This short but quietly devastating book traces the descent of the United States government and military into barbarism during the final months of the Pacific War. Between March and August 1945, in the ‘rain of ruin’ of the title, US aircraft killed over 300,000 Japanese civilians in a campaign of incendiary bombing and two nuclear strikes, brushing aside the attempts made by the high-minded diplomats who had drawn up the Hague Conventions and the Hague Rules of Air Warfare to outlaw aerial attacks on civilians and civilian property. During the firebombing of Tokyo on the night of 9–10 March 1945, around 40 per cent of the Japanese capital was incinerated. Women in flight with babies strapped to their backs failed to notice in time that the infants were burning to death; people seeking shelter in buildings were ‘steamed, braised, asphyxiated, and finally reduced to a thick layer of ash’. This exercise in ‘conventional’ bombing eased the way to approval of the dropping on 6 August of the first atomic bomb on the city of Hiroshima. An eyewitness left an account of a trail of victims making for the hills: ‘parts of their bodies were missing, flesh and skin hanging from their bones, some with eyeballs hanging in their hands, and some with their stomachs burst open, their insides hanging out’.

What induced the generally civilised US leadership to give the green light to these horrors? Their chief motive was an understandable one – to end the war rapidly and avoid the loss of perhaps a quarter of a million American lives in an attempt to storm ashore in Japan. But Richard Overy notes that a number of additional factors were at work. There was the desire to avenge the hideous war crimes committed by the Japanese forces, in particular their butchery of American nationals at Pearl Harbor and during the Bataan Death March in the Philippines. There was the sheer hatred felt by many Americans for an enemy they regarded as less than human – people have occasionally wondered whether, had Germany rather than Japan been the last Axis power left standing in August 1945, the atomic bomb would have been dropped on a German city. Also, while there was intelligence that Japan was seeking a settlement through the offices of the Soviet Union, other reports indicated that the Japanese were reluctant to give in.

Overy shows that US opinion was by no means monolithic. On the side of the angels, for instance, was General Dwight Eisenhower, who considered the use of the atomic bomb ‘unnecessary and unlawful’. At the opposite extreme was General Curtis LeMay, the military man who was placed in charge of both the firebombing campaign and the two subsequent nuclear attacks. LeMay appears to have felt no qualms whatever about his role in these operations. Of the Tokyo firebombing he wrote, ‘We knew we were going to kill a lot of women and kids when we bombed that town. Had to be done.’ The scientists at work on the Manhattan Project, the programme for developing an atomic bomb, were divided between a team at Los Alamos, New Mexico, which was broadly in favour of putting the weapon into immediate military use, and another in Chicago, most of whose members felt that a demonstration bomb should be exploded first over the sea or a desert to give Japan a chance to surrender without loss of life. In Washington, DC, the decision-makers shifted uneasily between moral reservations about dropping the bomb and a feeling that this was ‘our least abhorrent choice’.

The case for bombing was powerfully reinforced by US military analysts, who claimed that Japanese cities were legitimate targets because much of Japan’s war production was carried out via an urban network of small craft shops, and by doctors explaining that radiation sickness was ‘a very pleasant way to die’. In a radio broadcast on 10 August, the US president, Harry Truman, informed the American public that the Hiroshima bomb had been dropped on ‘purely a military base’ because ‘we did not wish to destroy the lives of women and children and innocent civilians’. Did Truman really not appreciate what sort of place Hiroshima was? Whatever the answer, he seems by the end of the year to have satisfied himself that saving a quarter of a million young American lives ‘was worth a couple of Japanese cities’.

Overy has written extensively about many different aspects of the Second World War. In this book, he adds new perspectives to a subject that has often been approached from a narrowly American angle. Thus, he draws attention to the role of the British, who had pioneered the tactics of aerial warfare as early as 1942 through the creation of Bomber Command and the devastation of German cities. US observers at that stage were highly critical of the ‘terror bombing’ employed by the RAF. By the time the Americans had embarked on their own incendiary onslaught, however, US and British bombing experts were working closely together. The British were anxious to be ‘in at the kill’ in Japan in order to shore up their waning prestige in East Asia. A contingent of British scientists was present at Los Alamos to work on the atomic bomb project from 1944.

More important is the picture Overy has been able to draw from his study of Japanese sources. The apparent reluctance of Japan to surrender, which perplexed the Americans, stemmed in part from the fact that the Japanese had no concept of surrendering. Their country had never in its history been faced with the need to capitulate, and its spokesmen could only express themselves in terms of ‘terminating the war’. This didn’t mean that the Japanese didn’t want peace. Emperor Hirohito himself privately voiced his desire for a settlement in response to the March 1945 firebombing of Tokyo. In the following months, unknown to the US government, a peace faction grew up in Japan. By 9 August, it had man­oeuvred Japan’s Supreme War Council into debating acceptance of the Allied surrender terms. The council’s discussions had already begun when the second atomic bomb was dropped on Nagasaki. Americans were left with the impression that the nuclear bombings had been decisive in ending the war by breaking the enemy’s will to resist, but it seems possible that the war would still have been ‘terminated’ had the strikes on Hiroshima and Nagasaki not taken place.

Overy shows plainly that the nuclear bombings were only one of a number of actions that sapped Japan’s resistance in the final months of the war. Japan’s leaders were demoralised by successive military defeats, which culminated in the fall of Okinawa on 22 June 1945. The continued firebombing wrecked cities all over the country and precipitated economic collapse through disruption of industrial output, dispersal of the surviving urban populace and destruction of transport links. A naval blockade imposed by the United States resulted in a decline in imports and brought a danger of famine. This in turn raised the prospect of social upheaval, which terrified the deeply conservative Japanese ruling elite. On 9 August, Soviet forces marched into Japanese-held Manchuria in support of the Western powers under an agreement reached at Yalta six months before. Intent on rebuilding Russia’s strategic position in the Far East, Stalin had his sights set on taking Hokkaido, the northernmost of the main Japanese islands, and turning it into a Soviet-occupied zone. To Japan’s leaders, the advent of communism in their own country seemed a real possibility. Like their counterparts in Germany on the eve of the Nazi collapse, they were desperate to do whatever it took to ensure that the Americans reached them before the Soviets did.

Following Japan’s surrender and occupation by US forces, propagandists in Washington sought to sanitise depictions of the aerial bombing campaign. The two nuclear attacks were presented as both necessary and legitimate. In occupied Japan, strict censorship was imposed to prevent the publication of accounts of the bombings in the interests of ‘public tranquillity’ (at the time, the United States was anxious to co-opt Japan as an ally in the new Cold War). After the end of the occupation in 1952, the Japanese government continued to play down the horrors of the US bombings in the interest of maintaining American economic support and protection from the menace of the Soviet Union and newly communist China. 

The US military emerged from 1945 convinced that wars could be won through the use of saturation bombing to shatter the morale of the enemy population – a conviction that was shown to be deluded in both Korea and Vietnam. And far from being condemned as intolerable from an ethical standpoint, the aerial bombardment of cities (including with nuclear weapons) continued to be included in US and British military planning throughout the Cold War. While there has apparently been a return in some military circles to the pre-Second World War aspiration to ban waging war on civilians, there has been precious little sign of restraint on the battle­field in recent years. Overy’s book is a sombre reminder that the border between civilisation and savagery is wafer-thin.