New Zealand Minister here  has told me his views regarding the control of the A.N.Z.A.C. area including the mainlands of Australia and New Zealand and how he thinks the mind of his Government will work.
I think you should know how the personality of Admiral King  may well react at that proposal. He tends to be very interested and conscientious regarding areas for which he is definitely responsible, and much less interested in areas for which he is not personally responsible. For instance, he makes little or no distinction in his mind between his responsibility for the Pacific area as a whole (exercised through his subordinate commanders at Honolulu) and his responsibility for A.N.Z.A.C. area (through Leary ). Under present conditions northern and eastern boundaries of the A.N.Z.A.C. area mean very little to him, and if A.N.Z.A.C. area command remains as it is he is likely to operate considerable United States naval forces (drawn from Honolulu) in or close to A.N.Z.A.C. area (as he has done lately) in addition to forces officially designated to A.N.Z.A.C. area.
On the other hand, he had little or no direct responsibility for A.B.D.A. area and as a result he took very little interest in it by way of naval reinforcements, much as he was pressed to do so.
I reflected these views (which I still have excellent authority for believing to be true) in my telegrams 245 and 383. 
Additionally if any supreme commander (even an American) of Australia and New Zealand and A.N.Z.A.C. area were to be interposed between King and Leary (in respect of A.N.Z.A.C. sea area) his interest and sense of direct responsibility for naval control of A.N.Z.A.C. sea area may diminish. If supreme commander were to be an American General (and strangely enough particularly if it were MacArthur ) I believe King's interest in A.N.Z.A.C.
area would be reduced. I realize that this may sound incomprehensible in existing circumstances but I believe it to be true.
In other words by the re-establishment of the united command in A.N.Z.A.C. area, unity of naval command in Pacific area as a whole may be jeopardized.