740.0011 European War 1939/10855: Telegram
The Ambassador in Japan (Grew) to the Secretary of State
[Received May 13—3:45 a.m.]
669. 1. I assume from the present trend of developments that war between the United States and Germany is conceivable.
2. If such a war should occur, Japan would be obligated by the provisions of article III of the Tripartite Alliance of September 27, 1940, to determine in consultation with her allies whether the United States was the aggressor, thus rendering operative the mutual assistance clause of the treaty.
3. Based on a careful estimate of official and public opinion in Japan, it is my belief that predominant influences including the Emperor, the Prime Minister, Baron Hiranuma, the majority of the Cabinet members and also the Japanese Navy, would be reluctant to incur war with the United States and would make every effort to find an interpretation of article 3 which would release Japan from the mutual assistance obligation, provided that this could be done without sacrificing honor and without losing face vis-à-vis the United States.
4. If future developments should lead the United States into war with Germany, it seems important that our Government should have in mind the foregoing considerations with a view to affording Japan, so far as might be feasible in such a contingency, some valid ground for declaring the provisions of article 3 not applicable. Should war with Germany ensue from a German attack on an American warship or other vessel, it would seem reasonable to assume that Japan would find that the provocation and casus belli had been given by Germany. If, however, the first shot were fired by an American warship, Japan’s obligation under article 3 might in good faith be called into effect.
[Page 188]5. The foregoing thoughts are of course all hypothetical and speculative but I believe they are worth considering.