Captain William R. Hall, Director, Intelligence Division, to Imperial War Cabinet
Unofficial copies of the Anglo-Japanese treaties are attached for reference.
Each of the three Treaties has a clause safeguarding the Alliance against outside Treaties which might compromise the amount of support our Ally is entitled to expect from us.
The existing Treaty and the proposed Treaty are both “defensive” treaties which is probably the ground of Mr. Balfour’s claim that there is no logical incompatibility but it leaves us on the fence when any question arises between America and Japan to judge which is the aggressor and which the aggrieved.
During the first fortnight of June America sent a Note to China giving advice on her internal affairs which was strongly resented by Japan as poaching on her preserves: Japan could interpret this as aggressive action touching her interests in China and so claim our support under the treaty.
Japan is now going to be consulted and she will see what is the real underlying reason for any Agreement. This will be most inopportune at a moment when we are trying to get her to help us with requisitioned tonnage, quoting as an argument the spirit of our Treaty with her, the case not being covered by the letter.
Source Note: TDS, UK-KeNA, Adm. 137/1436.