711.94/5–2641
Memorandum by the Adviser on Political Relations (Hornbeck)
On May 14 and on May 19 Mr. Matsuoka expressed to Mr. Grew95 the opinion that if the United States convoyed ships to England and if [Page 225] some of our ships were sunk by the Germans and if war between Germany and the United States ensued Article III of the Tripartite Pact would come into force and it would mean war between the United States and Japan.
Comment: Today the Japanese are cooperating with the Germans in strenuous diplomatic effort to delay or prevent the giving by the United States of effective aid to Great Britain. If and when the United States is drawn into war with Germany, the Japanese will cooperate with the Germans toward preventing defeat of Germany and therefore toward preventing victory for (Great Britain and) the United States. This may or may not go to the extent of military operations by Japan against Great Britain and/or the United States; but, whether or not it goes that far, it will in my opinion—regardless of any pledges which Japan may have given, to her allies, to the United States, to China—be done.
- See telegrams No. 673, May 14, 5 p.m., from the Ambassador in Japan, Foreign Relations, Japan, 1931–1941, vol. ii, p. 145, and No. 707, May 19, 10 p.m., from the Ambassador in Japan, ante, p. 204.↩