45 Mr R. G. Casey, Minister to the United States, to Department of External Affairs
Cablegram 634 WASHINGTON, 14 August 1941, 12.35 a.m.
Reference Prime Minister's  telegram No. 91. 
I saw the Secretary of State  today and made clear to him the degree of importance that you put on Thailand. I said that whilst it was perceived that joint British-American statement to Japan would probably be necessary to deter her from further southward expansion with any certainty, yet, although no decision had yet been made, your minds were moving in the direction of a forthright warning to Japan even if United States was unable to be associated with such a warning, and that you were moved to consideration of such a serious step by the realization that the pass would virtually be sold in any event if Japan were to become installed in Thailand. I said that you were in telegraphic discussion with Britain on the above and that, whilst I had no instructions to speak to him officially on matters, I thought he would wish to know how your minds were working so that he might advise the President  immediately on his return of the seriousness with which you regard the Thailand situation. The Secretary of State said that he would discuss with the President on his return on August 15th.
The British Ambassador  and Duff Cooper  were present at the above conversation.
I subsequently saw the Secretary of the Navy  and spoke to him on similar lines to the above. He said that he and some of his colleagues in the Cabinet had been advocating to the President that joint British-American stand against any further Japanese moves south or west from Indo-China was absolutely essential if war in the Far East were to be averted and that they proposed the pursuance of this vigorously with the President on his return.
Colonel Knox needs no stimulating on this.
Apart from above, I pursued the question of further air and submarine reinforcement of Philippines with Secretary of Navy which he said he would investigate.
No doubt it will have occurred to you that what has taken place at Vichy may mean the French fleet being made available for the Axis  and that Japan may be counting upon this to be sufficient to stop reinforcement of Singapore by British capital ships. This possibility is clearly in mind of the Secretary of Navy who mentioned the possibility of United States having to move some of the naval strength from the Pacific to the Atlantic in the future.