British Ambassador [1] saw the President [2] today. Following is
British Ambassador's telegram to London practically textually.

(1) President's information was that Japanese Government was a
good deal disturbed by his return. He told me that the Japanese
had returned to the subject of the interim arrangement, and Hull
[3] had replied to the effect that the interim arrangement was not
possible on a unilateral basis which was the basis on which
Japanese were proceeding inasmuch as they were continuing moving
troops all the time.

(2) President told me that he thought we should both continue our
air patrol for further period which he did not specify. He had
also given orders for three United States submarines to watch
likely waters for sake of information. They would not take
offensive action but would act if attacked.

(3) He then discussed Japanese reinforcement of Indo-China and
said he had been considering the possibility of some concerted
action parallel with us. He thought, however, that wiser course
was to begin by making communication to Japanese in form of a
question which he proposed to instruct Sumner Welles to give to
Japanese this evening or tomorrow morning on lines enquiring where
Japanese troops now moving south were going to, and if they were
going to Indo-China, for what purpose. [4]

(4) I asked what would be next step since Japanese reply would
certainly be either puzzling or evasive seeing that there could be
no possible legitimate reason for such reinforcement of Japanese
strength in Indo-China.

(5) President said he thought it was of great importance that
British and American Governments should be clear in their minds as
to what they did in various hypothetical situations that were
likely to arise.

(6) He wished me to ask you what the British Government would do
in the event of (a) Japanese reply being unsatisfactory, further
reinforcements not yet having reached Indo-China; (b) reply being
unsatisfactory further reinforcements having in the meantime
reached Indo-China; and (c) Japanese attack on Thailand other than
attack on Kra Isthmus, having in his mind such Japanese pressure
on Thailand as to force concessions to Japanese detrimental to
general position.

(7) Grateful for prompt replies to above. I think whatever action
you are prepared to take, President would probably support. Method
of support is presumably for staffs but he spoke all the time of
United States air strength in Philippines and long distance naval
blockade 'which of course means shooting'.

Whole tenor of his conversation, though he did not actually say
so, was in sense that we should both recognise any of these
hypothetical actions to be clear prelude to some further action
and threat to our common interests against which we ought to react
together at once.

At one point he threw in an aside that in the case of any direct
attack on ourselves or the Dutch we should obviously all be
together, but he wished to clear up matters that were less plain.

(8) In reply to my query as to the British forestalling the
Japanese in the Kra Isthmus, and as to what would be American
reaction to such an action on our part, the President said that we
could certainly count on their support [5] though it might take a
short time, he spoke of a few days, to get things into political
shape here.

In this connection he told me that they had information that
someone in the Japanese Embassy, Bangkok, had advised Tokyo to
make the first attack on British territory just south of the
Malay-Thai boundary, the argument being that this would
immediately oblige us to occupy position on the isthmus in Thai
territory and give Japan the advantage of making us the first to
commit an aggression against the Thais.

He said that if we could get the Thais to invite us it would
obviously be a good standby, but we must clearly do what strategic
necessity dictated anyhow.

(9) From various indications, including information that
discussions are proceeding between the Japanese and Germans about
the distribution of rubber from Indo-China, he has little doubt
that there is complete understanding between Berlin and Tokyo and
that the Japanese are playing a game stalling for time while
proceeding with their own policy at the dictation of the Axis. He
was quite clear that there was nothing to be made of any idea of a
standfast truce.

(10) He has an idea of sending a communication direct to the
Emperor which he said had been the only thing that had worked at
the time of the 'Panay' incident. [6] Such a communication would
be friendly but would make plain that if the present Japanese
policy continued war must result.

He is, however, suspending this for the present.

(11) He wished me to convey the suggestion that we should give the
Thais an undertaking if they resisted either Japanese attack or
infiltration that we would respect and guarantee for the future
their full sovereignty and independence. For constitutional
reasons the United States could not guarantee, but such an
undertaking on our part would be wholeheartedly supported by the
United States. Presumed the Dutch would also agree.

He thought that this might be very valuable against Japanese
propaganda or intimidation.

CASEY