The most powerful country in the contemporary world was once a loose confederation of states. And today various scholars and political leaders foresee the European Union's gradual transformation into a strong, unitary state. Given that the prevailing realist wisdom in international relations suggests that states should jealously guard their sovereignty and buck attempts to subordinate them or otherwise proscribe their autonomy, Joseph Parent endeavors to understand how and why states sometimes voluntarily enter into enduring unions with one another.
As I am a student of secession—focused on precisely the opposite of union—my immediate reaction is that while the United States is an important country, states almost never voluntarily unite with other states. Disintegration, separatism, and societal fractures are far more numerous than voluntary unions. But for Parent, union's relative scarcity is part of its allure; he wants to disabuse overly optimistic constructivist and liberal notions that unification can occur under more routine, and perhaps increasingly common, circumstances (p. 24). Uniting States argues that fairly extraordinary conditions undergird the opportunity for union and that many factors can derail the process along the way. Yet the strength of the United States and the potential ascendence of a united Europe make an examination of these unions worthwhile. Surveying the entire modern historical universe of symmetrical, voluntary unions in world politics, Parent finds only four cases fitting his definition. Two of the unions were successful and enduring and two of them ultimately failed. The United States and Switzerland comprise the former category while the union of Sweden and Norway and Simon Bolivar's Gran Colombia project populate the latter. All of the unification efforts occurred between 1785 and 1845 (p. 27).
Parent argues that voluntary union is an extreme form of balancing alliance for states facing a powerful external threat. Before the prospect of union is even contemplated, three background conditions must obtain. First, states must face an “optimally intense” security threat. It must be too large to be confronted by normal alliance alone, but not so big as to be futile. It must also be “indefinite,” or anticipated to last between 25 and 50 years. Finally, it must be “symmetrically affecting.” None of the allies should expect to gain or sacrifice disproportionately from cooperation (p. 8). But there are also two important, more proximate, domestic causes. First, elites in each state must use the threat to evoke a security crisis undermining the existing international order. Next, these elites must use the media, military, and political process to persuade their domestic audiences that union is necessary and ultimately use them to realize the union (ibid.). Moreover, the author contends that the process also works in reverse; a significant diminution of the threat that provoked unification, its asymmetric affect, or its growth beyond what the alliance-cum-state can balance will strain the domestic partnership, despite the lag of institutional momentum, and cause it to unravel (pp. 15–16). Thus, a modest theory explaining extraordinary unions also provides potential leverage on the far more common phenomenon of state dissolution and failure.
Uniting States begins with a theoretical chapter laying out the preferred realist argument and three alternative takes on union provided by constructivism, liberalism, and a hybrid approach termed “binding” that is embodied in Daniel Deudney's republican security theory. Four case studies follow over the next five chapters (the American case receives two) that explore the competing hypotheses. Chapter 8 extrapolates from the cases to the future of Europe, where Parent finds little hope for unification so long as the American security guarantee persists. The book formally closes with a brief discussion of its implications for international relations theory and policy. An appendix that follows also contains an interesting discussion of Machiavelli's (perhaps proto-realist) depiction of violent union in The Prince.
Although historians will certainly contest the details of Parent's case studies—and the American case in particular, due to deeply held beliefs regarding its origins and the vast literature on the topic—the book offers a genuinely novel take on the uncommon confluence of factors that drive independent states to surrender their freedom and voluntarily subordinate themselves permanently to a new governmental authority. The author offers a reasonable theory that identifies the common factors and similar processes behind four cases that would typically be considered idiosyncratic and unique unto themselves. Further, the theory is well grounded in the scholarly literatures on cooperation, institutions, and alliance. Last, this is a genuinely good read. Parent writes in an accessible, lucid, and conversational manner even though the formal structure of the book has the conscientious and deliberate patterning of good comparative case research; this is no mean feat.
With that said, no wall is impregnable, and so I hope to offer some constructive criticisms in order to provoke a continued conversation on the dynamics of state birth and death. Parent and I share a common cause, as I agree that they are an important yet undertheorized aspect of world politics.
One concern lies with construct validity and the logic of case selection. The nature of the phenomenon being explained (voluntary symmetrical union) at times feels too narrowly constrained. Most postcolonial unions are excluded because they were supported or encouraged by the imperial power or another stronger state. Also excluded are any instances of union where an imbalance of capabilities among the uniting parties existed. The two types of cases were disqualified on the presumption that coercion was at play; union could not be considered voluntary (p. 5). But whether coercion was, in fact, at play is an empirical question that can be answered through examination. Britain preferred a united independent Federation of the West Indies, but Jamaica had other plans. Perhaps the United Arab Emirates unified voluntarily despite Abu Dhabi's disproportionate size. I have only a cursory knowledge of the politics of union in these two examples, and I have not endeavored to survey historical unions myself, but I suspect that a slight relaxation of the strict standards for inclusion would have yielded a number of additional, more contemporary, cases worthy of examination.
