Transcript Why Truman Used the Bomb

Atomic Bombs and World War II
Topic: From Isolation to
World War (1930-1945)
The isolationist approach to foreign policy meant
U.S. leadership in world affairs diminished after
World War I. Overseas, certain nations saw the
growth of tyrannical governments that reasserted
their power through aggression and created
conditions leading to the Second World War. After
Pearl Harbor, the United States entered World
War II, which changed the country’s focus from
isolationism to international
involvement.
Content Statement:
Use of atomic weapons changed the nature
of war, altered the balance of power and
began the nuclear age.
Expectations for Learning:
Summarize how atomic weapons have
changed the nature of war, altered the
balance of power and started the nuclear
age.
The Manhattan Project
• Early in 1939, the world’s scientific
community discovered that German
physicists had learned the secrets of
splitting a uranium atom
• Fears soon spread over the possibility of
Nazi scientists utilizing that energy to
produce a bomb capable of unspeakable
destruction
The Manhattan Project
• Code name for the American effort to
design and build an atomic bomb
• The main assembly plant was built at Los
Alamos, New Mexico
The only color photo of
the first atomic bomb
explosion
The Manhattan Project
• Robert Oppenheimer was
put in charge at Los Alamos
• Nearly $2 billion was spent
on research and
development of the atomic
bomb
• The Manhattan Project
employed over 120,000
Americans
The Manhattan Project
• Secrecy was paramount
• The project had to be kept secret from the
Germans and the Japanese
• Roosevelt and Churchill agreed that the
Stalin wouldn’t be told about the project
• Only a small group of scientists and
officials knew about the atomic bomb’s
development
The Manhattan Project
• Vice-President Truman never heard of the
Manhattan Project until he became
President
• July 16, 1945 at 5:30A.M.
–Tested the bomb
–Alamogordo, New Mexico
–First “mushroom” cloud
• Germany and Italy already surrendered
Japan Refused to Give Up
• American soldiers and civilians were
weary from four years of war
• The Japanese military was refusing to
give up their fight
• American forces were intensely firebombing Japanese cities
• Japan had an army of 2 million strong
stationed in the home islands guarding
against invasion
Japan Refused to Give Up
• Warned Japan
–They still didn’t give up
• The decision: Should we drop bomb?
–If yes--thousands of innocent Japanese
people would be killed
–If no--thousands of Americans would
be killed
The Decision to Drop the Bomb
• For Truman, the choice to use the bomb
was the most difficult decision of his life
• First, an Allied demand for an immediate
unconditional surrender was made to the
leadership in Japan
• The demand stated that refusal would
result in total destruction, but no mention
of any new weapons of mass destruction
was made
Hiroshima
• The Japanese
military command
rejected the request
for unconditional
surrender
• On August 6, 1945, a plane called the
Enola Gay dropped an atomic bomb on
the city of Hiroshima
Hiroshima
• Instantly, 70,000
Japanese citizens
were vaporized
• In the months and
years that followed,
an additional 100,000
perished from burns
and radiation sickness
Nagasaki
• On August 9, a second
atomic bomb was
dropped on Nagasaki
• 80,000 Japanese
people perished
• On August 14, 1945, the Japanese
surrendered
Why Truman Used the Bomb
• Truman rejected using a demonstration of
the atomic bomb to show the Japanese
leadership that we had it
• He knew there was no guarantee the
Japanese would surrender if the test
succeeded
• He felt that a failed demonstration would
be worse than none at all
Why Truman Used the Bomb
• A Normandy-type invasion would have
cost an estimated million casualties
• Truman believed that the bombs saved
Japanese lives as well
• Over 3,500 Japanese kamikaze raids had
already wrought great destruction and
loss of American lives
Results of Dropping the Bombs
• The dropping of the atomic bombs on
Japan hastened the end of World War II
and is considered the beginning of the
nuclear age
• The use of these bombs introduced a new
type of weapon capable of mass
destruction
Only Superpower
• For 4 years after end
of WWII the U.S. is
only superpower
because we have the
atomic bomb
• This deterred the
Soviet Union from
expanding their
influence over other
countries
Postwar – United States
• Lost thousands of people during the war
• Country is stronger than ever after the war
• Capitalism
– Economic system based on a free market,
open competition, profit motive and private
ownership of the means of production
• Believed the rest of the world should model us
• Want free elections, free trade, and business
expansion all around the world
Postwar – United States
• The old world order is gone
• The U.S. could no longer be isolated
• The U.S. now relied on world trade to
prosper
Postwar – Soviet Union
•
•
•
•
Lost over 7 million people during the war
Torn apart after the war
Wanted to build a strong country
Communism
– A theory or system of social organization
based on the holding of all property in
common, actual ownership being ascribed
to the community as a whole or to the state
• Believed the rest of the world should be
communist
Beginning of the Cold War
• Cold War
–War with no fighting
–Instead of fighting, use military threats,
espionage, propaganda, and politics
• Nuclear weapons developed
• The period right after World War II will
begin 50 years of Cold War between the
U.S. and the Soviet Union
Beginning of the Cold War
• The U.S. and Great Britain were allies with
the Soviet Union for one reason--to beat
Adolf Hitler
– They did not trust Stalin
Did not tell him about the atomic bomb
• Stalin expected entire world to become
communist
• U.S. and Soviet Union had very different
views of the future
Soviet Union Tests Atomic Bomb
• 1949: Soviet Union tests and explodes
atomic bomb
• This makes Soviet Union the 2nd
superpower
Arms Race
• Arms race between U.S. and Soviet
Union
–Occurred throughout Cold War
–Guarantee security
–The two sides competed with each
other to make the most and best
weapons for the next 50 years