1. The Atomic Bomb End of the War

2. FDR to Truman Roosevelt did not live to see the final battles of the Pacific war (died of a stroke o April 12, 1945) Harry S. Truman became the nation’s president while America grieved for its beloved FDR The war in Europe was winding down, but the ferocious battles raging in the Pacific continued The Battle of Iwo Jima and the Battle of Okinawa left the U.S. hesitant; these battles were a chilling foretaste of what American troops might face in the final invasion of Japan – Winston Churchill predicted that over a million American lives would be lost

3. The Manhattan Project Upon becoming President, Truman was introduced to the Manhattan Project Work on the atomic bomb had begun in 1942 – Scientists under Enrico Fermi successfully achieved a controlled nuclear reaction General Leslie Groves (the organizer of the Manhattan Project) had two gigantic atomic reactors built to produce uranium 235 and plutonium Meanwhile, scientists under J. Robert Oppenheimer worked in a secret lab in New Mexico building the actual bomb – American, British, and refugee European scientists worked together

5. Testing the Bomb Eventually, the scientists in New Mexico had to test the bomb – Some feared that the bomb wouldn’t work or wouldn’t very powerful – Others predicted that it would end the world On the night of July 16, 1945 the first atomic bomb was detonated in an empty expanse of desert – The blinding flash was visible 180 miles away The scientists and military were shocked at the power that this new weapon had achieved

6. Debating the Atomic Bomb Many of the scientists who had worked on the bomb felt that the atomic bomb might be too devastating – Many of the scientists felt that it was immoral to drop the atomic bomb on Japan without warning – Others believed that a demonstration of the bomb’s capabilities be shown to Japanese leaders These objections were discussed at the newly formed Interim Committee where J. Robert Oppenheimer presented the problems – 1) Nothing less than actually dropping a bomb on a city would convince the Japanese to surrender – 2) What if the test shown to the Japanese was a dud? – 3) The Japanese might have a chance to shoot down the plane carrying the bomb if they knew it was coming – 4) The Japanese might move American POWs into the testing ground if they are forewarned

7. Reasons for Using the Bomb The Interim Committee recommended that the bomb be used against military targets in Japan without warning Many scientists agreed with this decision as the heavy causality figures on Iwo Jima and Okinawa sank in – Saving American lives was the main reason cited for using the bomb Two other concepts for using the bomb became major considerations – The Manhattan Project was expensive; not dropping the bomb would be a gigantic waste of money = about 500 million dollars – The Allies (and American) distrust of the Soviet Union – If the U.S. dropped the atomic bomb, they would scare the Soviets and the U.S. would have more leverage in shaping the postwar world

8. Truman’s Decision Truman did not hesitate to use the bomb once he learned of its successful test run On July 25 th, Truman ordered the military to design plans to drop the only two existing atomic bombs on Japan The U.S. warned Japan that it faced “prompt ad utter destruction” unless they surrendered (Japan refused the Potsdam Declaration) Truman gave the military full support to drop the atomic bombs on Japanese cities

10. Hiroshima On August 6 th, a B-29 bomber (the Enola Gay) released an atomic bomb (codenamed Little Boy) over Hiroshima at 8:15 AM Hiroshima was an important Japanese military center, but consisted mostly of civilians 43 seconds later, almost every building in the city collapsed to dust = Hiroshima was gone – Directly killed an estimated 80,000 people – Over 60,000 more died from the radiation within the year – The worse of the two cities that were bombed Japan and its leaders still refused to surrender

12. Nagasaki Three days later the second and final bomb (codenamed Fat Man) was released over the city of Nagasaki Half of the city was completely destroyed and an estimated 40,000 civilians were killed instantly By the end of the year, an estimated 200,000 people had died from the bomb or radiation poisoning caused by the atomic blasts

14. Japan Surrenders Emperor Hirohito was horrified by the death and destruction – “I cannot bear to see my innocent people suffer any longer” – Emperor Hirohito The Emperor ordered Japan’s leaders to draw up treaty papers that would end the war – Six days after the second bomb Japan declared their desire to surrender On September 2, 1945 Japan formally surrendered to the United States – The surrender occurred on the U.S. battleships Missouri in Tokyo Bay World War II was over = the Allies had won