After World War I, U.S. President Woodrow Wilson embarked on a major campaign, inspired by the ideals of the Progressive era, to bring national self-determination to eastern Europe. Wolff’s enthralling account traces the way the president’s principles clashed with the messy reality of historical frontiers and political rivalries in the region. Wilson’s belief in the right of all peoples to decide their own futures collided with his involvement in what he described as “carving a piece of Poland out of Germany’s side” and “rearranging the territorial divisions of the Balkan states.” He belatedly grew aware of the problem of “national minorities,” seeing that their aspirations were impossible to reconcile with those of majority communities. The system of nation-states in eastern Europe, which emerged thanks in large part to Wilson’s efforts, persisted through most of the twentieth century. But in the process, as Wolff describes, Wilson discovered that his dream of justice and self-determination was a barely sustainable fantasy.