He was the United States ' first de facto Chairman of the Joint Chiefs of Staff ( not his official title ) .
Chairman also presided over the United States delegation to the Combined Chiefs of Staff , when the United States and British staffs worked together .
He was the United States ' first de facto Chairman of the Joint Chiefs of Staff ( not his official title ) and he also presided over the American delegation to the Combined Chiefs of Staff , when the American and British staffs worked together .