Roosevelt Papers

Aide-Mémoire Initialed by President Roosevelt and Prime Minister Churchill1

top secret

Tube Alloys

Aide-Mémoire of Conversation Between the President and the Prime Minister at Hyde Park, September 18, 19442

The suggestion that the world should be informed regarding Tube Alloys, with a view to an international agreement regarding its control and use, is not accepted. The matter should continue to be regarded as of the utmost secrecy; but when a “bomb” is finally available, it might perhaps, after mature consideration, be used against the Japanese, who should be warned that this bombardment will be repeated until they surrender.
Full collaboration between the United States and the British Government in developing Tube Alloys for military and commercial purposes should continue after the defeat of Japan unless and until terminated by joint agreement.
Enquiries should be made regarding the activities of Professor Bohr and steps taken to ensure that he is responsible for no leakage of information, particularly to the Russians.
F[ranklin] D R[oosevelt]
W[inston] S C[hurchill]
  1. Some of the background for the inclusion of the third paragraph in this aide-mémoire appears from a memorandum of September 22, 1944, by the Director of the Office of Scientific Research and Development (Bush) concerning a conference with Roosevelt which Bush had attended on that date at which Leahy and Cherwell were also present Bush recorded:

    “The President stated that Mr. Justice Frankfurter had visited him a few weeks ago and expressed himself as very much worried about the future handling in the post-war period of matters pertaining to the secret project. The President apparently professed ignorance of what Frankfurter was talking about, although do not know how far this went, and I certainly gained the impression that the President did not tell Frankfurter any more than he knew when he came. Frankfurter insisted that Bohr should see the President, as he and Bohr had discussed the future state of the world from this standpoint and Bohr had some very striking ideas. This was apparently arranged and the President had seen Bohr for a short time and listened to him. The President, however, was very much disturbed in regard to security and wished to know how far Bohr had been taken into the matter, whether he was trusted, and also how Mr. Frankfurter happened to know anything about the subject whatever. Lord Cherwell traced the history of Bohr’s escape from Denmark, his introduction to this country, and so on. He stated that Bohr had similarly seen the Prime Minister after having insisted on doing so in Britain and had told him his ideas about future handling of this subject. These ideas, I believe, revolve about immediate disclosure of the subject, its use as a threat against Germany, and similar matters, and also a control by the British and Americans of the subject after the war, and I judge the maintenance of a peace by the Anglo-Americans on this basis. I then traced the way Bohr had been introduced into this country and in particular the care that had been taken to be sure that he was handled in such a manner that we became sure of his discretion before introducing him to parts of the project Both Cherwell and I brought out the fact that he was a very important physicist who had been able to contribute and also that he had given us some ideas as to what was going on in Germany that were quite valuable. It also appeared in this discussion that Bohr had been invited by the Russians to visit Russia but had declined.” (A.E.C. Files, Historical Document No. 185)

    For further information on Bohr’s views and the manner in which they were brought to Roosevelt’s attention through Frankfurter, see Liva Baker, Felix Frankfurter (New York: Coward-McCann, 1969), pp. 271-278.

  2. This aide-mémoire was initialed in duplicate. On the copy kept by the British Government there is the following marginal manuscript notation at this point by Churchill’s Principal Private Secretary: “actually 19th J[ohn] M[iller] M[artin].” Concerning the circumstances in which Churchill sent Stimson a photocopy of the British original of the aide-mémoire on July 18, 1945, see Foreign Relations, The Conference of Berlin (The Potsdam Conference), 1945, vol. ii, p. 1370.