Introduction

Territorial Expansion in International Relations

Inadvertent expansion is a little-explored phenomenon in the study of territorial expansion. In debates over what explains the tendency for great powers to expand territorially, answers generally focus on the gains of conquest, anarchy and the search for security, the offensive or defensive nature of technology or geography, commitment problems and the presence of “buffer states,” state institutional capacity, and the revisionist intentions of leaders.15 However, despite their great variety and value, all of these arguments share a common tendency: that of seeing expansion as a largely strategic activity, dependent upon decisions made by leaders in the capitals of powerful states. A clear example of this sort of thinking can be found in Robert Gilpin’s War and Change in World Politics, in which he argues that “a state will seek to change the system through territorial, political, and economic expansion until the marginal costs of further change are equal to or greater than the marginal benefits.”16 Another example comes from John Mearsheimer, who, in laying out his theory of offensive realism, explicitly assumes that states are “rational actors” and argues that “conquering and controlling territory” is their “paramount political objective.”17 Tanisha Fazal similarly points to the “strong incentives” states have “to take over the buffer states that lie between themselves and their opponents.”18 And Dan Altman, focusing on modern conquest, unpacks the “calculated risk” that leaders engage in when making forcible territorial gains.19 In short, a centralized and strategic conception of territorial expansion pervades much of the existing literature.

Other theories of territorial expansion de-emphasize its strategic nature, focusing instead on the biases associated with domestic political regime type, the influence of financial and capitalist elites, leader psychology, status seeking, domestic political logrolling and nationalist mythmaking, xenophobia, and a “cult of the offensive” in military doctrine and strategy.20 In these theories, the motives driving expansion render the activity less than entirely strategic or rational from the perspective of the state or empire as a whole. Yet, they still conceive of expansion to be rooted in decisions made by the leaders in the capital. For instance, Bruce Bueno de Mesquita and his coauthors argue that “leaders of small winning-coalition systems”—in effect, autocrats—will be “more inclined to seek territorial expansion” than their large winning-coalition counterparts.21 Similarly, Jeffrey Taliaferro argues that when “leaders perceive themselves as facing losses relative to their expectation level, the pursuit of relatively risky strategies in the periphery becomes more likely.”22 Thus, even many of the nonunitary and nonrational theories of territorial expansion tend to explain expansion decisions with reference to state leaders.

There are two recent exceptions to these broader trends in the literature. The first is research by Peter Krause and Ehud Eiran on territorial expansion by small nonstate groups and organizations—what they refer to as “radical flank groups.”23 Krause and Eiran argue that modern constraints on territorial expansion by states are not equally binding on nonstate actors and, in fact, can be used to their advantage. They test their arguments by focusing on Israeli settlement of the West Bank, from 1967 to the present, and find that, in fact, these radical flank groups established a majority of all settlements in this period. The second exception is research by Paul MacDonald on “autonomous expansion” in colonial empires.24 MacDonald argues that the unique governance structures of colonial empires—with chains of delegation running from the capital, to the imperial proconsul, to the local intermediary—predispose these empires to expand autonomously from metropolitan leadership. Using examples from the history of the British in India and sub-Saharan Africa, he shows that various forms of instability in these hierarchical governance structures can prompt a number of forms of autonomous expansion.

These works represent important advances in the study of inadvertent expansion, and the arguments I present in this book share theoretical affinities with them. Nonetheless, they leave several questions unanswered. For instance, Krause and Eiran’s work does not account for variation, such as when and where “radical flanks” are more or less likely to claim territory and when leaders in the capital are more or less likely to accept or reject it. MacDonald’s arguments are limited to circumstances of organized European imperialism—situations where there are formal proconsul positions as well as local imperial officials—and do not apply to inadvertent expansion observed beyond such circumstances. The theory this book presents builds on the insights of these works to better explain variation in the behaviors and decisions of actors in the periphery and the metropole not only in cases involving formal imperialism but also in those involving the extension of state territory, wartime expansion, and the like. In doing so, I offer a more comprehensive explanation of periphery-driven expansion in world politics that deepens our understanding of how great power territorial expansion occurs.

The Argument in Brief

Inadvertent expansion is territorial expansion that is planned and executed by actors on the periphery of a state or empire without the authorization of central leadership in the capital. The process of inadvertent expansion unfolds in two basic steps—“unauthorized peripheral expansion” and “subsequent central authorization.” In the first step, state or nonstate actors on the geographic periphery of states and empires plan, execute, and, in most cases, fully carry out instances of territorial expansion without the aid, authorization, or foreknowledge of leaders at home in the capital. This might consist of the military or colonial army engaging in armed conquest, diplomats or colonial officials annexing territory, or merchants and other private actors seizing territory. Whatever the case may be, the crucial point at this stage is that the leaders in the capital with responsibility for national or imperial security policy are not involved in the planning, authorization, or execution of the expansion.

