International law is not a topic one usually associates with the rise of America's global power. But in Legalist Empire: International Law and American Foreign Relations in the Early Twentieth Century, Benjamin Coates makes a convincing case that international lawyers were central to American expansionism as well as to its entry into World War I. Legalists helped to provide the rationale to justify the colonization of the Philippines and other territories, developed legal codes that protected corporate interests overseas, and created an organizational infrastructure promoting a vision of world order compatible with American interests. International law “cast an imperial shadow,” Coates declares, and his book explains how, thus providing a new interpretation of a crucial era in American diplomatic history.

The heart of Coates's analysis lay in his careful description of the ideology of “legalism” that animated international lawyers such as Elihu Root, John Bassett Moore, and James Brown Scott. These “lawyer-officials” viewed law as “an apolitical expression of reason” and the development of international law as the expression of “advancing civilization” (2, 71). Sovereign states, they believed, were increasingly interdependent and should therefore see international cooperation under formal rules as both practical and an “ethical duty” (71). Legalists did not call for world government to implement a regime of international law. Instead, they “reconciled sovereignty and internationalism by assuming that nation-states would learn to act in a more ‘civilized’ manner” (71). This process would be spurred by nation-states holding conferences to codify international law and by the creation of an international court run by legal professionals. As the court clarified the law and established precedents, it would become a “trusted source of neutral authority to settle disputes” without violence (3). Sanctions would not be necessary to enforce the law as an enlightened, educated public opinion developed that understood that states had not only rights under the law, but also a duty to obey its dictates.

The legalist project was compatible with American imperialism for several reasons. Most basically, legalists understood the rule of law “as the application of civilization to restrain irrational behavior” (10). In relations between the Great Powers, this meant substituting legal procedures for war. When applied to “backward areas,” however, “it meant the extension of ‘civilized’ control through empire” (10). Legalists also perceived that the existing body of international law gave sovereign states “the right to acquire territory and to rule it as they saw fit” (47). If the United States was a member of the community of civilized nations, it had this right too, regardless of Constitutional objections to colonialism raised by anti-imperialists. Exercising this legal right did not make the United States “European” in the eyes of the legalists. Instead, it was consistent with the progressive development of civilization and with a system of international law modeled on American institutions like the Supreme Court. In addition, legalists promoted an interpretation of international law emphasizing that states could intervene in other nations “to protect the property rights of their citizens abroad,” a claim that underlay the Roosevelt Corollary and William Howard Taft's Dollar Diplomacy (120). To be sure, Latin American legal theorists and officials contested this view. But American and European lawyers, supported by a growing network of professional associations funded in part by the Carnegie Endowment for International Peace, successfully asserted it at The Hague Peace Conference in 1907. As Elihu Root argued, under the international law of civilization, states had duties as well as rights – and one such duty was the payment of debts to foreign capital.

The legalist outlook on international law also had an impact on U.S. foreign policy during World War I. During the neutrality period, legalists in the State Department, led by James Brown Scott and Robert Lansing, reinforced and justified Woodrow Wilson's bias toward the Allies. According to Coates, they recognized that Britain's blockade against Germany “stretched accepted rules of international law beyond their breaking points” (144). But they did not want to back up American protests over this issue with threats of reprisal or war. Coates attributes this posture to their belief that British leaders shared their legalist ideology and would arbitrate U.S. claims connected with the blockade after the war. Germany, in contrast, appeared to American legalists to have contempt for international law and hostility toward democratic institutions, as shown in the Reich's invasion of neutral Belgium and its “inhuman” submarine warfare (145). Viewing a German victory in the war as a dire threat to their entire legalist project, they supported President Wilson's threatening protests concerning Germany's submarine campaign and his insistence, rejected by other neutrals, that citizens from neutral states had a right to travel on armed belligerent ships. Indeed, Coates argues, administration legal experts, led by Scott, provided detailed opinions supporting Wilson's extreme stance on the armed ship issue, which he suggests ultimately became a key factor leading to war between Germany and the United States.

The last major substantive chapter of Coates's book examines the legalist perspective on collective security during and after the war. Here too his analysis is impressive. Wilson's outlook on international reform had little in common with that of the legalists, Coates argues, as it focused on a league of nations guaranteeing the political and territorial integrity of its members rather than on the codification of international law and the creation of an international court. This view reflected Wilson's moralistic political philosophy, his suspicion that lawyers were tools of corporations, and his conviction that the war showed the need for sanctions to enforce civilized behavior among states. Some legalists, such as Taft, agreed with the latter point. They formed the League to Enforce Peace (LEP), which essentially asserted the pre-war legalist program but added a provision requiring league members to use force against any state going to war without first following a conflict resolution procedure. Many leading legalists did not join the LEP, however, because they thought its program, like Wilson's, infringed upon national sovereignty too much and would never be followed by nation-states in practice. The war, then, shattered the unity of the legalist movement, diminishing its influence over American foreign policy.

Deeply researched and well-written, Legalist Empire is an important work. It should be on the reading list of anyone interested in American foreign relations, international law, or imperialism.