Under the guidance of President Roosevelt, a top-secret joint effort between America and the United Kingdom was begun to build an atomic bomb that could be used against Germany. Slowly, the United States recaptured many of the small islands that had been invaded by Japan, including Guadalcanal, Bougainville, Tarawa, Saipan, Iwo Jima and Okinawa. In accordance with an agreement forged between President Roosevelt and British Prime Minister Winston Churchill, military strategists and politicians poured the majority of America's resources into the European theatre, and before the United States could fully mobilise, most of South-East Asia, including the Philippines, had fallen to Japan. America's determination to remain isolated changed abruptly following Japan's surprise attack on Pearl Harbor on 7 December, 1941. Tensions still remained high in Asia, though, and increased even further in 1939 when Germany ignited World War II with an invasion of Poland. The United States placed an embargo on materials, including oil, exported to Japan in the hope of curbing Japanese expansionism. Japan had expansionist aims in Eastern Asia and the Western Pacific, especially in Indochina.
The war in Asia had its roots in the early 1930s. However, because the alternatives were never fully explored, one can only speculate about whether or not Truman's decision to drop the bomb actually saved lives and if the decision was a morally correct one. With the fall of Nazi Germany, however, the target was shifted to Japan without even a break in stride. The initial target was Germany, who, it was thought, were on the brink of producing their own atomic bomb. For instance David H Frisch, a scientist working on the Manhattan Project, noted: 'It was very important to prove the bomb a successful weapon, thus justifying its great cost.' Also, it could be considered that the sheer momentum of the project carried it through to completion. The decision to drop the bomb was made because of many domestic and international pressures and concerns.
Today, 50 years after the two bombings, and with the advantage of historical hindsight and new evidence, a third view has been added. In the 1960s a second view developed that claimed the dropping of the bomb was a diplomatic manoeuvre aimed at gaining the upper hand in relations with the USSR. The traditional belief that dominated the 1950s and '60s - put forth by President Harry Truman and Secretary of War Henry Stimson - was that the dropping of the atomic bombs was a solely military action that saved as many as a million lives from the upcoming invasion of Kyushu 2. Many factors contributed to the final decision to use the bomb. The bomb dropped on Hiroshima, which was quickly followed by a second bomb dropped on Nagasaki three days later, forced Japan into a quick surrender.
Over 240,000 Japanese civilians died - Pearl Harbor's devastation had been recreated 100 times over. The attack on Pearl Harbor four years earlier was one of the justifications President Truman gave for his decision to use the nuclear weapon. Four years later, on 6 August, 1945, at precisely 8.15am, the first atomic bomb to be used in anger 1, exploded over the city of Hiroshima. Because the Americans were taken by surprise, 19 ships were sunk and about 2400 American soldiers and sailors were killed. On 7 December, 1941, Japan attacked the American fleet at Pearl Harbor, Hawaii.