164. Editorial Note
When President Johnson approved Latchkey II on November 3, 1966, the AEC-DOD program consisted of eight underground nuclear tests scheduled for the second quarter of fiscal year 1967. (See Document 134.) Cabriolet, the first of a series of six nuclear cratering experiments under the Plowshare program was not one of these eight; its authorization still awaited final Presidential approval. The purpose of Cabriolet and other tests like it was to obtain basic technical information about cratering and the subsequent distribution of radioactivity that would be applicable to excavation of a trans-Isthmian canal. It was not until [Page 401] December 20 that Glenn Seaborg received a telephone call from Spurgeon Keeny that the President had approved going ahead with Cabriolet. There was, however, one caveat, as recounted by Seaborg: “there is to be a prior announcement of what we propose to do (spelling out the nature of the test, that it is peaceful in nature, that we see no problems with it, that it has to be done within the Limited Test Ban Treaty, etc., …).” (Seaborg, Journal, Volume 13, page 654.)
Cabriolet was scheduled to be set off on February 1, 1967, but was delayed for technical reasons, and rescheduled for February 10. However, on February 9, President Johnson abruptly changed his mind and decided to cancel Cabriolet for the present. Concerns were raised over Cabriolet’s potential to hurt the ongoing negotiations on the non-proliferation treaty and the Latin American nuclear free zone treaty, in both of which peaceful nuclear explosions were an important issue. After more discussions with Rostow in April regarding the rescheduling of Cabriolet, Seaborg received a telephone call on May 1 from Rostow informing him that he was to proceed with “the planning of both Cabriolet and Buggy.” However, Seaborg continued, “There was no commitment as to actually conducting the explosions—we were merely to plan—and there was to be no public announcement.” (Seaborg, Stemming the Tide, pages 333-334)