149. Memorandum From Secretary of State Rusk to President Johnson1
SUBJECT
- Cabriolet Nuclear Cratering Experiment
Recommendation:
I recommend that you authorize the AEC to conduct the Cabriolet test, without prejudice to the decision on any subsequent cratering experiment in the Plowshare series which should be evaluated and decided on the merits at the time and in light of experience with Cabriolet.
Problem:
The AEC is requesting approval to conduct Cabriolet, a 2.7 kiloton nuclear cratering Plowshare experiment, about December 1, 1966, in Nevada. Some radioactive debris will be released into the atmosphere, since the object of the experiment is to produce a crater. There is no health hazard involved, but a detectable amount of radioactive debris can be expected to drift from Nevada and cross the Canadian border. The consensus among proponents and opponents is that there is a 50-50 chance that a certain amount of debris would be picked up and identified by the Canadians as coming from Cabriolet; a much slighter chance that detection would occur when the debris had proceeded beyond Canada.
Pros
The main arguments AEC and others have cited for conducting Cabriolet are:
It would permit continued U.S. technical progress in nuclear excavation, which we have indications the USSR is also pursuing.
It would help maintain the credibility of the nuclear excavation option for a sea level Panama Isthmus Canal.
It would furnish data necessary to support the Atlantic-Pacific Interoceanic Canal Study Commission program, and permit tentative planning of follow-on experiments needed if the Commission’s reporting schedule to you is to be kept.
It would allay Joint Atomic Energy Committee concern that we seem to have stopped conducting a nuclear excavation program, whereas testimony to the Congress in connection with the Test Ban Treaty, as well as subsequently, indicated that cratering experiments could and would continue to be conducted without violating the Treaty or future amendments thereto.
Cons
The main arguments which ACDA and others have made against conducting Cabriolet are:
There is an even chance that it would expose the U.S. to a charge of violating the Test Ban Treaty by depositing across our border detectable, identifiable radioactive debris from a U.S. test.
Consideration of Cabriolet should not be separated from the decision to be made on the overall Plowshare program. To be meaningful, [Page 364] Cabriolet would have to be followed by other and larger shots, thus increasing still further the probability of charges of Treaty violation.
If we are charged publicly with a violation of the Treaty as a result of Cabriolet, it could hamper consideration of other Plowshare peaceful explosion proposals, such as that suggesting the creation of an international entity to offer Plowshare services to the world.
The ACDA General Advisory Committee on Disarmament, headed by John McCloy, expressed a formal consensus without dissent on September 13, that it opposed the conduct of Cabriolet, because of “prejudice to non-proliferation” and concern about a conscious violation of the Test Ban Treaty. The Committee includes men such as I.I. Rabi, Herbert York, John Cowles, George Kistiakowsky, Roger Blough and Tray Post.
Discussion:
This problem has been considered fully and carefully over a considerable period of time at the highest levels of government. It is my view that the advantages of proceeding with Cabriolet outweigh the risks.
- Source: Department of State, Central Files, AE 6 US. Secret. A September 16 cover memorandum from Benjamin H. Read to Rusk reads as follows: “Pursuant to your commitment to the President at lunch last Tuesday, I have had the attached memorandum prepared setting forth the pros (from the AEC papers) and the cons (from Bill Foster’s memoranda) and your recommendation that the President authorize the experiment to proceed. ACDA has approved the con portion of the memo and Alex Johnson has approved the whole memo. Recommendation: That you sign the attached memorandum.” A typed note on the source text states that the memorandum was “approved by the President. W. Rostow’s office notifying AEC of approval.”↩
- Printed from a copy that indicates Rusk signed the original.↩