, in the homonymous Special Issue (co-edited with Matteo Dian)

This Special Issue aims to explain the transition from the Cold War US-led system of exclusive bilateral alliances in East Asia (or “hub-and-spokes” system) into a “networked security architecture”, i.e. a network of interwoven bilateral, minilateral and multilateral defence arrangements between the US and its regional allies and partners, and that also partly includes China. Drawing from the English School of International Relations, it challenges dominant Structural Realist explanations which interpret such development as a form of external balancing against a revisionist China. By contrast, this Special Issue submits that China’s selective contestation of the US-led hegemonic order in East Asia has sparked a renegotiation of such order among regional powers, which has resulted in the restructuring of the underlying alliances and defence partnerships into a networked security architecture. Speciically, regional powers have sought to broaden the composition of the US-led hegemonic order in East Asia—by diversifying the range of defence ties between US allies and partners, but also by seeking to include the PRC in it. Thereby, rather than merely balancing the People’s Republic of China, they have sought to channel the trajectory of China’s rise within this hegemonic order through a mixture of resistance and accommodation. This introductory paper develops the theoretical framework and central argument of the Special Issue.
“Shaping China’s Rise: The Reordering of U.S. Alliances and Defense Partnerships in East Asia,” International Politics, Vol. 57, No. 2 (2020), pp. 166-184, in the Special Issue Networking Hegemony: Alliance Dynamics in East Asia

The U.S.-led system of alliances and defence partnerships in East Asia has undergone profound change since the end of the Cold War. The co-called ‘hub-and-spokes’ system of bilateral alliances has been gradually supplemented by a ‘networked security architecture’—a network of interwoven bilateral, minilateral and multilateral defence arrangements between the U.S. and its regional allies and partners, and in which China is also included through a variety of cooperation channels. This paper shows that, from Washington’s perspective, the networked security architecture is not merely a means to externally balance a revisionist China, as Structural Realist analyses contend. Rather, the U.S. has sought to broaden the composition of the U.S.-led hegemonic order in East Asia by diversifying the range of defence ties with and amongst its allies and partners, but also by seeking to include the PRC in it. Thereby, Washington aims to channel and shape the trajectory of China’s rise within the U.S.-led hegemonic order, from a position of pre-eminence, through a mixture of negative and positive incentives (resistance and accommodation) with the ultimate goal of upholding the existing hegemonic order. To empirically substantiate this argument, the paper relies on a large body of elite interviews with senior U.S. policymakers in the White House, the State Deparmtent and the Pentagon.
“Upside Down: Reframing European Defence Studies,” Cooperation and Conflict, Vol. 54, No. 3 (2019), pp. 378–406 (with Marco Wyss)

Since the end of the Cold War, the study of European defence has been dominated by a ‘Common Security and Defence Policy (CSDP)-centric’ approach, while largely neglecting the comparative analysis of national defence policies. This article makes a conceptual and empirical case for turning the dominant research prism of European defence studies upside down by returning the analytical precedence to the national level. This approach privileges the comparative analysis of national defence policies and armed forces, before focusing on the trans-/supra-national level. The case for this analytical turn is made in three steps. Firstly, it addresses the different historical stages in European defence integration and the transformation of national armed forces and thereby brings to light the recent renationalization of defence in Europe. Secondly, it questions the predominance of the CSDP in the scholarly literature on European defence. Finally, it seeks to demonstrate the fruitfulness of such a démarche by empirically substantiating common patterns and intra-European divergences in the evolution of national defence policies and armed forces since the end of the Cold War. After having shown the need and added benefit of turning the analytical lense of European defence studies on its head, the conclusion suggests future avenues of research on national defence policies and armed forces in Europe.
“The Strategist’s Dilemma: Global Dynamic Density and the Making of US ‘China Policy’,” European Journal of International Security, Vol. 3, No. 2 (2017), pp. 211-234 (lead author, with Benjamin Jensen)

Combining the English School of International Relations and the study of grand strategy decision-making processes, this article investigates how dynamic density – growing volume, velocity, and diversity of interactions within international society – alters states’ strategy formation processes. By contrasting the perspectives of structural realism and the English School on the role of dynamic density in world politics, the piece illustrates the strategist’s dilemma: as global dynamic density in the international society increases, the ability of great powers to formulate coherent grand strategies and policies potentially decreases. Specifically, it contends that growing global dynamic density generates processual and substantive fragmentation in strategy formation. Building on a large body of elite interviews, US policy toward China – and the so-called US ‘rebalance’ to Asia – is used as a probability probe of the central idea of the strategist’s dilemma. In conclusion, we contrast our findings with complex interdependence theory and examine their implications for ‘great power management’ (GPM) as a primary institution of international society. We argue that, by generating processual and substantive fragmentation in strategy formation, global dynamic density complicates GPM by hindering the capacity of great powers to manage and calibrate the competitive and cooperative dynamics at play in a bilateral relationship.
“Arming China: Major Powers’ Arms Transfers to the People’s Republic of China,” Journal of Strategic Studies, Vol. 41, No. 6 (2018), pp. 850-886 (lead author, with Lucie Béraud-Sudreau, Paul Holtom, Matthew Uttley)

