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157 Lord Cranborne, U.K. Secretary of State for Dominion Affairs, to Mr John Curtin, Prime Minister

Circular cablegram M418 LONDON, 3 December 1941, 9.57 p.m.


Following for the Prime Minister.

My circular M.412. [1]

After consideration of Lord Halifax's account of his discussion
with the President the following reply is being despatched to Lord
Halifax this evening. Text begins.

1. We entirely agree with President Roosevelt that we and the
United States Government (and the Netherlands Government) should
be clear as to what action we shall respectively take in the
various situations likely to arise.

2. Of the hypotheses in paragraph 6 of your telegram the first two
seem to us for practical purposes indistinguishable. [2] All of
our information goes to show that reinforcements have been
arriving for some time and are still continuing. The only question
therefore appears to be what we should do if the Japanese reply to
President Roosevelt's enquiry is unsatisfactory. We feel that the
proper reaction would be simultaneous warning to Japan by the
United States, the Dutch and ourselves, to the effect that if she
uses Indo Chinese territory as a base for further aggression she
will do so at her peril. If such warnings are given it is
necessary to be clear as to the action which we shall take if they
are ignored. We read the President's assurance of support recorded
in paragraph 8 of your telegram [3] to mean armed support and on
this assumption we should ourselves be prepared to put into effect
the operation referred to in my circular M.4064 if there were a
direct Japanese attack or threat of immediate attack on Kra
Isthmus. Under hypothesis (c) the threat to Singapore might be
less immediate, but we should still think it wise to put into
operation the same plan provided that we had a similar assurance
that we would have the armed support of the United States if our
action resulted in hostilities with Japan. If the President wishes
to suggest any other form of action in which he would be disposed
to participate, we should of course be glad to consider it. We
note particularly the President's statement that in any direct
attack on ourselves or the Dutch we should all be together. We
fully endorse this statement.

3. We have already been considering the possibility of some
arrangement with the Thai Government under which our entry into
Kra Isthmus at whatever stage it might take place would be by
their invitation. The difficulty at present is that we are not
militarily in a position to give direct assistance to the Thai
Government in the protection of the rest of their territory. The
proposal to occupy a very small part of Kra Isthmus is therefore
unlikely to appeal to them and we fear that the same applies to an
undertaking from us to guarantee their ultimate full sovereignty
and independence. It would, we feel, be asking a good deal of them
to expect them to accept virtual certainty of partial extinction
in order to ensure their ultimate independence.

4. The Thai Prime Minister [5] has forcibly represented to us that
the only way to save Thailand is by a public warning to Japan by
the United States and ourselves that if she went to war with
Thailand she would find herself at war with us both as well. If he
knew that a warning of the type suggested in paragraph 2 above had
been delivered even though it were not made publicly his outlook
might change. We feel however that any communication to him about
our plans in Kra Isthmus would be useless until such a warning has
been delivered and there is in addition very great risk of leakage
to the Japanese. For the moment we are confining our actions to
informing Sir J. Crosby [6] of our plan so that he may be able to
make a communication at short notice.

5. We would propose to make it clear in any such communication or
in any announcement which might accompany our operation that we
should restore in full to Thailand any territory which we might
occupy and that our aim is to ensure full independence,
sovereignty and territorial integrity of Thailand. Text ends. [7]

1 Dispatched 2 December. On file AA : A981, Japan 185B, iii. It
repeated the text of a cablegram received from Lord Halifax (U.K.

Ambassador to the United States). Halifax's cablegram had already
been conveyed to the Commonwealth Govt 'practically textually' by
R. G. Casey, Minister to the United States. See Document 152.

2 See Document 152, paragraph (6).

3 See ibid., paragraph (8).

4 Document 139.

5 Maj Gen Luang P. Pibulsonggram.

6 U.K. Minister to Thailand.

7 Casey reported on 4 December (cablegram test on file AA : A981,
Japan 178) that Halifax had communicated the above to Roosevelt
who had reacted favourably. He had assented to occupation of the
Kra Isthmus, commented that if the Japanese attacked the Burma
Road through Thailand or in Burma 'the issue would be clear' and
had confirmed that 'support' (see paragraph 2 of this Document)
did mean 'armed support'. The President recognised the difficulty
of making any advance arrangement with Thailand but suggested both
a private communication to the Thais and a public declaration that
the United Kingdom had no intention of invading Thailand but was
concerned to see her sovereignty and independence preserved.

[AA : A981, JAPAN 178]
Last Updated: 11 September 2013
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