Between 1939-1941, from the time that Germany invaded Poland until Japan attacked Pearl Harbor, Americans engaged in a debate as intense as any in U.S. history. In Storm on the Horizon, prominent historian Justus D. Doenecke analyzes the personalities, leading action groups, and major congressional debates surrounding the decision to participate in World War II. Doenecke is the first scholar to place the anti-interventionist movement in a wider framework, by focusing on its underlying military, economic, and geopolitical assumptions. Doenecke addresses key questions such as: how did the anti-interventionists perceive the ideology, armed potential, and territorial aspirations of Germany, the British Empire, Japan, and the Soviet Union? To what degree did they envision Nazi Germany as a bulwark against the Soviet Union? What role would the U.S. play in a world increasingly composed of competing economic blocs and military alliances? Storm on the Horizon is certain to become the standard study of this tumultuous time and will require readers to reevaluate their understanding of the United States entry into World War II.