Pearl Harbor: The First Energy War

Charles Maechling argues that the Japanese attack, which took place on December 7th 1941, was partly a response to the country's limited energy resources.

Photograph from a Japanese plane of Battleship Row at the beginning of the attack. The explosion in the center is a torpedo strike on the USS Oklahoma. Two attacking Japanese planes can be seen: one over the USS Neosho and one over the Naval Yard.December 7th, 1941 – in the words of President Franklin Roosevelt’s stirring war message to Congress, ‘ … a date that will live in infamy’ – marks the devastating Japanese naval air raid on Pearl Harbor, Hawaii, that sank or crippled the US battle fleet and plunged the United States into the Second World War.

In the summer of 1941, Japan had been at war on the mainland of Asia for four years. After amputating Manchuria from China in 1932, it had begun a full-sale and brutal invasion of China itself. A Japanese army of over a million now occupied the principal Chinese cities and large stretches of the interior. The Nationalist government of Chiang Kai-shek  still, however, refused to sue for peace in spite of the loss of so much territory, and the drain of Japanese manpower and supplies continued unabated.

Just as today, Japan in 1941 was heavily dependent on outside sources for the minerals, petroleum and other raw materials needed to fuel its economy. The aim of Japan’s programme of conquest, therefore, was to convert China into an economic vassal, the first step in carving out a continental economic system – the Greater East Asia Co-Prosperity Sphere, also to embrace Korea, Indo-China, Malaya, and Indonesia. The plan was to insulate the region from world-wide depression by allowing raw materials to flow into Japan for conversion into manufactured goods for the limitless Chinese market, thereby ensuring freedom from Western economic domination.

Japan’s limited energy resources was the plan’s Achilles’ heel. Despite minimal civilian petrol consumption, and a largely unmechanised army, Japan’s oil consumption since 1931 had climbed steadily from a level – unbelievably low by modern standards – of about 21 million barrels a year to over 32 million barrels in 1941. (Japan’s current annual consumption is about three billion barrels.) The most imperative defence requirement was to ensure ample reserve stocks for the powerful and growing Imperial Navy, and to this end Japan had accumulated a stockpile of around 54 million barrels with 29 million reserved for the Navy.

In 1941, Japan’s dependence on outside sources for petroleum products was similar to what it is today. 90 per cent of the country’s needs were made up by imports which in the late 1930s varied from a low figure of 30.6 million barrels in 1938 to 37.1 million in 1940, the excess going into the stockpile. But there was one enormous difference from today – before the Second World War, the vast reserves of Saudi Arabia and the Middle East had yet to be developed, and 85 per cent of Japan’s imports came from one monolithic supplier. Japan’s private OPEC was the United States of America, then the world’s leading exporter. And by 1941 relations with the United States had deteriorated to the verge of war.

It had not always been so. The United States had opened Japan up to the outside world in the nineteenth century. President Theodore Roosevelt had been responsible for securing a favourable settlement for Japan after the Russo-Japanese War of 1905, and Japan had been a de facto ally in the First World War. Despite resentment over restrictive US immigration laws, among the educated classes there was a considerable reservoir of good will for the United States, now Japan’s most important trading partner, and vast admiration for American education and technological achievements.

But since the ‘Manchurian incident’ and the Japanese creation of Manchukuo in 1932, the United States had been the principal opponent of Japanese expansion in Asia. Under the Stimson Doctrine, the United States had refused to recognise the puppet regime in Manchukuo and regarded the programme for a Greater East Asia Co-Prosperity Sphere with hostility and moral disapproval – attitudes reinforced by the atrocities perpetrated by the Japanese army in China. Isolationist sentiment and the constraints imposed by recently enacted neutrality legislation not only barred the FDR administration from giving military assistance to threatened foreign countries, but inhibited any form of economic sanctions against aggressor nations. Moreover, President Roosevelt was under pressure from Britain and his own cabinet to avoid any kind of military confrontation in the Pacific that might detract from aid to the Allies and divert public attention away from Hitler.

The US Navy was even more cautious. Successive chiefs of naval operations had warned the President that until the 1934 building programme was completed, and bases in the Philippines, the Central Pacific and Hawaii reinforced, any military confrontation with Japan would find the navy at a grave disadvantage. It had neither the carrier air strength nor the auxiliary supply vessels to fight its way through the Japanese-mandated Marshall and Caroline Islands, bristling with air bases, to confront the formidable Japanese navy in its home waters.

