Jennifer Pitts's brilliant Boundaries of the International: Law and Empire is a history of the imperial origins of international law. Arguing against what she calls the “conventional narrative” of the emergence of international law, Pitts makes clear that international law did not arise primarily from the efforts of free and equal European states to organize intra-European relationships. Instead, Pitts demonstrates that it emerged from European imperial encounters with the non-European world, encounters to which she argues European legal authorities consistently responded by marking the “boundaries of the international.” Throughout the history of international law, that is, attempts to define an international law binding on all were repeatedly linked with efforts to exclude non-European nations from the international order. From this common feature of European legal thinking others flowed. The first was a tendency to justify imperial conquest and unequal terms of engagement with reference to values which, although portrayed as universal, were the result of rather narrow thinking, not to mention narrow interests. The second was a tendency to occlude the fact of empire with assertions that the state was the fundamental component of international order.

At the core of much of Pitts's inquiry is the question of how discourses as lyrically universalizing as those on which the law of nations, and later international law, were founded could be sources of the abiding parochialism, localism, and chauvinism that Pitts demonstrates thoroughly structured much late seventeenth-, eighteenth-, and nineteenth-century European legal theory. It is in both emphasizing and answering this question that Pitts makes some of her most trenchant contributions to what Lauren Benton has called “the imperial turn in the history of international law.”

The reasons that international legal thinking could often be so universal in pretension, but so parochial in its concerns, varied over time. For example, Pitts demonstrates that the exclusionary gesture characteristic of European international legal thinking went largely unexamined by most seventeenth- and eighteenth-century Europeans because it was often unreflectively submerged within visions of international order––such as those of Grotius and Vattel––that went to great efforts to deny that international law applied to and emanated from a subset of humanity. International law, in this work, was not primarily grounded in the beliefs and practices of Christendom, but instead in natural law itself. However, despite the universalistic claims in which these arguments were couched, Pitts demonstrates that they were often grounded in a parochial and uninterrogated belief that, at that historical moment, the only practices consistent with natural law were those of European nations. Thus standards of international conduct that seventeenth and eighteenth century figures claimed reflected universal judgment were in fact often reflections of the beliefs of a small subset of thinkers from a small subset of the world's nations—beliefs that were in turn justified with reference to a small subset of international practices that in no way included all those in which European empires were engaged during the period.

Although the tenor of this particularism changed as the eighteenth century gave way to the nineteenth, its profound effect on conceptions of international law continued unabated. Thus, Pitts teaches us that, even as international lawyers of the nineteenth century began to explicitly argue that international law emanated from the practice of Europeans, not some hypostasized universal natural law, they continued to hold fast to the belief that their particular practices should be binding on all because they represented the highest rung on a ladder of a civilizational progression to which all should aspire. Therefore, even though figures such as Henry Maine and William Edward Hall argued that international law represented values that not all people were yet able to understand or conform their behavior to, they believed that these values were standards against which all peoples could be judged. As a result, in the minds of many of the men who led the effort to codify international law in the nineteenth century, those who resisted hostile actions that Europeans claimed were justified by international law were not only “enemies,” they were also “outlaws” against whom inequitable terms of agreement could be imposed, and against whom violence could be used justifiably.

Through careful reference to a wide variety of case studies, of which those referenced here are just a sample, Pitts makes clear to both contemporary historians and international lawyers that the history of international law is in large measure the history of the means by which “substantive inequalities” have become “inscribed in formally legal principles” (191). In doing so, Pitts not only makes a vital contribution to political theory, international law, and intellectual history. She also offers critical tools that those working to oppose inequality in the contemporary international order can use in their efforts to make certain that the future of international law is not, like its past, a story of “universalism and hierarchy intertwined” (191).