298. Memorandum From the Under Secretary of State (Katzenbach) to President Johnson1


  • Military Nuclear Cooperation with the United Kingdom

Before year-end, we must decide whether we want to exercise our option to terminate certain information exchanges under our 1958 Agreement with the United Kingdom on Military Nuclear Cooperation. We will not again have this option for another five years.

We have agreements for very limited cooperation in the nuclear weapons field with NATO and ten countries. The arrangement with the United Kingdom is unique, however, because it provides for exchanges of information relating to weapons design and manufacture and supply of nuclear materials for weapons.

The SIG, with the participation of the AEC, has reviewed our policy in order to determine whether changes in the 1958 arrangement would be in the United States interest at this time.2 It has concluded that:

  • —We should maintain the existing arrangement;
  • —We should, however, limit exchanges of weapons information and materials to what the British need to carry forward their program in nuclear weapons research and to maintain the effectiveness of their existing nuclear forces;
  • —We should not, in the absence of advance Presidential approval, encourage, or commit ourselves to support, any significant modification to existing British programs or any major new British programs.

Secretaries Rusk and Clifford and the AEC concur in the conclusions and recommendations set forth more fully below for your approval.


There is one issue which must be decided now, and a related question which should be considered but does not require a decision at this time.

  • First—Under the Agreement, we have the option, until December 31, 1968, to terminate Article II, which provides for the exchange of information on nuclear weapons and military reactors—in addition to [Page 633] the more limited information which we also exchange with most of our other NATO allies. If we exercise the option, these exchanges will terminate at the end of 1969. If we do not, we will not again have the option to terminate Article II for another five years. There is every reason to think the British want to continue exchanges in the nuclear weapons field. Congress does not need to act. A subsidiary issue is the extent to which we would continue the flow of information to the British assuming Article II is not terminated. The Agreement leaves that to our discretion.
  • Second—The related question is whether, if the British ask us, we should extend the 1959 Amendment on weapons materials and equipment exchanges to the 1958 Agreement. Under that Amendment, which does not expire until the end of 1969, we have been supplying the British with weapons-grade uranium, tritium, and other materials, and with non-nuclear parts of weapons. No decision is needed now. Undoubtedly, however, the British will propose a new Amendment that would keep open the option of continuing such exchanges. They will probably wait until early next year to approach us. In the unlikely event that they approach us this year, we could begin preliminary staff work but would tell them that a decision would have to be made by the next Administration. A new Amendment would have to be submitted to Congress for the statutory sixty-day waiting period before it enters into force.


The United Kingdom’s nuclear forces only marginally supplement our own. But the fact of the matter is the British consider a small nuclear deterrent to be better than none. They will require some further weapons information and materials merely to maintain its effectiveness. They are unwilling to give up their nuclear deterrent except in return for an effective European nuclear arrangement which would substitute for both the British and French national nuclear programs. As of now, no such arrangement is in sight.

Under these circumstances, unilateral termination by us would cause serious disaffection between our two countries, both major British parties being firmly committed to the retention of an independent British nuclear deterrent. It could also appear to be indirectly promoting France as the principal Western European country in the nuclear business.

On the other hand, it is true that the nuclear weapons arrangement is a symbol of our “special relationship” and therefore a factor of major significance in French attitudes toward British membership in the EEC. However, the British, rather than we, need to judge when this aspect of our relationship should be limited or terminated to meet their political objectives in Western Europe.

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Continuation of some cooperation in the nuclear weapons field will also permit us to monitor closely the work being carried out by the British and will help to assure that we receive the benefits of their technical advances.

We do not expect, however, that such benefits from British technical advances in the nuclear weapons field will be of more than limited value to us. For this, as well as for security reasons, we would not furnish information which reveals the vulnerability levels of United States missile systems.

Continuation of our cooperation with the United Kingdom in this field would not compromise our objectives of promoting the Non-Proliferation Treaty. The various U.S./U.K. Agreements do not provide for the transfer of manufactured warheads or their nuclear cores, but are confined to assistance in the manufacture of warheads. Such assistance among nuclear weapons states is not prohibited by the NPT.

The 1958 Agreement for Cooperation also provided for limited assistance to the United Kingdom in naval nuclear propulsion technology. Our obligations in this field will have been completely fulfilled by mid-1969, excepting reactor safety information, to be provided unilaterally by the United States, for the propulsion plant furnished earlier under the Agreement.

We do not anticipate that the British will request additional naval nuclear propulsion information, and there are no plans to provide them with additional assistance in this field. In any event, further information would not be provided without specific approval of the President. We have, however, signed a revision to the Agreement under which the United States will supply specific quantities of enriched uranium and other specified reactor materials for the British nuclear-powered submarine program, prior to December 31, 1979.


The SIG, with participation of the AEC, has concluded:

  • —The United States should not take steps to alter current arrangements on exchanges of weapons information. More specifically, the United States should not act to terminate Article II of the Agreement. However, it also should make no overtures concerning major new British programs or significant modification (e.g., the installation of MIRVs) to existing British programs.
  • —Accordingly, in response to British requests, we would, selectively, release that nuclear weapons information which the British need to maintain the effectiveness of their existing nuclear forces and to evaluate fully the alternatives available to them for improvement of these forces. (This could include selective information on hardening techniques, and information related to Poseidon technology.) We would [Page 635] also continue to exchange information in certain areas of research on weapons technology which offer a reasonable prospect of mutual benefit.
  • —If the British ask us, before January 20, to renew the 1959 Amendment on materials and equipment exchanges, we would tell them that a decision will have to be made by the next Administration. (Since this Amendment does not expire until the end of 1969, a decision is not needed now.) We would begin the preliminary staffing of a ten-year renewal of the Amendment—although, here too, we would limit our weapons assistance strictly to what the British need to maintain the effectiveness of their existing nuclear forces. We would also continue to exchange source, by-product, and special nuclear materials and non-nuclear parts or materials for research on atomic weapons.
  • —We would make clear to the British that the extension of present arrangements is intended to deal only with the framework for cooperation on weapons information and materials assistance; and that we reserve the right to evaluate any specific request in this area in light of all the factors and considerations at the time.
  • —We would be willing to limit or terminate our cooperation if the British decide their special relationship with us in the nuclear field prejudices their chances for entry into the European Economic Community.
  • —Any requests the British might make for information or materials or equipment for major new programs or significant modification to existing programs would be submitted to the President. This would include the question of whether to assist the British in the development and deployment of MIRVs for their Polaris missiles or to provide additional naval nuclear propulsion information.


That we not exercise our option, by December 31, 1968, to terminate Article II of the 1958 Agreement for Cooperation on Uses of Atomic Energy for Mutual Defense and continue that cooperation in accordance with the conclusions stated above.

If you approve, we will inform the Joint Committee on Atomic Energy of your decisions set forth above.3

Nicholas deB. Katzenbach
  1. Source: Johnson Library, National Security File, Country File, UK, Vol. 14. Secret.
  2. A copy of the SIG decision paper is in the National Archives and Records Administration, RG 59, SIG Files: Lot 74 D 344.
  3. An undated memorandum for the files by Bromley Smith, attached to the memorandum, reads: “S/S Ben Read informed that by not acting, the President understood he was deciding not to exercise our option to terminate our exchange of information with the British. BKS“