Authors: Brian Van DeMark
FDR’s death shocked Szilard and the entire nation. Vice President Harry S Truman now assumed the burdens of commander in chief
in a war that—especially against Japan—was growing fierce and pitiless. Between February and March 1945, three Marine divisions
had slugged their way across Iwo Jima, a western Pacific island of volcanic ash, rock, and stinking sulfur fumes. The island’s
21,000 Japanese defenders meant to make its conquest so costly that Americans would recoil from invading their homeland. The
battle for Iwo Jima became a nightmare of relentless attacks and swarms of flies feeding on dead flesh. One Marine despaired,
“They send you to a place and you get shot to hell and maybe they pull you back. But then they send you right up again and
then you get murdered. God, you stay there until you get killed or until you can’t stand it any more.”
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Five weeks of fighting on Iwo Jima cost the Marine Corps nearly 7,000 dead and 22,000 wounded out of 60,000 committed—the
highest casualty rate in Marine Corps history. Its three divisions had to be rebuilt with teenage replacements. The Japanese
on Iwo Jima perished almost to a man, having inflicted more casualties in killed and wounded than they suffered for the first
time in the war.
Things would be even worse during the Battle of Okinawa between April and June, when Americans encountered the most savage
Japanese resistance of the war. Kamikaze suicide bombers slammed into navy ships offshore, turning destroyers into flaming
junk heaps manned by bloody remnants of their crews. The kamikaze attacks were alien and terrifying; they confirmed for Americans
the extent of Japanese doggedness and desperation even as the United States ground down Japan’s war machine. The navy suffered
10,000 casualties, half of them killed. Fighting on the island was a slaughter. Before it was over, more than 100,000 Japanese
soldiers and another 100,000 native Okinawans had perished. The U.S. army lost 40,000 men, a fourth of them killed in action.
Thousands of Americans and Japanese were being killed on the beaches and in the jungles of the Pacific every week.
In the skies over Japan, giant American B-29 bombers were running massive raids against cities, wiping them off the map, one
after another, like the wrath of God. The results were devastating and appalling. Twenty-two million Japanese—30 percent of
the country’s entire population—were rendered homeless by fire raids that razed 178 square miles of densely populated urban
areas. The fire raids inflicted 2,200,000 civilian casualties, including approximately 900,000 killed. The number of Japan’s
civilians killed exceeded its combat casualties of approximately 780,000.
Nothing illustrated the escalating violence of the Pacific War—and the declining restraint of its combatants—more vividly
than the B-29 fire raid against Tokyo in March 1945. At the start of the war, Roosevelt had entreated all combatants to refrain
from bombing civilians and recalled with pride that “the United States consistently has taken the lead in urging that this
inhuman practice be prohibited.”
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Now America launched a thousand-plane bombing raid deliberately designed to burn Japan’s capital city—and its civilian inhabitants
who lived there, crowded in wood-and-paper houses—to ashes.
Shortly after midnight on March tenth, residents of Tokyo peered out of their air-raid shelters and saw an eerie sight above
the city. Reflecting spectral colors from searchlights, hundreds of B-29s descended slowly, their bomb bays filled with six-pound
incendiary bomblets that spewed burning gelatinized gasoline that stuck to its targets and was inextinguishable. The bomblets
were intended to set the city afire and they did, splashing a flaming dew across wooden roofs and spreading fire everywhere.
Wind whipped scattered fires into furnaces of flame, a thermal hurricane that jumped streets, firebreaks, and canals at dizzying
speed. It acted like an enormous bellows, superheating the air to eighteen hundred degrees Fahrenheit. B-29s in later attack
waves spotted the growing cauldron while still far out at sea. As they flew over the boiling city, they bounced violently
as thermal updrafts from the vast and intense conflagration below knocked them about like paper airplanes. At six thousand
feet the heat was so intense that crews had to don oxygen masks to breathe. Even at this altitude, American airmen could smell
the soot and the burning flesh and vomited. A bombadier who flew above Tokyo that night remembered it as “the most terrifying
thing I’ve ever known.”
