An established theater command sidelines MacArthur

The proposed commander would hold unusual political weight because Britain, Australia, New Zealand, and India all depended on the joint arrangement. When MacArthur retreated toward Australia, an existing theater headquarters led by an admiral of the fleet would offer Roosevelt an alternative coalition commander. The British Empire officer would already possess a functioning multinational staff and senior relationships with the dominions. MacArthur might therefore remain an American army commander rather than becoming supreme commander in the Southwest Pacific. The posting would also likely replace Mediterranean command as the senior naval route toward becoming First Sea Lord.