| caption = Remember Dec. 7th! 1942 Office of War Information poster promoting a sense of common purpose during World War II.
'''World War II ''' formally began in September 1939, with Germany's invasion of Poland, although military aggression had taken place between various countries of the world for several years before that date. Germany had been conquering its central European neighbors since the mid 1930s, while Italy had conquered vast amount of territory in North Africa. Japan had also used military force to expand into Asia beginning in the early 1930s. There are numerous reasons for why World War II began. Among the more important ones ranks a desire for Germany to reclaim land seized from it following the German defeat in World War I. Germany, Italy, and Japan also helped their people cope with the Great Depression by building up their respective militaries. Jobs opened in defense plants, as these nations expanded their militaries. Other men found jobs in the armed forces of these nations. As these nations became militarily stronger, nationalism and a general desire to be the most powerful country on the earth prompted them to expand. At the beginning of World War II, the United States was not an active participant. At the same time, Americans were preparing for the possibility of war. The U.S. government actively assisted Great Britain in Europe against Germany by lending or leasing the British military equipment and trading the British fifty U.S. destroyers for approximately one dozen British military bases around the world. Because countries were involved in a major struggle on the continent of Europe, Japan was able to expand its control in Asia and in the rest of the Pacific. The Japanese were concerned about the United States' strength and the potential for American involvement in the war. As a result, Japanese military leaders, led by Admiral Isoroku Yamamoto, planned a preemptive attack on the United States naval base at Pearl Harbor, the home port for the U.S. Pacific Fleet. They hoped to significantly weaken the U.S. Pacific Fleet and prolong American entry into the war. The Japanese attack took place on December 7, 1941. The Americans were totally surprised by the attack, suffering high casualties. By the time that the attack was over, 2,390 Americans had lost their lives. Three American battleships, the ''USS Arizona '', the ''USS Utah '', and the ''USS Oklahoma '', were totally destroyed. The other American ships also saw heavy damage but were later repaired and returned to duty. The Japanese also destroyed many American aircraft located at nearby airfields. Three Ohioans won Congressional Medals of Honor for their heroism during the attack on Pearl Harbor, including Rear Admiral Isaac Campbell Kidd of Cleveland, Machinist's Mate First Class Robert R. Scott of Massillon, and Seaman First Class James Richard Ward of Springfield. All three men died during the attack, sacrificing their lives for others. Numerous other Ohioans also died at Pearl Harbor. The following day, President Franklin Delano Roosevelt asked Congress for and received a declaration of war against Japan. Roosevelt referred to the attack on Pearl Harbor as "a date that will live in infamy. " The words "Remember Pearl Harbor " became a rallying cry for Americans during the war. On December 11, 1941, Germany, believing that the Americans could not fight a war in Europe while fighting a war in Asia, declared war upon the United States. While Japan had caused the United States to become involved in World War II, President Roosevelt focused the United States' military efforts on Germany and Italy first. Germany had conquered most of Europe by late 1941, leaving only the Soviet Union, which was in danger of collapse, and Great Britain to stand against the Germans. Roosevelt hoped to save Great Britain, a long-time ally of the United States, from German defeat. In the Pacific, against Japan, Roosevelt wanted to stop Japanese expansion, but did not seek an immediate defeat of this enemy. He believed that the mainland United States was in no immediate danger of Japanese invasion, and thus the United States should help its European allies. In 1942, the Allied Forces succeeded in freeing North Africa from German and Italian forces. In 1943, the allies secured Sicily and also conquered Italy. In June 1944, the Allied Forces invaded France. The Soviets had asked for this invasion to occur in 1942, because they wanted to force the Germans to fight a two-front war-one in Eastern Europe against the Soviets and one in Western Europe against the Americans and the British. The United States' failure to invade France in a more timely manner increased tensions between the two countries, helping to lead to the Cold War following World War II. The Soviets had already made tremendous inroads by 1944 against the Germans in Eastern Europe, reversing their fortunes from late 1941 and 1942. With the Germans now having to fight a two-front war, Germany fell relatively quickly to the allies. Germany formally surrendered on May 7, 1945. Against Japan, the United States adopted what became known as an island-hopping campaign across the Pacific Ocean. Rather than driving the Japanese military from every island that it occupied, United States soldiers usually attacked those islands that would provide the Americans with good naval bases and airstrips. The Japanese soldiers on the islands that the Americans did not attack became isolated and no longer served as a major threat to American troops. By early in 1945, this strategy had led the United States to Japan's doorstep. United States military experts guessed that an invasion of Japan would result in more than one million dead Americans. To help reduce American casualties, President Harry S. Truman authorized the use of atomic bombs against Japan. American scientists had been trying to develop an atomic bomb since early in World War II. They believed that such a bomb would be capable of destroying entire cities. In the United States, physicist J. Robert Oppenheimer and General Leslie R. Groves spearheaded the drive to create this weapon. Groves formally named the attempt the "Manhattan Engineering District, " since his headquarters was located in Manhattan, New York, although the effort became better known as the "Manhattan Project. " Oppenheimer and Groves concentrated research efforts in Hanford, Washington; Los Alamos, New Mexico; and Oak Ridge, Tennessee; although numerous other centers, including Battelle in Columbus, Ohio, participated in the development of the bomb. Eventually 130,000 people participated in the Manhattan Project. By July 1945, scientists had developed three atomic bombs. After a successful test of the first bomb near Alamogordo, New Mexico on July 16, 1945, President Truman authorized the United States military to utilize another atomic bomb against Japan. On August 6, 1945, the crew of the ''Enola Gay '', which was piloted by Ohioan Paul Tibbets, dropped an atomic bomb on Hiroshima, Japan. Approximately 200,000 people died. This atomic bomb, nicknamed Little Boy, along with a second atomic bomb, dropped on Nagasaki, Japan, on August 9, 1945, prompted the Japanese government to surrender. Ohioans played a critical role in helping the United States attain victory in World War II. Approximately 839,000 Ohioans, roughly twelve percent of the state's entire population in 1940, served in the armed forces during the conflict. Of these men and women, twenty-three thousand of them died or were missing in action by the war's conclusion. Ohio civilians also actively participated in the war effort, joining in scrap drives and growing victory gardens. Tens of thousands of people also flocked to Ohio, seeking jobs in defense industries. Many of these workers came from Appalachia. Women also found ample opportunities for employment in defense plants and in the armed services. Companies like Willys-Overland Company, which produced jeeps for the military, and the Goodyear Aircraft Corporation, which produced airplanes, both prospered during the war. Thanks to the efforts of Ohioans and other Americans, the United States emerged from World War II triumphant.[[Category:History Events]] [[Category:Great Depression and World War II]]