Acknowledgments

This is a book about the ways in which leaders can lose complete control over important segments of the states and empires they are purportedly in charge of, producing foreign policy outcomes they had not intended at all. Funnily enough, the process by which this book came about, to some extent, reflects this basic theoretical insight. I did not initially set out to write a largely historical book. And I did not intend to write a book focused on empire. But a historical book focused, at least in part, on empire is what I ended up with.

I came to the topic for this book as, I think, many scholars of international relations do: by reading the work of the late Robert Jervis. In what I would argue is his greatest book, System Effects, Jervis speculates in one very brief section that territorial expansion might be subject to positive feedback effects, with expansion itself helping generate the conditions that drive future instances of expansion, which, in turn, generate still further expansion, and so on.1 This 130-word section of his 300-page book began an intellectual and personal journey that would lead through various cities, libraries, university departments, academic conferences, and hundreds, if not thousands, of books, articles, and diplomatic documents.

This book has been more years in the making than I care to admit. This means, not only that I have gotten older but that I have accumulated an unusually large number of debts along the way. It began at Yale University, where I was fortunate to be a part of the department of political science. My mentors and colleagues at Yale provided much-needed constructive criticism, encouragement, support, and friendship that helped get this book off the ground. These include Dave Allison, Consuelo Amat, Jonathon Baron, Tyler Bowen, Matthew Cebul, Suparna Chaudhry, Alex Debs, Mike Goldfien, Stephen Herzog, Susan Hyde, Adria Lawrence, Jason Lyall, Guatam Nair, Will Nomikos, Maggie Peters, Lauren Pinson, Chris Price, Didac Queralt, Hari Ramesh, James Scott, Ian Shapiro, and Dana Stuster. A turning point in the book’s development occurred as the result of a series of challenging and constructive conversations with Dan Altman, Richard Maass, Dan Nexon, and, especially, Keir Lieber and Josh Shifrinson. I also spent two years in the University of California, Berkeley’s political science department, and benefited from the warm hospitality and helpful advice of Ron Hassner, Aila Matanock, and Paul Pierson. At Harvard University Kennedy School’s Belfer Center for Science and International Affairs, I had many useful exchanges on various aspects of the book with Paul Behringer, Dan Jacobs, Tyler Jost, Sean Lynn-Jones, Steve Miller, and Steve Walt. Since coming to the Elliott School at the George Washington University, I have also had many fruitful exchanges on the book with many graduate students, visitors, fellows, and faculty, including Neha Ansari, Andrew Bowen, Dani Gilbert, Alex Kirss, Kendrick Kuo, Do Young Lee, Alex Lennon, Harris Mylonas, and Jo Spear. I have also been fortunate to have some of the very best in the business read and comment on various parts and at various stages of this book, including Gary Bass, David Edelstein, Tanisha Fazal, Eugene Gholz, Stacie Goddard, Kyle Haynes, Lindsay Hundley, Min Kim, Sarah Kreps, Matthew Kroenig, Melissa Lee, Sojeong Lee, Paul MacDonald, John Mearsheimer, Rachel Metz, Asfandyar Mir, Didac Queralt, Sebastian Rosato, Madison Schramm, John Schuessler, Travis Sharp, William Spaniel, Andrew Szarejko, and Dani Villa. Special thanks go to Mariya Grinberg and Jack Snyder, who read and commented on more versions of this manuscript, at more stages of its development, than they probably wanted to. I also owe thanks to Léa Glaezner for help checking my French translations. And I owe a great deal to Victor Cha, Alex Downes, Charlie Glaser, and Daryl Press, who have been an incredibly important part of my academic, professional, and personal development over many years.

I spent an inordinate amount of time in various libraries over the course of this book and benefited immensely from the hard-working staff at Sterling Memorial Library at Yale, Widener Library at Harvard, Gelman Library at George Washington, the Library of Congress, and the UC Berkeley library system. Various aspects of this project have also benefited from many presentations over the years, including at George Washington, Harvard, Yale, the IR Theory Colloquium (virtual), and various annual meetings of the American Political Science Association and the International Studies Association. Thanks also go to Kelly Sandefer and Beehive Mapping, who created the beautiful campaign maps that accompany the case studies in the book. I am grateful to the journal International Security for permission to use portions of my earlier article, “Push and Pull on the Periphery: Inadvertent Expansion in World Politics,” International Security 47, no. 3 (Winter 2022–23): 136–173, throughout this book. It has also been a great pleasure working with Jacqulyn Teoh and the amazing editorial staff at Cornell University Press. And I am deeply appreciative of two anonymous reviewers, who offered incredibly constructive feedback on every chapter of the book. And I would like to acknowledge Barry Posen’s truly great book Inadvertent Escalation: Conventional War and Nuclear Risks as the inspiration for this book’s title.

Tragically, two of my mentors passed away before this book was published. Frances M. Rosenbluth was a consistent source of guidance and support from my very early days in graduate school. I was drawn to Frances as a mentor because of her wide-ranging interests, the tough questions she asked, her constant reminders to keep the big picture in mind, and her incredible personal warmth. We also shared a love of Japan, its history, and its politics. She was an icon in our department at Yale and in the broader field of political science. Frances was diagnosed with an aggressive form of brain cancer and died in November 2021 at the age of 63, leaving behind her partner, Ian, and her sons, Ben, John, and Will. And Nuno P. Monteiro was a model mentor from my very first days at Yale. Challenging, dedicated, responsive, and kind—always pushing me to ask big questions but to fit the answers into article- or book-sized packages, and to dig deeper and to get to the theoretical core of whatever problem was in front of me. He had insatiable curiosity, a magnetic personality, an irrepressible sense of humor, and a rare generosity of spirit. Nuno died of a heart attack in May 2021 at the age of 50, leaving behind his wife Audrey, and his children Sebastian and Ava. I have dedicated this book to his memory.

The most important thanks go to my family: my parents-in-law, Kyong-ja and Adam; my siblings, Em and Ben; my sister-in-law, Jen; my nieces and nephews, Victoria, Charlotte, Joey, and Charlie; and my parents, Carol and Duncan. Thank you for a lifetime of unconditional love, support, and understanding. The other result of having spent so many years on this book is that my life has changed dramatically in the meantime: I got married and had two kids along the way. Our kids—Murphy and Perry—themselves reflect the academic journey we have been on, being born in Berkeley, CA, and in Cambridge, MA (respectively), a mere 360-days apart. Their curiosity, energy, humor, passion, and love are a constant and much-needed reminder of what is really important in life—and what is not. And my most important thanks go to my partner, Babs. For the late-night pep talks, for your patience during all the inane discussions of international relations theory, research design, and imperial Japanese history and for all of the support, encouragement, understanding, laughter, and love—I cannot thank you enough. I do not think I would have gotten through it without you.