The causes and consequences of World War I preoccupied diplomatic historians for decades following the war's end. In 1926, Harry Elmer Barnes argued[1] that there had been no compelling reason for the United States' entry into the conflict, other than President Woodrow Wilson's idealist ambitions. At the height of the Great Depression, Charles Beard suggested[2] that American foreign adventures created more problems than solutions and advised the Franklin D. Roosevelt administration to pursue an Open Door policy at home and provide economic opportunities for American workers. Early in the Cold War, George Kennan, architect of America's Containment Policy, criticized the tendency of US officials to view foreign policy through a moral lens.[3] His contention that realism, not idealism, should guide diplomatic decisions influenced a generation of foreign-policy makers, notably Henry Kissinger. New Left historians partly agreed with Kennan's assessment of American diplomacy, but emphasized that, since the 1880s, economic interests had driven US international policy.[4] This thesis catalyzed a critical reconsideration of the relations between the United States and the rest of the world, especially Central and South America. And, in the view of New Left scholars, it also helped explain the war in Vietnam.

The centenary of the Great War has prompted reassessments of earlier scholars' interpretations of its effects on the later course of events in the twentieth century. Among the best of these is the work here under review, in which prolific historian Peter Clarke (Cambridge Univ.) challenges those who dismiss the role of morality and idealism in explaining the origins and the legacy of World War I: "A neglected factor, I suggest, is the influence of Anglo-American liberalism and its moral perspective" (17). That is, an agreed upon common moralist agenda induced the United States to enter the conflict and constituted a blueprint for avoiding future military catastrophes.

Clarke concentrates on four key figures: Prime Minister David Lloyd George, economist John Maynard Keynes, and President Wilson are familiar to readers of popular as well as scholarly histories of the Great War. The inclusion of the fourth figure—William Ewart Gladstone—comes as a surprise, since the four-term prime minister of England died in 1898. The author clarifies his rationale for inclusion: "this book is not about Gladstone, but it is inescapably concerned with the pervasive influence of the Gladstonian legacy" (22). He believes the motives and methods of British and American diplomats reflected the influence of Gladstone's political and philosophical ideals. Specifically, the prime minister maintained that diplomatic actions must be based on a moral agenda and that immoral actions must be punished in order to maintain an international order that secures political and economic stability for all persons, not just the upper classes.

The author uses Gladstone's speeches and writings[5] to argue that, by ca. 1910, Anglo-American diplomats had adopted a common vocabulary, whereby Gladstone's concepts of guilt, morality, and political and economic equality instilled leaders of the Allied powers with "an ethically strenuous version of liberalism" (14) by the outbreak of war in 1914. This "moral populism" (18) later influenced the goals of Prime Minister Winston Churchill and President Franklin Roosevelt throughout World War II. The author defends this thesis by discussing the major figures and events of the Great War in fourteen chapters (a nod to Wilson's Fourteen Points).

Clarke acknowledges the benefits of colonial empires to Great Britain and the United States, but maintains that moral idealism, rather than aggression by the Central Powers, better accounts for their entrance into the war. The invasion of Belgium and German U-boat attacks on civilian ships led to a public outcry, but Wilson claimed that a diplomacy of principle—not of pragmatism—must take precedence over brute force and form the basis of shaping the peace. He promised "to bring updated liberal principles to the rescue and redemption of the whole world" (212). Many historians see Wilson as either a romantic ignorant of the realities of foreign policy or a stubborn religious moralist who refused to see that compromise offered the best path to achieving his goals. Clarke differs in his assessment of the Fourteen Points and concludes that the legacy of Wilson's rhetoric was the best hope for furthering a liberal agenda and avoiding a future world war.

The author concludes that two narrative threads shed the most light on the war and its legacy:

In his well-written, entertaining, and discerning new book, Peter Clarke offers an alternative interpretation that identifies a liberal moralism shared by Anglo-American diplomats rather than a selfish pragmatism among the causes of World War I. He also refutes Leon Trotsky's claim that the war was the locomotive for a revolution entailing a worker's rebellion and the destruction of capitalism. Instead, he counters that workers' patriotism and the flexibility of western liberalism and capitalism were keys to avoiding revolution.