‘The attack would signal the beginning of the end of Japan’s empire in Asia and the Pacific’

Satona Suzuki, Lecturer in Japanese and Modern Japanese History at SOAS, University of London

On 7 December 1941 Japan launched a surprise attack on the naval base of Pearl Harbor in Honolulu, Hawaii, triggering war with the US. Japan had, until that point, avoided conflict with the US, but lacked a united strategy due to a severe lack of communication between its government, army and navy, which each had different agendas. The Japanese government strove to avoid war through diplomatic channels, while the army was keen to fight the Soviet Union, its hypothetical enemy. The navy, which had been criticised as ‘useless’ since the London Naval Treaty of 1930 – an agreement between the United Kingdom, the US, Japan, France and Italy to regulate naval warfare and limit shipbuilding – advocated war with the US in order to restore its raison d’être. This proved the outcome, despite Japan being far inferior to the US in terms of national strength, natural resources and production capacity. 

Japan’s attack on Pearl Harbor changed the other Axis powers’ discourse in Europe. The Tripartite Pact, signed between Japan, Germany and Italy in September 1940, was a military alliance promising mutual political, economic and military assistance should any of them be attacked. Ironically, Tokyo had hoped to negotiate with the US through this alliance, while keeping it in check. The news of Pearl Harbor delighted Hitler, who saw the initial success of Japan’s surprise attack as an opportunity. Even though Japan had initiated the attack, he declared war on the US a few days later on 11 December. Italy followed suit on the same day. The impact was to drag the US, a major economic power, into the war as an adversary. This overestimation of the wisdom of Japan’s strategies in the Pacific ultimately helped none of the Axis powers. 

On Japan’s part, the attack on Pearl Harbor was a great gamble. A combination of a lack of communication on many fronts, the overwhelming differences in economic power between Japan and the US and miscalculations based on short-sighted strategies contributed to Japan’s and the other Axis powers’ defeat in the Second World War. It would also signal the beginning of the end of Japan’s empire in Asia and the Pacific.

‘Without a war in Asia, any American entry into the European war would have been more difficult’

Rana Mitter, Professor of the History and Politics of China at Oxford University and author of China’s War with Japan, 1937-1945: The Struggle for Survival (Allen Lane, 2013)

Before you consider whether Pearl Harbor was a turning point, you have to bear in mind that the attack on Hawaii was not inevitable. Consider the experience of the country that was fighting invasion two years before Hitler’s attack on Poland: China. 

For much of the early 20th century, tensions between China and Japan had been rising, and on 7 July 1937 war broke out. A year later, by mid-1938, things looked very bad for China. Much of its cultural heartland had fallen to the Japanese, including the great cities of Nanjing, Beijing and Shanghai. China had no formal allies and unofficial assistance from the Soviet Union, Britain and the US was only a stopgap measure. Many observers thought that the only logical outcome was for the Chinese Nationalist leader Chiang Kai-shek to do a deal with Japan.

Chiang thought differently, as did his uneasy allies, the Chinese Communists. Both decided, against the odds, to resist the invaders and hope that they could bring allies into the battle. It took several more years. Not until December 1941, and Pearl Harbor, did the US and the British Empire join China in the war against Japan.

But consider the result if Chiang had done that deal with Japan. China would have been a semi-colony of Japan at best, perhaps for decades, and the western powers would probably have been cut out of trade and markets there. However, Chinese defeat would also have affected the global war. If China had surrendered, Japan’s need to keep pouring troops and resources into the conflict there would have ended and the American pressure that led to Pearl Harbor would have been harder to achieve. Without a war in Asia that brought in the US, any American entry into the European war would have been more difficult, making a Nazi victory more plausible.

When the Japanese attacked Pearl Harbor, Chiang knew that it was a turning point for the ultimate defeat of Japan. But, if he had not kept fighting between 1937 and 1941, Pearl Harbor might not have happened at all.