Relatedly, while Parent anticipates potential criticisms that he has selected on the dependent variable, because he has identified the universe of cases and is interested in identifying the necessary conditions for union, he jettisons those concerns. Unfortunately, not all of the methodological concerns regarding case selection can or should be dismissed so easily. If the author is right that the four unions comprise the entire universe, then the case studies might be more appropriately labeled descriptive statistics than tests of the theory (presuming that the theory is not purely deductive, but also derives at least in part from the cases). Theory testing might have been better served by additionally searching for cases of nonunion in the face of an “optimally intense, indefinite, symmetrical security threat”; Parent suggests that this as an outcome that would potentially falsify his theory, but does not endeavor to explore its existence within the text (p. 26). Nor were historical instances identified in support of the argument, that is, where the background conditions were present but elites did not pursue union or successfully achieve it and suffered the adverse consequences of “underbalancing” (to borrow a term from Randall Schweller) as a result. There is a rich and immanently testable theory of voluntary union here, but the too narrow dependent variable and case selection unduly limit its leverage.
Next, the cases are old. The most recent instance of voluntary, symmetrical union was Switzerland's in 1848. This is not a problem in and of itself, but does create potential difficulties in Chapter 8 when the book endeavors to project the future of the European Union—whether it will gradually coalesce into a single state, stagnate at or near the current status quo, or reverse its course and dissolve. Parent acknowledges that much has changed since the historical unions examined in the bulk of the manuscript formed, and he rightly tempers confidence in his predictions regarding the EU. Still, more work could be done to identify the theory's scope conditions and more precisely outline how the world has changed and how those changes might affect the veracity of his predictions. The author does not do enough to convince the reader that the historical cases and the EU are meaningfully comparable and not mere pseudoequivalencies. All of the cases occur within a 60-year period. Moreover, those who foresee a gradual union for Europe are likely to describe it as a novel project without historical precedent. If Parent wants to speak to this audience or embolden Euro-skeptics, then the onus is on him to demonstrate that the fundamental workings of the system have not changed so much that these historical precedents hold no meaning.
Finally, the book claims too much. Parent is on much firmer footing regarding his theory's ability to explain the formation of voluntary union than when he attempts to explain their dissolution via the same mechanism. As the book closes, the author even suggests that his theory can help to explain the Soviet Union's demise, neither a voluntary nor a symmetric union (pp. 155–56). Aside from a love of symmetry, there is no good reason to believe that the causes of union are the inverse of those that cause dissolution. If the fundamental difference between anarchy and hierarchy—between a loose confederations of states and unitary states—is enforceable unity, then it is unclear to this reader how the threat mechanism works in reverse. Parent argues that asymmetric threat perceptions within a union tear at its seams, but it is unclear how or why varied perceptions of threat would emerge within a unitary state. In a state whose leaders have entered into such a strong federation that they have surrendered their sovereignty to a unitary and inviolable whole, and where local leaders have been replaced with common ones, why would a threat to some not be perceived as a threat to all? Put differently, in order to make the theory work in reverse, one has to violate the essential realist tenet that states are unitary rational actors—or at least that federal states are.
I believe that the source of this overreach lies in the cases of failed union examined within the book. Rather than completed projects that failed, it seems more accurate to portray the union of Sweden and Finland and Gran Colombia as incomplete unions at best. The Sweden and Finland case is more alliance than union (pp. 100–101), and Gran Colombia was only unified for six years before it began to disintegrate (p. 126). Therefore, while we may indentify the diminution of threat as causally important to each of these two states' demise, they offer fewer clues as to how or why the United States or Switzerland might one day disband than Parent claims. Then again, he may recognize the theory's limitations. The United States case suggests as much because he does not use the diminution of external threat or asymmetric threat perceptions to explain the sources of the American Civil War, which, despite claims to the contrary, had a very real prospect of transforming hierarchy into anarchy in that union (p. 58).
Furthermore, although not much international relations theory is dedicated to the topic of voluntary union, there is no shortage of work on state dissolution, partition, or separatism and civil war. Almost none of it is referenced within the text, even though it provides at least as compelling an explanation for disunion as the one on offer. As someone who has dedicated a significant amount of thought to state dissolution and secessionism, perhaps I have judged Uniting States too harshly on this account. After all, it is not the book's central claim. But it does detract from the work's genuinely novel and insightful contribution to the field.