I argue that this first step is largely the result of inadequate central control over the periphery. It is a manifestation of what is known as a “principal-agent problem”—a situation in which one actor (the principal) delegates decision-making authority to another actor (the agent), yet the agent makes decisions that differ from those the principal would make if it were on the ground making decisions itself. In this first stage of unauthorized peripheral expansion, the principal is the central leadership of the state or empire, and the agent is a state or nonstate actor on the periphery, and the problem is that the agent has just acquired foreign territory without the necessary permission or authority to do so.

Principal-agent problems are exacerbated by a lack of central control over the periphery, typically in the form of the ability to monitor the behavior of peripheral agents. When leaders in the capital have difficulty monitoring, and thereby controlling, their peripheral agents, unauthorized peripheral expansion is more likely to occur. In contrast, when leaders in the capital are better able to monitor and control their peripheral agents, unauthorized peripheral expansion is less likely to occur. In the history of great power territorial expansion, the ability to monitor and control the periphery is crucially determined by the state of transportation and communications technology, with rudimentary technology hindering central control and advanced technology enabling it. However, this is not the only determinant. In a number of important cases, weak civilian control over the military can hamper civilian or central control to the point that unauthorized peripheral expansion becomes more likely. In short, we should expect the incidence of unauthorized peripheral expansion to vary inversely with the amount of central control over the periphery: when central control is weaker, we should see more, and when it is stronger, we should see less.

In the second step of the process of inadvertent expansion, which I refer to as subsequent central authorization, the peripheral agents present to their principals in the capital the partly or wholly acquired territory as a fait accompli. This initiates a deliberative process in the capital that results in a decision among central leaders to either reject the fait accompli, leaving their peripheral agents to fend for themselves, or accept the fait accompli, completing the process of inadvertent expansion.

It is important to recognize that the very act of unauthorized peripheral expansion changes “the facts on the ground” and thereby alters the strategic calculus of the leaders in the capital. It places constraints on the leaders’ ability to promptly reject the territorial claim for three basic reasons. First, unauthorized peripheral expansion has the effect of sinking the costs of territorial acquisition, since these costs cannot be recovered once incurred. Second, unauthorized peripheral expansion tends to generate domestic political pressure on the leaders in the capital to support their own agents and nationals. And third, unauthorized peripheral expansion tends to engage the national honor and prestige of leaders in the capital in ways they simply were not engaged before, making withdrawal significantly more difficult. Thus, for reasons of sunk costs, domestic political pressure, and national honor, leaders are often constrained in their ability to reject the territorial claims of their wayward agents.

However, despite these constraints, leaders in the capital still have one other crucial consideration: the geopolitical risk associated with acquiring the territory in question. When leaders expect few significant geopolitical risks associated with acceptance of the fait accompli, they are significantly more likely to subsequently authorize the acquisition. In contrast, when leaders expect significant geopolitical risk associated with acceptance of the fait accompli—such as crippling economic isolation, a severe interstate crisis, or the possibility of a major war with a regional power or rival great power—they will be far less likely to authorize the acquisition.

In sum, inadvertent expansion is most likely to occur when leaders in the capital lack adequate control over their peripheral agents and when there are few geopolitical risks associated with acceptance. To put it simply, inadvertent expansion is most likely in low-control, low-stakes contexts. Even in cases where the leaders do not positively “want” the territory in question, the constraints imposed by unauthorized peripheral expansion are often enough to force their hands and encourage subsequent central authorization, leading to inadvertent expansion.

To be absolutely clear, the fact that any individual case of territorial expansion is inadvertent in no way absolves the governments in question of moral responsibility for the associated horrors of conquest and empire. First, as the case studies in this book demonstrate, inadvertent expansion is no more humane than its intentional counterpart. Second, to have unconstrained actors on the periphery basically presupposes the existence of an empire, and the construction of such empires typically involves significant amounts of intentional territorial expansion by the capital. In other words, the path to instances of inadvertent expansion is usually forged by many past intentional expansion decisions. And third, state and imperial leaders do have agency in these cases, since they are the ones who make the ultimate determination as to whether to reject or retain the territories in question. Thus, describing territorial expansion as inadvertent does not make it any more justifiable. The aim of this book is not to excuse territorial expansion or empire by uncovering its inadvertence but instead to understand and explain this important and underappreciated process in the history of great power politics.

Importance and Contributions

Inadvertent expansion is a surprisingly common phenomenon. Far from being an unusual and highly contingent outcome—a curiosity to be pondered by historians of particular empires in particular time periods—it was, in fact, a regular feature of great power politics right up to the 1930s. As the findings of chapter 2 show, nearly one-in-four instances of territorial expansion among great powers between 1816 and 2014 are inadvertent in nature. It is experienced by all but two (Austria-Hungary, China) of the nine great powers during that period. It occurs regularly over the course of more than a century, from as early as 1818 to as late as 1932 and in all regions of the world. Indeed, a wide variety of territories were acquired in this manner, from remote islands in the South Pacific, to topographically forbidding central African kingdoms, to densely populated regions of East and Southeast Asia (see figure 0.1). In short, inadvertent expansion is a regular feature in the modern history of great power politics.