The reluctance of the admirals became even more pronounced after the German submarine campaign in the Atlantic got under way. Destroyers of the Pacific Fleet, essential to protecting heavy ships from submarine attack, were now being transferred to the Atlantic for patrol and convoy escort duty. A recent commander of the fleet, the redoubtable Admiral James O. Richardson, had been replaced for pouring cold water on the President’s fantasy of running a cruiser patrol line across the Pacific from Hawaii, and for insisting that the fleet be withdrawn to its West Coast bases because of the vulnerability of Pearl Harbor. Once the decision was made to give the lifeline to Britain top priority, a temporising stance in the Pacific was inevitable.
In July 1940, however, the passage of the Export Control Act gave the President an excuse to retaliate against Japanese expansion without appearing to be punitive. When in September 1940 the Japanese army moved into northern Indo-China, Roosevelt could cite US defence needs under the Act as justification for imposing an embargo on the export of scrap iron and steel. Shortly thereafter he prohibited the exportation of aviation fuel and lubricants to all but Great Britain and the Western Hemisphere countries. But the flow of oil and regular petrol to Japan continued without interruption, and its oil imports in 1940 only dropped to 23 million barrels from 26 million the year before.

Meanwhile Japanese foreign policy had been undergoing a re-appraisal through a convoluted and agonising process. The Japanese military – or more properly the army high command – had, since the Manchurian takeover, exercised a baleful influence over foreign policy which on several occasions (most famously in the February 26th Incident of 1936) led fanatical young officers to assassinate elderly and conservative cabinet ministers who were considered ‘unworthy’ of Japan’s imperial destiny. The army high command risked loss of face, and even disgrace in the eyes of the Emperor and the people, the longer the war in China was permitted to drag on. The high command therefore became the principal proponent of closer ties with Germany and Italy and an aggressive move south to achieve the cherished dream of self-sufficiency.

On the other side, strong forces were at work in support of a policy of moderation. These included the nobility, the business and financial leadership, even the Imperial Navy. Though dismayed and resentful over American attitudes, these circles had a more healthy respect for American industrial might and global influence than the insular army, and dreaded the unforeseeable consequences of war with the US. The unrelenting disapproval of America to Japan’s programme for Asia was upsetting but could be tolerated as long as the oil supply remained intact. Compared to the long-standing geographical, historical and economic bonds that linked Japan to the United States, the new ties with its allies of expediency, Germany and Italy, seemed artificial and flimsy.

Before a clear-cut policy could emerge, however, these differences had to be thrashed out within the imperial circle. Although crudely styled ‘fascist’ by the American press and politicians, and lumped in with Germany and Italy as a grinning partner in iniquity, Japan and its political system had little in common with European dictatorships. Except for the predominant influence exercised by the military caste, which was deemed to incarnate the samurai virtues, Japanese pre-war society, and especially its decision-making process, was almost morbidly traditional.

Under a layer of parliamentary formalities, vital questions concerning the future of the empire were decided by a painful process of soul-searching and mutual consultation between leaders of the principal power groups. The resulting consensus, couched in the euphemistic and abstract syle unique to Japanese culture, was then submitted to the Emperor for a kind of mystical endorsement at an elaborate ritual called a ‘Throne Conference’.

Predictably, this system often produced policy compromises that embodied fatal contradictions. Typical was the decision reached in the summer of 1940 to install a civilian premier of impeccably conservative stripe, Prince Konoye. He was prepared to acquiesce in the army’s programme for further conquest of the Asian mainland while at the same time making an effort to reach an accommodation with the United States. But when Konoye gave the army a limited mandate to obtain bases in French Indo-China, and in September 1940 signed a defensive alliance with Germany and Italy known as the Tripartite Pact, he made it extraordinarily difficult for Roosevelt and Secretary of State Cordell Hull to make meaningful concessions in negotiations without being labelled appeasers.

Japan next took steps to reduce its oil dependence on the United States. Civilian consumption of petrol was cut from 6-7 million barrels annually to 1.6 million. By diversifying supply it managed by the end of 1940 to reduce the proportion of oil imports from the United States to 60 per cent. But the disruption of the oil market by competing demands of neutral and warring powers alike, combined with the inaccessibility of remaining sources, made a search for alternatives essential. For years Japan had cast a covetous eye on the oil reserves of the Dutch East Indies, and in June 1940, after the German occupation of The Netherlands, demanded assurances from the Dutch colonial government in Batavia, now cut off from the mother country, that exports of oil and minerals to Japan be maintained at pre-war levels. In September 1940 the Konoye government despatched a large mission to Batavia with ‘proposals’ for access to raw materials on a greatly increased scale, with oil to be given top priority.

