In this excellent study of United States international lawyers in the early twentieth century, Japanese scholar Hatsue Shinohara focuses on their major contributions to United States foreign policy at this important time of transition in international history. Through their writings and personal participation, they helped articulate America's official vision of a new world order, defined by international law, and America's place in it after World War I. Building on the legal-historical scholarship of Jonathan Zasloff, she notes the central role of lawyers Elihu Root, Robert Lansing, Charles Evans Hughes, Frank Kellogg, Henry Stimson, and Cordell Hull, who served as United States secretaries of state. Root, Hughes, and Hull also held the presidency of the American Society of International Law from its founding in 1906 until 1942, except during James Brown Scott's tenure as president during the decade 1929–39.

Shinohara examines particularly the new international law that emerged from World War I, and the structured international relations during the interwar years. She notes the division between traditionalists, including Root and Lansing, and reformers, including Stimson and Hull, and to some extent Hughes and Kellogg. Whereas traditionalists emphasized the state's sovereignty, reformers envisaged a new international society, which would transcend an individual state's national interest and instead promote universal rights and obligations. Typically, reformers were inspired by President Woodrow Wilson's vision of the League of Nations. Although Wilson's own role is peripheral in this book, the Covenant of the new League, which he pursued as his top priority at the 1919 Paris Peace Conference, became one of the founding legal documents that defined the new international order. The 1921–22 treaties of the Washington Conference, the 1928 Kellogg–Briand Pact, and the 1932 Stimson Doctrine also expressed the new international law that shaped interwar international relations. Debates in the United States over the Neutrality Acts of the 1930s also pitted reformers against traditionalists. Reformers such as Quincy Wright, who advocated collective security, denounced traditionalists such as Edwin M. Borchard, who espoused United States neutrality.

The eventual entry of the United States into World War II discredited traditionalists, who were identified with isolationism, and enabled reformers to grasp their second chance to create a new international society, such as Wilson's vision of the League of Nations. President Franklin D. Roosevelt and his secretary of state Cordell Hull sought to implement this Wilsonian postwar order with the new United Nations Organization. The affirmation of universal rights and obligations also justified the Nuremburg and Tokyo war crime trials. Reformers thus laid the legal foundation for what Elizabeth Borgwardt called A New Deal for the World (Harvard University Press, 2007).

As Shinohara observes, the vision of a new international society that triumphed by the end of World War II emerged primarily from the scholarship and statecraft of United States international lawyers. The British also contributed and embraced the concept of a new liberal world order. She notes, however, that Japanese scholars and statesmen during the 1920s only partly accepted this vision and those of the 1930s rejected it. Outside of the Anglo-American world, the ideas that reformers among United States international lawyers promulgated as universal were actually not. Therefore ironically, as she recognizes, profound differences in world views between traditionalists and reformers were central to the international conflict between the United States and Japan during the interwar years, culminating in Pearl Harbor. The reformers' pursuit of a new international society thus contributed to war. Shinohara's comparisons of United States and Japanese—and to a lesser extent other national—ideas about international law during the interwar years enable her to place the role of United States lawyers in a broader comparative framework. She reveals that what many United States international lawyers regarded as universal principles, and touted as the legal foundation for a new international society, were not necessarily accepted as such in other nations.

This insight led Shinohara to a realistic and cautious conclusion. “To this day,” she writes, “sovereign states remain the basic unit of international relations. And in spite of the trend toward regional and global integration, the number of sovereign states has continued to increase. The new international law did not take the place of the old. Instead, international law was transformed and its scope expanded, in large part by the concept of the ‘family of nations’ and by the abolishment of the legality of war” (208). In other words, reformers among the United States international lawyers, both in scholarship and statecraft, had failed to transform international relations as much as they had hoped. Traditionalists, who had warned about the limits of United States power to reform the world, had wisely contributed a realistic note of caution to the ongoing debate.