This book makes three central contributions to the literature on territorial expansion and to international relations theory more broadly. First, it articulates the concept of inadvertent expansion, a phenomenon that has been largely ignored in the international relations literature. While the idea of periphery-driven territorial expansion is far from entirely new—particularly in the history of empire and some theoretical work on imperialism—it has yet to insert itself into the core debates over the causes and processes of territorial expansion in international relations scholarship. While a few scholars have recognized that territorial expansion can vary in terms of its process or the form it takes, very few have discussed the radically decentralized nature of inadvertent expansion. By recognizing the phenomenon of inadvertent expansion, clearly conceptualizing it in terms of its basic steps and attributes, and observing it across dozens of cases, this book thus furthers our understanding of varieties of territorial expansion and how states and empires come to be.

Second, I present a new theory of inadvertent expansion. Although the phenomenon of inadvertent expansion has gotten considerable attention in imperial history, with many articles and books devoted to instances or campaigns of inadvertent expansion, few scholars, whether in history or international relations, have tried to explain it comprehensively across space and time. Drawing on diverse bodies of literature—including imperial history, the principal-agent theory, behavioral economics, and international relations—I construct a theory that applies to a broader set of cases and a longer swath of time than existing explanations for periphery-driven territorial expansion.

Third, I conduct the first-ever comprehensive accounting of inadvertent expansion in the modern history of great power politics. I present data comprising 258 observations of territorial expansion by the great powers since 1816, each of which is coded with respect to whether its expansion was inadvertent or intentional in nature. This allows me to show broad patterns of inadvertent expansion across great powers, regions, and historical eras, and it provides a wide variety of historically rich cases with which to illustrate how inadvertent expansion works in practice.

Understanding inadvertent expansion may seem like merely a matter of historical interest. After all, if rudimentary technology stands as one of the reasons why inadvertent expansion occurred, then advances in technology would appear to make this form of expansion obsolete. Yet, as I discuss further in the book’s conclusion, inadvertent expansion has contemporary relevance in a number of important ways. First, the disappearance of great power inadvertent expansion likely played some role in contributing to the broader decline of territorial expansion we have observed since 1945, helping shape the world we inhabit today. Second, inadvertent expansion has not completely gone away. There are a number of contemporary cases of the militaries of smaller states in developing world contexts claiming territory, seemingly without government authorization. And third, while no great power has experienced inadvertent expansion for many years, the mechanisms that drove it forward—sunk costs, domestic politics, and honor concerns—may still motivate other inadvertent foreign policies, such as conflicts, crises, even wars.

Road Map

The pages that follow present a theory of inadvertent expansion then test and illustrate it in the modern history of great power politics. I begin, in chapter 1, by laying out my theory of inadvertent expansion in two parts. The first part covers the unauthorized peripheral expansion stage of inadvertent expansion, drawing on principal-agent theory to explain when we should expect this phenomenon to be more or less common. The second part covers the subsequent central authorization stage of inadvertent expansion, showing how forces such as sunk costs, domestic politics, international honor, and geopolitical risk can encourage or discourage acceptance of the fait accompli. I close this chapter with a detailed discussion of the research design, the methods employed, and the case selection criteria that guide the empirical chapters that follow.

In chapter 2, I present the broad patterns of inadvertent expansion among great powers. I introduce new data on great power expansion between 1816 and 2014, showing how inadvertent expansion varies (or does not) across a wide variety of important factors. I also support the two central claims of my theory: that a lack of central control over the periphery and conditions of low geopolitical risk are associated with more inadvertent expansions. Using a linear probability model and the great power expansion data, I show that territorial expansion is significantly more likely to be inadvertent than intentional when the territory in question lacks a connection to the global telegraph network as well as under conditions of relatively low geopolitical risk.

Chapters 3–7 present a series of paired comparative case studies of successful and failed inadvertent expansion in the modern history of great power politics. These cases show how the explanatory variables and outcomes vary in ways expected by the theory. They cover a variety of great power actors, regional contexts, and historical time periods, and, as I detail further in chapter 1, they were selected to conduct controlled comparisons, illustrate the mechanisms of the theory, and demonstrate its generalizability.

In brief, chapter 3 presents two US cases, the acquisition of Florida and the nonacquisition of the Republic of Texas. Chapters 4 and 5 each examine two cases involving the Russian Empire and the French Empire. Whereas the former looks at Russia’s acquisition of parts of the Khanate of Kokand and its nonacquisition of the Ili region, the latter looks at France’s initial nonacquisition of the kingdom of Tonkin, and its ultimate acquisition of Tonkin. Chapter 6 presents the only cross–great power comparison in the book, examining Japan’s acquisition of Manchuria and Italy’s nonacquisition of the port city of Fiume. Chapter 7 looks at Germany’s acquisition of what is now Tanzania and its nonacquisition of what is now Kenya and Uganda. The book’s conclusion then reviews the arguments and central findings, discusses the contemporary relevance of the theory, and presents its most important theoretical and policy implications.