At lunch, the committee and its panel spread out among four tables. Lawrence, Oppenheimer, and Compton sat together with Byrnes, Stimson, and Groves. Prompted by Byrnes, Lawrence spoke up on an issue that had been left off the agenda, but that he had raised briefly during the morning’s discussion: how the bomb might be used against Japan. Lawrence proposed that the weapon be demonstrated to the Japanese “in some innocuous but striking manner, before it should be used in such a way as to kill many people.”78
The idea of a so-called demonstration of the bomb had been discussed earlier, at both Los Alamos and Washington.79 But Lawrence’s suggestion was the first time that it had been discussed at such a high level—or with such seriousness.80
Numerous practical objections to the scheme were immediately raised by others at the table. Stimson—who was suffering increasing anguish, his personal diary showed, from the daily destruction of Japan’s cities—doubted that casualties from the atomic bomb would be any worse than the masses of people killed by conventional bombing, including the recent B-29 fire raids upon Tokyo. Oppenheimer and Groves expressed similar skepticism that a demonstration could be “sufficiently spectacular” to compel Japan’s surrender.81 Byrnes himself worried that the Japanese, if warned of an impending atomic attack on their home islands, might move American prisoners of war into the target area. Cowed by this resistance, Lawrence did not argue the point. The entire lunchtime discussion had taken perhaps ten minutes.
Assembling afterward in Stimson’s office, the Interim Committee officially took up the question of the bomb’s use. Notes by Stimson aide Gordon Arneson left little doubt that, in Stimson’s mind at least, the issue was settled by meeting’s end:
After much discussion concerning various types of targets and the effects to be produced, the Secretary expressed the conclusion, on which there was general agreement, that we could not give the Japanese any warning; that we could not concentrate on a civilian area; but that we should seek to make a profound psychological impression on as many of the inhabitants as possible. At the suggestion of Dr. Conant the Secretary agreed that the most desirable target would be a vital war plant employing a large number of workers and closely surrounded by workers’ houses.82
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At Los Alamos that spring, Oppenheimer was becoming anxious to leave the lab. In a report to Groves on May 7, Oppie described the wartime laboratory as “singularly unsuited for peacetime perpetuation,” requiring a great change “in the way in which the Laboratory is set up and very probably an actual shift in its physical location.”83 Oppenheimer also let Groves know that he should start looking for a replacement: “In particular, the Director himself would very much like to know when he will be able to escape from these duties for which he is so ill qualified and which he has accepted only in an effort to serve the country during the war.”
The Scientific Panel gathered once again, at Los Alamos, on June 16. In the waning minutes of the last Interim Committee meeting, Stimson had asked the scientists to draft a memorandum on the future prospects for atomic research. The panel’s deliberations had just begun, however, when they were cut short by an urgent phone call from Stimson aide George Harrison, who asked for the scientists’ views on a more pressing issue: the use of the bomb against Japan.
Behind Harrison’s inquiry was a document that Compton and Chicago physicist James Franck had tried, unsuccessfully, to deliver to Stimson a few days before. The Franck report was a thirteen-page plea by Met Lab scientists for international control of the atomic bomb. Among its earnest recommendations was one which was highlighted, urging “a demonstration of the new weapon … before the eyes of representatives of all the United Nations, on the desert or a barren island.”84 Before Stimson responded to the Franck report, Harrison explained, he wanted the panel’s opinion. Hoping to do his own lobbying for the report within the panel, Compton had brought copies along with him on the train from Chicago.85
Lawrence led the reopened discussion of the demonstration. Although Fermi had remained mute on the subject before the Interim Committee, he evidently sided with Lawrence in this new debate.86 Ironically, Compton now spoke out against the demonstration—arguing that use of the bomb against a military target would result in a “probable net savings of lives.” Were the bomb not used, Compton asserted, “the world would have no adequate warning as to what was to be expected if war should break out again.”87 When Lawrence persisted, Compton hinted that Ernest’s views on the subject were unduly influenced by the latter’s fond memories of Japanese physics students at Berkeley.88
But it was Oppenheimer who made the final, telling argument against the demonstration. His objections were a reprise of the points he had raised at the meeting on May 31: The bomb was not certain to work, and a dud might even be used against us by the enemy; Japanese defenses would be alerted by a warning, and POWs possibly moved onto the target. Most important, no conceivable demonstration of the bomb could be as compelling as its actual combat use against what Groves and the army were calling “built-up areas”—that is, cities.89
This time, Lawrence appears to have remained resolute, refusing to back down.90 Thus the memorandum that Oppenheimer sent to Stimson from Los Alamos acknowledged that the views of the scientists on the use of the bomb were “not unanimous: they range from the proposal of a purely technical demonstration to
