The Joint Chiefs’ greatest accomplishment in World War II was planning and executing a two-front war, one in the European-Atlantic theater and the other in the Asia-Pacific region. Even though the agreed Anglo-American strategy gave primary importance to defeating Germany, the attack on Pearl Harbor and Japan’s rapid advances during the early stages of the war created a political and military environment that focused heavy attention on the Pacific and Far East. For the first year or so of the war, bolstering the American posture there consumed as much, if not more, of the Joint Chiefs’ energy as Europe. At the same time, the absence of an agreed long-range wartime strategy made it practically impossible for JCS planners to draw a clear distinction between primary and secondary theaters. As a result, by the end of 1943, deployments of personnel were practically the same (1.8 million) against Japan as against Germany. Thereafter, as the United States stepped up its preparations for Operation Overlord and as the Allies brought the German submarine threat in the Atlantic under control, the buildup in the United Kingdom accelerated quickly, overshadowing the allocation of resources elsewhere. But with such a substantial concentration of personnel and other assets in Asia and the Pacific from the outset, it was practically impossible for the Joint Chiefs to draw and maintain a clear distinction in priorities.