Prior to the Second World War it had been claimed that air power acting on its own might be a viable alternative to large land armies. This was reflected in the use of the adjective ‘strategic’ as applied to ‘bombardment’, suggesting that air raids could be launched over the heads of land forces and thereby send a population into panic and despair, obliging an enemy government to beg for mercy. The experience of the Second World War qualified this optimism. Strategic bombardment did not produce sudden collapses in morale but became another instrument of attrition, at first gradually but then at an increasing pace, eating away at the war-making potential of Germany and Japan. In securing the final victories command of the air had been vital, but it had not been won easily and was not sufficient in itself. The European war was ended by the Allies physically fighting their way into Germany.
The advent of atomic weapons revived thoughts of a decisive strategic instrument. During the late 1930s news came through of a series of advances in nuclear physics that pointed to techniques for splitting the atom and then creating a chain reaction that would unleash vast amounts of energy. War soon provided the incentive to see how far the theory could be taken. After Pearl Harbor, the British effort to design an atomic bomb, which was quite advanced, was merged with the far better resourced American Manhattan Project. Here an international group of scientists, many of them refugees from Nazi Europe, were determined to construct this terrible new weapon before Hitler did. Others hoped that they would perform a service to humanity by demonstrating that it was a practical impossibility. In the event, the weapon was not ready by the time of Germany’s defeat in May 1945, and fortunately Hitler’s own programme had fizzled out before it was close to success.
The war with Japan was not yet over. Victory was almost certain, but Truman was concerned about the heavy loss of life that would result if an invasion had to be mounted, and was happy to explore all means to get a Japanese surrender as quickly as possible. After the first successful test of an atomic weapon in New Mexico in July 1945, news of which came through as the ‘Big Three’ assembled at Potsdam, Truman decided to use the couple of weapons available to shock the Japanese government into surrender by demonstrating this terrible power that could now be unleashed. Given the expense of their development he was not inclined to hold the weapons in reserve, and neither he nor his advisers were impressed by anguished pleas from many of the scientists involved that they should either desist altogether or rely on a demonstration shot away from a civilian population. For years both sides had been engaged in air raids of ever-growing intensity, culminating in the fire-bombing of Tokyo the previous March. At this stage of the war the moral argument against attacks on cities had long been lost, provided some military rationale could also be found. The first of the only two nuclear weapons ever to be dropped in anger detonated over the Japanese city of Hiroshima, which Truman described as an important military target, on the morning of 6 August 1945. It led to 200,000 deaths and injuries. The second bomb hit Nagasaki three days later. After another five days Japan surrendered.
The conditions flattered the new weapon. Japan was close to defeat and lacked any means of response. The Soviet Union was also entering the Pacific war. Yet whether or not Japan would have surrendered anyway – as much evidence now suggests – it would also seem that the shock effect of the bombs tilted the internal debate in Japan towards accepting defeat earlier rather than later. Hiroshima and Nagasaki have been described as the first shots in the Cold War, because they provided an opportunity to demonstrate American strength in a grimly convincing manner to Stalin during a critical stage of the bargaining over the shape of the post-war world. While this may have been a presumed side-benefit, the record shows that Truman’s main concern was with getting the Pacific war over as soon as possible.
The impact of these two attacks on the post-war world was immediate and profound. First they made it possible to imagine circumstances in which Russia could be defeated without having to brave its distances and climate. Second, the association of the new weapons with victory meant that they immediately acquired an aura of decisiveness, whether warranted or not. Third, they confirmed a trend towards progressive barbarism in warfare. Once a major war began there could be no presumption of innocence and no expectation of pity. While at first the stockpile of atomic weapons was very small (indeed, barely more than component parts in the years just after the war), and so appeared as providing merely a more efficient way to mount a conventional air raid, the fact that mass destruction could be instantaneous and include the insidious effects of radiation inevitably led to these weapons soon dominating all speculation on future warfare.
In the first couple of years of peace the Americans took steps to guard their atomic secrets, even from their British allies who had played a significant early role in the weapons development, but they did little to produce many new weapons. That effort began in earnest in 1947, after it had become clear that any hopes for placing this new technology under international control were doomed to disappointment. Proposals had been put forward by the United States, under the name of its chief delegate, Bernard Baruch, to a United Nations committee for the international control of atomic energy. In the circumstances this was a generous gesture, but it could never be convincing to Moscow, which saw in the scheme an early obstruction to its own nuclear programme with a political option whereby the Americans might avoid at a late stage any obligations to relinquish their own arsenal.
The mushroom cloud from the “First Lightning” test (1949).
It had been assumed by the Americans that the Russians were far behind in nuclear technology. However, by dint of their own hard work, well-placed spies (notably Klaus Fuchs, who had been a British participant in the Manhattan Project) and a full published description by American scientists of their methodology, the Russians made rapid progress. In August 1949 they tested their own nuclear device. As the test came at a time when East-West tensions were growing daily, the effect on the Americans was electrifying. They could no longer assume a nuclear monopoly: they were now engaged in an arms race. The response was not only to step up production of fission (atomic) weapons, but also to press ahead with the next stage of weapons development – the fusion (or thermonuclear or hydrogen) weapon, which promised almost unlimited destructive capacity. Leading American scientists were bitterly opposed to creating ‘city-busting’ weapons with an explosive yield equivalent to millions of tons (megatons) of TNT, but Truman felt that he had no choice. He dared not let the Russians build such a bomb first.
The president did accept, at the same time, that the Soviet breakthrough required a reappraisal of the strategic role of nuclear weapons. This took the form of a major study, led by the State Department, which considered this new development in the light of the deteriorating international political situation. The other major communist advance in 1949 had been the defeat of the nationalists in the Chinese Civil War. There was now a Sino-Soviet bloc, spreading right through the Eurasian heartland and capable of pushing out against all areas along its periphery. The resulting document for the National Security Council- known as NSC-68 – was designed to bring home to the Washington bureaucracy just how dangerous the situation had become. It warned that without determined action, democracies might succumb to a communist drive for world domination. So long as the United States enjoyed a nuclear monopoly it could be argued that this would serve as a powerful disincentive to Moscow if there was any thought of aggressive action. But if Moscow could retaliate in kind, Western plans to initiate nuclear war would appear reckless. It was therefore unwise to rely on this threat for the indefinite future if it risked bringing a terrible retribution on the United States. The conclusion of NSC-68 was therefore that the remaining years of nuclear superiority should be used to build up conventional forces in Europe capable of coping on their own with a Soviet assault.