Piercing the Fog - Air Force Historical Studies Office

Planning the Defeat of Japan
seemed less appealing with the passage of time. With these factors in mind,
Truman approved the use of the weapon late in July 1945.74
The initial decision by the president and Stimson to drop the atomic bombs
was not made on the basis of intelligence information either provided by or in
the possession of the AAF. It seems to have grown from the running course of
events. Material on hand in the JTG provided the basis for assessing the
prospective targets and preparicg for postattack surveys of the cities bombed.
Descriptions of this course of events given by both General Groves and
Secretary Stimson were remarkably alike in that regard. Senior government
officials, having presided over the expenditures of billions of dollars and the
creation in several states of technical and scientific complexes unrivaled
anywhere, assumed all along that such a weapon, if created, would be used
against an enemy power. Probably the only person who could have stopped the
use of the atomic bomb during the last weeks before its delivery was the
president, and Truman saw no compelling reason to do so in light of the bitter
fighting that many thought would last well into 1946. Quite the contrary;
Truman, Stimson, and Marshall were deeply concerned about the human cost
of an invasion and the subsequent fighting. Truman remarked during a meeting
with the JCS on June 18, 1945, that he “hoped that there was a possibility [by
using the bomb] of preventing an Okinawa from one end of Japan to another.””
Admiral William D. Leahy, for most of the war President Roosevelt’s personal
representative to and a member of the JCS, was equally cautious, fearing that
the Americans would suffer as many as 268,000 casualties in fighting for the
Japanese home islands (after refined intelligence of Japan’s home defenses
became available, the medical planners’s estimate for treatable casualties-not
including dead-rose to over 394,000, just for the invasion of Ky~shu).~~
The question of whether or not the atomic bomb’s use was necessary to end
the war without an invasion of Japan has never been settled and in all probabil-
ity can never be. Influential arguments supported the bomb’s use: in Secretary
Stimson’s words, an invasion would “cast the die for a fight to the finish”; use
of the bomb was essential to save the lives of Americans who would have to
bear the brunt of the effects of the landing and fight across the enemy homeland
in terrain favorable to the Japanese defenders. Strong arguments also opposed
use of the weapon: Japan had sent peace feelers to the Soviet Union seeking
Stalin’s intercession to end the war, and the United States knew of the Japanese
government’s position through reading of MAGIC decrypts. ULTRA had
indicated the military collapse of Japan and the military leaders’ understanding
of their country’s peril. But ULTRA-based analyses could not predict enemy
actions in so desperate a situation.”
Many of the men deciding the issue struggled with questions of military
usefulness and moral, ethical, and political implications of the bomb’s use.
Many had serious doubts. Stimson wavered repeatedly; he clearly saw the
atomic bomb as more than just a new weapon that could cause a bigger blast.
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