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Fire was not the only danger to Japanese civilians below. Superheated vapors rushing ahead of the flames killed or knocked
victims unconscious even before the fires reached them. Death came in many agonizing ways: oxygen deficiency, carbon-monoxide
poisoning, radiant heat, direct flames, and crushing stampedes. Canals and ponds through the city offered no relief; luckless
bathers were boiled alive or drowned as frantic crowds pushed them down in the superheated water. When the raid was over,
sixteen square miles had been burned out, one million people were homeless, and upward of 100,000 had perished. Only a few
sounds could be heard across the smoking moonscape of vast desolation the next morning: the groaning of victims with burned
lungs, the desperate calls for missing loved ones.
In an eerie—almost unbelievable—irony, on the same night as the massive B-29 fire raid on Tokyo, a high-altitude Japanese
balloon dangling two small incendiary bombs, after drifting across the Pacific Ocean on the jet stream, flukishly fell on
the Hanford nuclear reservation in remote south central Washington state. Ropes dangling from the balloon became entangled
in the electrical line feeding power to the building housing a nuclear pile. The pile had to be shut down at once, though
the power was restored a few hours later. It was this plant that was producing the plutonium that would devastate Nagasaki.
The Manhattan Project, like the war itself, was nearing its climax in the spring of 1945. The project had proceeded with Roosevelt’s
steadfast support, and although the responsibility was now Truman’s, the new president was constrained by the choices of his
prestigious predecessor. FDR had refused to broach the subject of international control with Stalin and had indicated his
intention to use the bomb to help win the war. Such policies molded the outlook of his successor, who was uninformed, unprepared,
and unsure of himself. Truman had met with FDR only
twice
between his inauguration as vice president on January twentieth and Roosevelt’s death on April twelfth—both times on trivial
matters. He was unaware of the agreement FDR and Churchill had reached at Hyde Park. Nor did Truman’s experience as chairman
of the Senate Committee to Investigate the National Defense Program prepare him to deal with the Manhattan Project, because
the secret had been withheld from him. In a subtle but important respect, the new president was at the mercy of decisions
already made and events rapidly unfolding.
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To compensate for his inexperience, his ignorance, and his anxiety to do well the job suddenly thrust upon him, Truman relied
heavily on his inherited advisers, particularly Secretary of War Henry Stimson and James F. Byrnes, a close confidante of
Truman who had been his mentor in the Senate, a Supreme Court justice, and war mobilization director under Roosevelt. The
race for the atomic bomb was consuming an increasing amount of Stimson’s time by April 1945, even as the war in the Pacific
grew fierce and the weight of his seventy-seven years left him in need of rest every afternoon; and as he became more deeply
involved with atomic matters, he began to ponder and reflect.
Stimson inclined toward the bomb’s wartime use and to hold the secret of the bomb as a reward to induce Stalin’s cooperation.
Although he knew the Soviets were spying on the project, he did not believe they had acquired any crucial information; and
while he was troubled about the possible effect of continuing to keep them officially uninformed about the enterprise, he
believed that it was essential, as he wrote in his diary at the end of 1944, “not to take them into our confidence until we
were sure to get a real quid pro quo from our frankness.” Stimson had no illusions about the possibility of keeping such a
secret permanently, but he did not think “it was yet time to share it with Russia.”
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Stimson did not intend to threaten the Soviet Union with the new weapon, but he expected that once its power was demonstrated,
the Soviets would be more cooperative about postwar issues.
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At the end of Truman’s first Cabinet meeting, hastily convened after he was sworn in on April twelfth, Stimson stayed behind.
He would spell out the details later, he said, but before departing he wanted to inform the new president of “a new explosive
of almost unbelievable destructive power.”
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Two weeks later, on April twenty-fifth, Stimson and Groves briefed Truman on the details of the Manhattan Project. They told
him scientists would soon complete “the most terrible weapon ever known in human history,” one of which “could destroy a whole
city.” They were confident the weapon would bring the bloody war to a rapid conclusion, thereby justifying the years of effort,
the vast expenditures, and the judgment of officials responsible for the project. A serious and thoughtful man, Stimson also
reflected on the bomb’s larger meaning in an accompanying memo. The world, “in its present state of moral advancement compared
with its technical development[,] would be eventually at the mercy of such a weapon,” he warned the new president, adding:
“Modern civilization might be completely destroyed.” Stimson asserted that “a certain moral responsibility” flowed from U.S.
leadership in this field that the nation could not shirk “without very serious responsibility for any disaster to civilization
which it would further.”
