All militaries conduct war games as a means of preparedness, readiness, strategic deterrence, intergovernmental planning, and to provide concrete options to civilian leaders in support of their policy and national security objective. Peacetime planning allows the military to anticipate potential threats and develop responses, systems, and forces before a crisis emerges. 

War Plan Orange was one of several plans outlining the United States military’s detailed strategy for a future war. The plans were developed as early as 1919. War Plan Orange was the plan for a potential war in the Pacific. Some have argued that War Plan Orange is evidence that the United States always intended to begin a war with Japan; the logic being why else would you plan a war? The United States had found itself completely unprepared for the First World War and so even as it stood down its wartime military, planning for future wars began. Japan was the natural candidate given its evolving militarism and colonial expansion undertaken by Japan that began in the late 1860s with the Meiji Restoration. This evolution inexorably continued up to and into the start of World War II.

The Plan was part of the Navy War College curriculum. Virtually every senior naval leader in the Pacific had studied Plan Orange and contributed to it as new circumstances, technology, and situations arose. As one historian noted: “it was part of their DNA.”