 The President of the United States , Franklin Roosevelt , and the Prime Minister of the United Kingdom , Winston Churchill , discussed the matter of command arrangements in the Pacific in Washington , D.C. , on 9 March . Roosevelt proposed that the world would be divided into British and American areas of responsibility , with the United States having responsibility for the Pacific , where there would be an American supreme commander responsible to the Joint Chiefs of Staff . Churchill responded favourably to the proposal , and the governments of Australia and New Zealand were then consulted . They endorsed the idea of an American supreme commander , but wanted to have some input into matters of strategy . 
