This chapter examines the War Department’s role in the formation of US policy toward the European war and the growing crisis in the Pacific between the Fall of France in June 1940 and the Pearl Harbor attacks in December 1941. This chapter argues that the War Department played a pivotal role in shaping American policy and actions in both the Atlantic and the Pacific, but in different ways. In the Atlantic, the War Department was a primary impetus within the Roosevelt administration for increasingly interventionist policies. It consistently pushed President Roosevelt to act and influenced the politics of his decision-making at several crucial junctures. The War Department provided the crucial nexus between the executive branch, Congress, and outside pressure groups as the US moved toward war. In the Pacific, the War Department pressed for a firm stand against Japan but helped muddle Far Eastern policy by working to undermine the State Department’s more cautious stance. This bureaucratic warfare made it difficult to foster consensus around US deterrence actions and contributed to worsening relations between Washington and Tokyo, setting the stage for the Pacific War.