Arthur James Balfour to Colonel House

Following from Balfour for House.
Since my return to England the question which you discussed with Drummond of a possible naval agreement between the United States and Great Britain in order to allow of extended building of destroyers and light-craft instead of capital ships already authorized by the United States programme has been carefully considered by the War Cabinet.
In view of submarine menace ADMIRALTY attach the highest importance to building by your Government of maximum number of destroyers and light-craft; indeed, it is not too much to say that this may have a great effect on ultimate result of war. I need hardly tell you that Cabinet were and are profoundly attracted by the idea of any defensive arrangement with the United States. They were clear that, with or without guarantee, popular opinion in this country would undoubtedly force us to go to the assistance of the United States if she were attacked by Japan. At the same time we realize that a private and informal recognition of this would hardly be sufficient to allow the United States Government to forego building capital ships, in view of widespread popular mistrust of Japan's intentions, though in opinion of our Naval authorities the United States has nothing to fear from Japan, since with some important exceptions the United States fleet is much superior to Japan numerically and otherwise. In larger capital ships, both constructed and under construction, with exception of battle cruisers, the United States has already a considerable preponderance. On the other hand their number of fast light cruisers is in the opinion of our naval authorities quite inadequate for operations of a fleet of dimensions of that of the United States, while their superiority in destroyers over Japan is also insufficient. The most urgent requirements of the United States Navy as against Japan are in fact for light cruisers, destroyers, and anti-submarine craft, and, with the exception of the battle cruisers, it would seem a waste of resources for the United States Government to build more capital ships.
The main difficulty of an arrangement between our two countries is that if Great Britain undertakes to give Naval aid to the United States in future possible war Japan will probably consider the agreement is directed against her. We think the spirit of our treaty with Japan would make it incumbent on us to inform her of what we were doing, and we assume the idea of secrecy must be excluded.
Announcement in Japan of such an arrangement must inevitably raise highly dangerous discussion, and would certainly be interpreted by Japan primarily aimed at blocking her aims in China, in the Pacific and Far East generally, with the result that she might throw herself in the arms of our enemies, in which event a most perilous situation would be created.
I have therefore endeavored to find a formula which would, while overcoming these difficulties, assure the United States of absolute protection at the end of the war either against the German Fleet– which as you recognized is a real peril– against Japan or against both; and only method of so doing appears to be to endeavor to associate Japan from the beginning with the new arrangement. This would have triple effect of allaying Japan's fear, of engaging Japan's support, and of adverting treaty as a protection against Germany; but, if Japan is brought in and if Germany is marked out as a power against whom precautions have to be taken, ought not France to join in, and, if France, also Italy? Russia might perhaps be excluded on grounds of geographical position, though I think this would be a mistake.
I do not know whether you will consider such an arrangement as is here suggested practicable at the present moment, but if so it would seem to afford, besides everything else, a foundation for a maritime league to ensure peace strongly.
The following are actual terms of arrangements I would suggest:“That, in view of diverting Government ship-building in naval yards of the United States from construction of capital ships to that of vessels suitable for anti-submarine warfare, the Governments of the United States, Great Britain, France, Italy, Russia and Japan engage singly and severally to assist each other against any maritime attack for a period of four years after conclusion of the present war."Should President like this scheme I am prepared to take any steps he may desire to help in bringing it to fruition. If he sees objection to it I would endeavor to find some acceptable alternative.