Reference P. M. Dept. telegram 140.  Situation at present is that Far Eastern situation is largely if not entirely in the hands of the President who is said to be still working on his proposed message to the Japanese Emperor. As I understand it this message will have some sting in it, but will not in itself constitute the 'warning'. Dependent on the terms of the Emperor's reply, the President will then send his warning and presumably warnings of all the rest of us will follow.
As to an American assurance to Thailand, State Department has been emphasising to the President the constitutional difficulty of such a step.
Secretary of State  has been trying to get the United States army and navy to show naval and air activity in the Gulf of Siam in order to hearten Thailand.
The President has to watch out that his activities, prior to the Far Eastern situation reaching a breaking point, do not enable his opponents here to say that 'the United States is acting in advance as if already an ally of Britain' which would increase his political difficulties.
I have consulted the British Ambassador  who does not believe there is anything immediate that we can say or do to advantage.