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To address this serious challenge, Stimson proposed the establishment of a committee to consider the proper use of the bomb
once it was finished and the postwar problems related to its development. Truman agreed, and the Interim Committee, as the
advisory group came to be known, was created on May 1, 1945.
*
Stimson sought to keep the Interim Committee small enough to conduct meaningful discussions but varied enough in its membership
to represent diverse viewpoints. More than a year after Bohr had urged policy makers to begin looking ahead, machinery was
finally established to consider the most momentous and dangerous development of the war. Stimson’s charge to the committee
asked for advice about
how
, but not
whether
, the bomb should be used against Japan. That the bomb would be used once it was ready seems to have been a foregone conclusion.
A Scientific Advisory Panel to the Interim Committee was also created, composed of Compton, Lawrence, Oppenheimer, and Fermi,
the first three chosen because they were directors of the Chicago, Berkeley, and Los Alamos laboratories; Fermi, because of
his unrivaled knowledge of nuclear physics. The Scientific Advisory Panel reflected policy makers’ desire for expert advice,
but it was also an attempt to preempt discontent among scientists if decisions were made about how to use the bomb without
consulting those who had made it.
Somewhat like Szilard, Oppenheimer, after much soul-searching, had concluded that the bomb he and others at Los Alamos were
making
had
to be used because that was the only way to awaken the world to the necessity of abolishing war altogether. No demonstration—even
if it was possible under wartime conditions, which he doubted—could take the place of actual combat use, with its horrible
and sobering results. Moreover, Oppenheimer thought it would be very difficult if not impossible to get political action on
international control
unless
the bomb’s immensely destructive power deeply penetrated the popular mind. “My own view,” he asserted later, “is that the
development of atomic weapons can make the problem more hopeful because it intensifies the urgency of our hopes—in frank words,
because we are scared.”
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He hoped that a military demonstration of the bomb would compel a general recognition that pre-atomic age calculations had
to give way to new realities.
Oppenheimer privately worried to Szilard, however, that Washington officials had inadequately pondered these sobering new
realities. Oppenheimer’s worry intensified Szilard’s own fears. Referring to the prospects of a “superbomb” infinitely more
powerful even than an atomic bomb, he asked Oppenheimer “what men like Stimson and Wallace would think if they were fully
advised of the turn which the technical development can be expected to take within a few years.”
Using the bomb did not necessarily mean using it on a civilian target. Szilard knew, however, that he faced an uphill battle
persuading Oppenheimer to oppose dropping the bomb on a Japanese city. “I expect that you who have been so strenuously working
at [Los Alamos] on getting these devices ready will naturally lean towards wanting that they should be used,” he told him.
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In this, Szilard was perceptive. Work on the atomic bomb had begun in the spring of 1939 out of fear that the Nazis were
building one of their own, but the surrender of Germany in the spring of 1945 brought the resignation of only
two
scientists at Los Alamos. If others thought of leaving—or debating use of the bomb—a meeting that Oppenheimer called a few
days after Germany’s surrender stopped them in their tracks. Oppenheimer told them they should finish their task and leave
the politics to policy makers in Washington. “He was very uncompromising and very sharp,” remembered one who attended the
meeting. “He indicated that he would not tolerate that kind of discussion and he implicitly invited those who felt that way
to get out.”
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No one else left.
The project had long ago assumed a momentum and a life of its own. It had become a monumental scientific and engineering endeavor,
involving prodigious effort and expense and labor. It was now a hurtling train moving forward—like the Pacific War itself—with
awesome, almost unstoppable force. Most scientists were too involved in their work and too committed to achieving their goal
to stop and reflect. “Most people just didn’t think too much about what would happen,” recalled a physicist on the Hill that
spring—“No, that was somebody else’s problem.”
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What had begun as a fearful race with Nazi Germany had become an end in itself. “I don’t think there was any time where we
worked harder at the speed-up than in the period after the German surrender and the actual combat use of the bomb,” Oppenheimer
recalled after the war.
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