The rise of China has been fuelled by a massive military modernisation programme relying, in large part, on the acquisition of foreign military equipment. The question of how the world’s major powers define their arms transfer policies towards China is therefore crucially important. This article makes two original contributions. First, drawing on neoclassical realism, it proposes an explanatory framework integrating international and domestic factors to explain variations in major powers’ arms transfers. Second, based on a large body of elite interviews and diplomatic cables, it offers the first comprehensive comparison of American, British, French and Russian arms transfer policies towards China since the end of the Cold War.
“Balancing Conflicting Security Interests: US Defence Exports to China in the Last Decade of the Cold War,” Journal of Cold War Studies, Vol. 17, No. 1 (2015), pp. 4-40

This article discusses the rationale and evolution of U.S. defense exports to the People's Republic of China (PRC) during the final decade of the Cold War. The article is based on a large body of primary sources, including newly declassified documents, congressional hearings, and interviews with key officials. It shows that, contrary to what is often assumed in the literature, U.S. officials’ assessments of the optimal degree of defense cooperation with Beijing did not result solely from the objective of using the “China card” against the Soviet Union. A broader range of national security considerations shaped U.S. military cooperation with the PRC, including a desire not to enhance China's offensive capabilities vis-à-vis the United States and its Asia-Pacific friends and allies, the impact of defense transfers to China on U.S.-Soviet diplomatic relations, and the willingness of China to cooperate on nuclear proliferation. Faced with conflicting national security interests, the United States had to make delicate trade-offs in its military relationship with the PRC.
“Actors, Coalitions and the Making of Foreign Security Policy: US Strategic Trade with the People’s Republic of China,” International Relations of the Asia Pacific, Vol 15, No. 3 (2015), pp. 433-475

This paper examines how the United States has balanced conflicting national security and economic interests in the making of US export control policy on defense-related technology toward China in the post-Cold War era. Relying upon a large body of primary sources (including 170 interviews), it seeks to contribute to the understanding of this strategically sensitive yet neglected area of Sino–American relations. It is shown that, as a consequence of the erosion of the US capacity to control the diffusion of defense-related technology to China in the post-Cold War era, a growing set of actors within the United States has reassessed the security/economic calculus in Washington's relationship with Beijing. Specifically, this coalition advocates the streamlining of export controls to sustain the defense and technological industrial base and thereby maintain American military/technological preeminence vis-à-vis a rising China.
“Post-Cold War Trends in the European Defence Industry: Implications for Transatlantic Industrial Relations,” Journal of Contemporary European Studies, Vol. 18, No. 1 (2010), pp. 63-77

Since the end of the Cold War, Europe's defence industry continues to consolidate, and this process has resulted in significant restructuring across European borders. Having examined the post-Cold War changing economic and technological conditions in the armaments market, the article investigates how the interplay between the defence industries' strategies in facing this new environment and the EU initiatives in the security realm has transformed Europe's defence industrial base. The implications of these changes for transatlantic industrial relations are then analysed in the space sector.
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“Reflections on Politics, Strategy and Norms in Outer Space,” Defence & Security Analysis, Vol. 25, No. 1 (2009), pp. 89-98 [Critical Comment]

This Critical Comment reflects on US space policy predicated on Everett Dolman’s book Astropolitik: Classical Geopolitics in the Space Age, which discusses American grand strategy in outer space. The book explains how the physical attributes of outer space and the characteristics of space systems shape the application of space power. 

Peer-Reviewed Articles in French
“L’Asie-Pacifique dans le débat stratégique américain : Obama, Trump et la montée en puissance de la Chine,” [Asia-Pacific in the Contemporary US Strategic Debate: Obama, Trump and the Rise of China], Politique internationale, No. 33 (2019), pp. 43-68
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“Enjeux stratégiques et économiques des politiques d’exportation d’armement: une comparaison franco-américaine,” Revue internationale de politique comparée, Vol. 23, No. 1 (2016), pp. 57-84 (with Lucie Béraud-Sudreau)