‘The point of Pearl Harbor was to force an acceptable arrangement with the US in the Pacific and South-East Asia’

Christopher Harding, Senior Lecturer in Asian History at the University of Edinburgh and author of The Japanese: A History in 20 Lives (Allen Lane, 2020)

There is so much to the equation – in Europe and Asia, on land and at sea – that it is difficult to say with any certainty that Pearl Harbor, an event that took place so early in a long war, spelled the end for the Axis. Still, from the Japanese point of view at least, it is difficult to imagine a scenario whereby the attack on Pearl Harbor ended up helping the Axis cause. 

In a war that turned to a great degree on industrial capacity, Japanese miscalculation brought an up-and-coming industrial superpower into a global struggle. That decision, to attack Pearl Harbor, was enormously controversial among Japan’s top brass. Influential voices had insisted that the war in China and one potentially against the Soviet Union ought to remain the strategic priority. 

If we factor in the violently chaotic nature of Japanese politics in the years running up to Pearl Harbor (including an attempted coup), along with inter service rivalry between the imperial army and navy (both of which reported independently to Emperor Hirohito) it is possible, though unlikely, that a shuffling of the Japanese leadership could have occurred that would have led to Japan seeking early terms with the United States under President Roosevelt. The ultimate point of Pearl Harbor, after all, was to force an acceptable arrangement with the United States in the Pacific and South-East Asia, rather than to provoke all-out war. 

Had such terms been reached for withdrawal from the war, with Japan almost certainly forced to accept American demands from before the attack on Pearl Harbor to pull back in China, then I wonder how that might have changed the war in Europe. Alongside the British, would the US have had more resources to plough into that theatre, thus bringing the Second World War to an earlier close? Or might the American public have reverted to a ‘not our fight’ isolationism, supported by the likes of America First, potentially changing the outcome of the conflict? 

‘It enabled the world’s leading economy to create the most powerful military machine in history’

Charlie Laderman, Senior Lecturer in International History at King’s College, London and co-author of Hitler’s American Gamble: Pearl Harbor and the German March to Global War (Allen Lane, 2021)

Hitler’s response to Pearl Harbor, more than the attack itself, is what sealed the Axis’ fate. By late 1941 the US and Germany were engaged in an undeclared naval war. Washington was supplying the Allies with extensive supplies. Yet, without a formal declaration of war, Roosevelt could not fully mobilise America’s economy and its production could satisfy only a portion of Allied demand. In late November 1941 only a quarter of Americans favoured declaring a US-German war. 

Japan’s Pearl Harbor attack did not resolve the situation. It united Americans, but against Japan, not Germany. It did not, as Senator Arthur Vandenberg claimed, ‘end isolationism for any realist’. America First founder, R. Douglas Stuart Jr., told colleagues that: ‘The facts and arguments against intervention in Europe remain the same as they were before the Japanese issue arose.’ Non-interventionists argued that Roosevelt’s meddling in Europe had left the US even more exposed in East Asia. Indeed, defence aid to Europe was immediately suspended. 

While Hitler had secretly promised to support Japan if it attacked the US, he was not treaty bound to do so. Tokyo could not be sure that Hitler would deliver. Ultimately, he did so because he calculated that if the US focused only on Japan it would triumph quickly and turn its full attention on Germany. In declaring war, he enabled the US to enter the conflict united. 

Hitler’s catastrophic gamble ensured that two separate conflicts became a world war. Even if formal US-German hostilities would have ensued at some point after Pearl Harbor, timing was critical. If the uncertainty had persisted for weeks or even months, then this might have prolonged the aid embargo, with serious consequences for Britain in North Africa and the Soviet Union’s defence of Moscow. It was Hitler who brought the US fully into the war, against every Axis power and in every theatre. It enabled the world’s leading economy to create the most powerful military machine in global history and cemented the alliance that ensured the Axis’ destruction.