It was in February 1944 that then Prime Minister Tojo Hideki (also Minister of the Army) and Naval Minister Shimada Shigetaro were jointly appointed as Chiefs of Staff of the Army and Navy, respectively. Such a breach of tradition in separating the civil and military administration of the armed forces presented an opportunity for the veteran Naval officers who wanted a quick end to the War to publicly criticize Tojo, criticism that is thought to have been one cause of the Cabinet's downfall. The research to date argues that the joint appointments were made for two reasons : one to overcome opposition between civil ministers and the military chiefs of staff, the other to fight the peace movement being conducted by the naval officers. While it would not be surprising that the peace movement that would be begin in earnest the following year was already brewing, what is puzzling is why Shimada would receive the joint appointment when no opposition existed between his ministry and the naval supreme command. Did Tojo and Shimada really begin to feel the threat posed by the peacenik naval officers? Or could there be some other political reason besides the peace movement that the conventional research has overlooked? In this article, the author focuses on opposition that arose within both the naval ranks and the supreme command, looking at such issues as the conversion of the navy into an air force, unification of the military supreme commands and the supreme command system itself, in order to show that the joint appointments were made to form a system of army-navy cooperation within the supreme command and avoid a change of government. Traditionally, both the Army and the Navy had their own air forces, which were funded on an equal basis. The Army and Naval chiefs of staff both insisted on more emphasis being put on their respective air forces in realizing the slim possibility of winning the War. Since both sides were convinced that funding allocation rates would determine the outcome of the War, the supreme command could not come to a decision about the military strength of the two branches. This resource mobilization problem then began to reverberate within the government and developed into an issue threatening the continuation of the present cabinet. The Emperor, who had given Tojo his vote of confidence, began to hint about a change of government and thus was not able to reach a political compromise over the opposition between the Army and Navy over military strategy. Consequently, the upper ranks of the Army, which was aimed at defending the home front and veteran naval officers who aimed at reviving the War came to odds over where the war front should be positioned. It was this opposition that led directly to the downfall of the Tojo Cabinet.