Book Review: Weapons of Mass Migration by Kelly M. Greenhill
- Editorial Team
- Mar 16
- 4 min read
In Weapons of Mass Migration, Kelly M. Greenhill unveils a provocative argument: states and non-state actors have long used forced displacement as a strategic tool to coerce, destabilize, and extract concessions from their adversaries. Blending rigorous data analysis with gripping case studies—from Cuba’s Mariel boatlift to North Korea’s refugee diplomacy—Greenhill challenges conventional wisdom on migration, security, and power politics. Is this a missing piece in our understanding of global crises, or does it overstate intent in the chaos of displacement?
Read on to find out.
Book Review of Weapons of Mass Migration by Kelly M. Greenhill
Introduction: A Timely and Provocative Examination
Kelly M. Greenhill’s Weapons of Mass Migration: Forced Displacement, Coercion, and Foreign Policy presents a compelling and rigorously researched argument: migration crises are not simply byproducts of war, economic hardship, or climate change, but are sometimes deliberately engineered as tools of statecraft.
Greenhill coins the term "coercive engineered migration," referring to instances in which weak actors (such as smaller states or non-state actors) manipulate migration flows to exert political pressure on stronger states.
She argues that this tactic has been historically overlooked but is both prevalent and often successful in shaping international policy outcomes. The book integrates large-N statistical analysis with qualitative case studies, providing both empirical breadth and narrative depth.
Strengths: A Groundbreaking Contribution
One of the book’s greatest strengths is its ability to bridge migration studies and security studies, two fields that often remain siloed. Greenhill successfully argues that forced migration should not be understood solely through a humanitarian or economic lens but as an instrument of power politics.
Several key contributions stand out:
Systematic Empirical Analysis – Greenhill identifies over 50 cases of coercive engineered migration since the adoption of the 1951 Refugee Convention, demonstrating that this is neither an isolated nor rare phenomenon.
Case Study Depth – Through a mix of historical and contemporary examples, she examines incidents such as Cuba’s strategic use of migration during the Mariel boatlift, the role of refugees in NATO’s intervention in Kosovo, and North Korea’s manipulation of migration flows to extract economic concessions.
Policy Relevance – The book is not just an academic exercise; it offers prescriptive insights for policymakers, particularly in liberal democracies. Greenhill highlights how open societies are uniquely vulnerable to migration-driven coercion due to their commitments to human rights and transparent political processes.
Weaknesses: Assumptions and Limitations
Despite its strengths, Weapons of Mass Migration has some notable limitations:
Overemphasis on State Intentionality – While Greenhill convincingly demonstrates that some migration crises are strategically orchestrated, she at times risks overstating the intentionality behind forced displacement. Many crises emerge from complex, multi-causal processes, and the extent to which state actors actively engineer them can be difficult to quantify.
Limited Perspective on Agency – The book largely presents migrants and refugees as pawns in a strategic game between powerful actors. While this is a useful framing for international relations, it arguably downplays the agency of displaced populations, who often make strategic choices of their own rather than merely serving as instruments of state policy.
Neglect of Structural Economic and Environmental Factors – Greenhill’s argument focuses on political coercion but gives less attention to how economic globalization and climate change create the conditions for large-scale migration in the first place. A broader engagement with these structural forces would have strengthened the book’s explanatory power.
Comparison to Similar Works
Greenhill’s analysis builds on and challenges existing migration and security studies. Unlike works that primarily view migration through economic or humanitarian lenses, such as The Ethics of Refugee Policy by Matthew Gibney or The Global Migration Crisis by Myron Weiner, Weapons of Mass Migration firmly positions migration as a tool of international coercion. It also complements the work of scholars like Fiona Adamson, who has examined how non-state actors and transnational networks influence migration politics.
Compared to studies on asymmetric warfare—such as Andrew Mack’s Why Big Nations Lose Small Wars—Greenhill’s book applies a similar logic to migration: weak actors can leverage the political constraints of stronger states to achieve disproportionate influence.
Broader Implications
The book has significant implications for both academia and policy:
For Scholars – Greenhill’s framework provides a new lens through which to study migration politics, moving beyond conventional push-pull models to consider coercion as a strategic variable.
For Policymakers – The book serves as a warning to liberal democracies about their vulnerability to migration-based coercion. Greenhill suggests that more robust policy tools—ranging from diplomatic deterrence to media strategies—are needed to counter such tactics.
For Human Rights Advocates – The argument that migration can be weaponized raises difficult ethical questions about how democratic states should respond without compromising commitments to refugee protection.
Final Verdict: Who Should Read This?
Weapons of Mass Migration is a must-read for scholars of international relations, security studies, and migration policy. It is also invaluable for policymakers dealing with migration crises and national security threats. However, readers should approach the book critically, keeping in mind the broader structural forces that also drive migration.
While Greenhill’s thesis is provocative and well-supported, it is not a comprehensive explanation for all forced displacement. Nonetheless, her work provides an essential framework for understanding migration as a tool of power politics, making it an important contribution to the field.
⭐⭐⭐⭐☆ Rating: 4/5
Pros: Groundbreaking research on migration as a coercive tool, strong empirical analysis, relevant case studies, and clear policy implications.
Cons: Overemphasis on state intentionality, limited discussion of migrant agency, and insufficient engagement with structural economic and environmental factors.
Recommended For: Scholars of international relations, security studies, and migration policy; policymakers handling migration crises; human rights advocates navigating refugee protection in politically charged contexts.
To place an order: https://www.cornellpress.cornell.edu/book/9781501704369/weapons-of-mass-migration/ (No affiliate link; I'm not paid for reviews.)
