Even as Bohr arrived in the United States for the purpose
of contributing to research on nuclear weapons, he expressed concerns
for the future of nuclear weapons. He sought a way to reach the
president to urge the necessity of early planning of postwar atomic
policy. Soon, however, he and his son Aage, who accompanied him
as an assistant and later became a theoretical physicist as well,
were on their way to Los Alamos. Bohr and Oppenheimer agreed that
his main responsibility should be to review all phases of the project
to ensure that nothing had been overlooked. In truth, as Bohr would later
tell a friend, the team did not need him to make the bomb. He did
serve another vital role, however. The scientists at Los Alamos inevitably
began to feel guilt, fear, and doubt about their work and the harrowing
consequences to which it could lead. Bohr felt these fears as deeply
as anyone, but he brought a sense of optimism to the project. He
showed not only that the bomb's construction was necessary to combat
Hitler, but that its power could create opportunities to establish
a stronger peace than had ever been possible.
Before long, the bomb was nearing completion, and Bohr
felt that it was time to make further attempts to get his warnings
to the highest powers: Roosevelt and Churchill. He was less concerned about
Germans than the Russians, and whether and how much they should
be told. If the Americans and British were open, then international
policy regulating nuclear development could be enacted. But if
they hid information from the Russians, the Russians were likely
to develop the knowledge themselves and then be less likely to cooperate.
After many obstacles, Bohr succeeded in obtaining a meeting with
Churchill, but the meeting proved unproductive, largely because
the two diametrically opposed personalities could not understand
each other. Churchill, who had moved many with his commanding voice,
had little interest in Bohr's mild whisper.
On the other hand, Roosevelt was much more understanding.
He agreed generally with Bohr's prescriptions and saw how critical
his steps were in maintaining atomic energy for good purposes.
Further, he agreed to attempt to change Churchill's mind at their
next scheduled meeting in Quebec. Instead, Roosevelt left the meeting much
less confident in Bohr's proposal. Although no record of their conversation
exists, evidence indicates that Churchill may have attacked Bohr
personally, questioning his credibility and insinuating his loyalty
to the Russians. Churchill's charges, of course, were unfounded
and could easily have been verified. Instead, Churchill relied
on stubborn instinct, and the force of his personality won Roosevelt
to his side.
Soon after, Truman replaced Roosevelt, and in July of
1945, the bomb was successfully tested. Ironically, Stalin showed
little interest when Truman hinted at the completion of "a new
weapon of unusual destructive force." The Russian premier merely
expressed the hope that it would prove useful against the Japanese.
Bohr had fought a brave battle, and many scientists and
statesman joined his efforts. Bohr continued campaigning even after
the war, with the help of his former Copenhagen fellow Hendrik
Kramers, then chairman of a United Nations committee on nuclear
policy. But the arms race would develop exactly as Bohr had feared.
In the meantime, as 1945 saw the emancipation of Denmark, Bohr concentrated
on getting back home as soon as possible.