By 1944 the Allies held the upper hand everywhere. The open questions were how to finish the war, and at what cost to whom.

Closing in on Germany

Western Allied armies invaded Sicily and then mainland Italy in 1943, and Mussolini fell from power that July, though fighting in Italy dragged on until 1945. The Soviets had long pressed for a second front in France. It came on 6 June 1944, when Allied troops landed in Normandy: about 156,000 American, British, Canadian and other troops came ashore or dropped from the air on the first day, after deception had persuaded the Germans that the main blow would fall elsewhere. After weeks of hard fighting the Allies broke out, Paris was liberated in August, and a last German offensive through the Ardennes in December, the Battle of the Bulge, failed. The Red Army pressed in from the east and reached Auschwitz in January 1945. Allied soldiers who entered Bergen-Belsen, Buchenwald and Dachau that spring found thousands of starving survivors and unburied dead. Leaders of Britain, the United States and the Soviet Union met at Yalta in February 1945 to plan the postwar world. With Soviet troops fighting in Berlin, Hitler killed himself on 30 April, and Germany surrendered unconditionally in early May 1945, signing on 7 and 8 May.

Bombing cities

Air power promised to win the war more cheaply. British Bomber Command turned to area bombing of German cities at night, joined by American daylight raids. In July 1943 raids on Hamburg created a firestorm that killed around 37,000 people. A commission of historians concluded in 2010 that the Dresden raids of February 1945 killed up to 25,000 people, far fewer than the hundreds of thousands once claimed. Defenders argued that bombing destroyed industry, pulled German fighters and guns away from the fronts and was for years the only way to strike Germany directly. Critics then and now, including the Anglican bishop George Bell, held that deliberately targeting civilians was wrong. Against Japan, US bombers switched to low-level night attacks with incendiaries. On the night of 9 to 10 March 1945 a fire raid on Tokyo killed around 100,000 people, a toll comparable to Hiroshima's.

The last months in the Pacific

In October 1944 the Battle of Leyte Gulf in the Philippines, often called the largest naval battle in history, broke the Japanese navy, and Japan began sending kamikaze pilots to crash their planes into ships. The battles for Iwo Jima and Okinawa in 1945 were among the bloodiest of the war; on Okinawa perhaps 100,000 civilians died. Soldiers and civilians alike had been taught that surrender was disgraceful, and on Saipan and Okinawa many civilians killed themselves or were pushed to it by Japanese troops. On 26 July the Allies issued the Potsdam Declaration, which demanded Japan's unconditional surrender and warned of total destruction otherwise. Japan's government did not accept.

Hiroshima, Nagasaki and the surrender

On 6 August 1945 an American bomber dropped an atomic bomb on Hiroshima, and on 9 August a second fell on Nagasaki. By the end of 1945 roughly 90,000 to 140,000 people had died in Hiroshima and 60,000 to 80,000 in Nagasaki, many from burns and radiation sickness, and the survivors, the hibakusha, bore the effects for life. Between the two bombs, on 8 August, the Soviet Union declared war on Japan and invaded Manchuria the next day. On 15 August Emperor Hirohito's recorded voice told the Japanese people the war was over, and the formal surrender came on 2 September.

The atomic debate

Was the bombing necessary or justified? The traditional view, set out by War Secretary Henry Stimson in 1947, holds that the bombs shortened the war and saved lives that an invasion would have cost; Japan's army still had millions of men and was preparing a last stand on the home islands, and each month of war meant more deaths across occupied Asia. Revisionist historians, notably Gar Alperovitz, argued that Japan was close to collapse and that the bombs were aimed partly at impressing the Soviet Union. Tsuyoshi Hasegawa contends that Soviet entry shocked Japan's leaders as much as the bombs, since it ended their hope that Moscow would broker a deal. Some scientists, in the Franck Report of June 1945, had urged a demonstration on an empty area first. Moral critics argue that killing tens of thousands of civilians cannot be justified by results; defenders reply that blockade, firebombing and invasion would also have killed civilians in vast numbers.

Worked example: a decision with incomplete information

Put yourself in Washington in July 1945. Intercepted cables show Japan's foreign minister seeking Soviet mediation, but on terms that keep the emperor and avoid occupation, and the army insists on fighting on. Okinawa has just cost over 12,000 American lives. You do not know when the Soviets will attack or how Japan will react. The options are invasion, continued blockade and bombing, softer terms that guarantee the emperor, a demonstration, or a city. For each, ask who would likely die and how many. Historians who weigh these choices differently are not careless; they disagree about what leaders knew, and about whether saving lives can justify targeting civilians.