Before the outbreak of the war, Japanese imports from the Indies had been running at about 4.5 million barrels annually. Japan now demanded a guarantee of 22 million barrels, which would have represented about 40 per cent of the annual production of the Indies (55 million barrels) – a figure almost exactly equal to Japan’s oil dependence on the United States. However, the Dutch colonial administrators, although well aware of the Indies’ vulnerability, displayed characteristic toughness and obstinacy. They protracted the negotiations over three months, and when finally in November they agreed to an increase, the Japanese were granted only 14.5 million barrels annually; even this amount was made subject to the concurrence of the oil companies and hedged about with escape clauses.

In the winter of 1940-41, American attention increasingly focused on the plight of Britain whose trans-Atlantic lifeline was suffering catastrophic losses from the German submarine campaign. In April 1941, Germany invaded Yugoslavia and Greece and inflicted heavy defeats on the British in Crete and North Africa. President Roosevelt extended the US neutrality zone in the Atlantic and the degree of convoy protection further to the east. In May he proclaimed augmented submarine tracking and convoy protection in the zone and transferred fleet units from the Pacific to the Atlantic; a national emergency was declared. In Washington, support for Britain was now given indisputable priority.

Meanwhile, in Tokyo the policy pendulum oscillated. A new Japanese ambassador, Admiral Kichisaburo Nomura, known to be friendly to the United States, was sent to Washington with a fresh set of tentative proposals. They offered a freeze on Japanese military operations in China and initiation of negotiations with Chiang Kai-shek, who still exercised a precarious sway over its unoccupied provinces. In return, Japan asked for a lifting of embargoes on critical materials, resumption of normal trade with the United States, US assistance in restoring the flow of raw materials from South East Asia, and exertion of influence on Chiang Kai-shek to open peace negotiations with Japan. Secretary Hull agreed to discuss these proposals, but after fifty secret meetings with Nomura, no basis for agreement could be found.  Hull declined to be drawn into specifics and countered with a demand for agreement in principle on four points before negotiations could begin – Japan was to pledge respect for the territorial integrity of all nations, non-interference in other nations’ internal affairs, equality of commercial opportunity, and a commitment to peaceful change of the status quo. Japan viewed these formulations as a lawyer’s device to raise obstacles to negotiating trade-offs, and the talks ended in temporary stalemate.

At the same time, new factors hardened each nation’s position. In April 1941 Japan and Russia signed a surprise non-aggression pact, and in June Germany invaded the Soviet Union. These developments signified to the Japanese high command that at long last the Soviet threat along the Manchurian border had been neutralised. Also in June the United States suspended petroleum exports to Japan from East Coast and Gulf ports. The Japanese establishment went into conclave and in July, at another Throne Conference, the army high command, with the concurrence of Prince Konoye, proposed to the Emperor that the empire now had no choice but to resume the march southwards. The Emperor seemed to assent, and planning was ordered for invasion of Malaysia, the Philippines, the Dutch East Indies and Hong Kong, combined with preparations for war with the United States, Britain and the Netherlands. But no specific deadlines were set and negotiations were to continue.

On July 24th, the Japanese army, with the reluctant acquiescence of the Vichy government in France, occupied key positions throughout Indo-China. And on July 26th, President Roosevelt ordered the freezing of all Japanese assets in the United States and the placing of all petroleum exports to Japan under embargo subject to licence. The British and Dutch governments quickly followed suit. To this day the record is unclear as to whether the President realised the full implications of his actions. Some memoirs of his entourage indicate that he intended to use the licensing authority as a diplomatic weapon – a tap to be turned on or off for bargaining purposes. But the freeze made it almost impossible for Japan to continue paying cash for oil as before. In any case, this was a victory for the hardliners in the administration – Secretary of War Stimson, Secretary of the Treasury Morgenthau, and Secretary of the Interior Ickes – who had been pressing for an oil embargo for months in the belief that it would force Japan to its knees.

It soon became apparent that in such a political climate, no licences would be issued and none ever was. Japan was now thrown back on her stockpile. To quote the historian Herbert Feis:

There was no way, no uncontrolled source of supply, from which Japan could get as much as it would have to use … Ton by ton, it could be foreseen, Japan would have to empty the tanks which had been filled with such zealous foresight … From now on the clock and the oil guage stood side by side. Each fall in the level brought the hour of decision closer.

For the American military, the timing of the President’s action represented a setback. The navy in particular had repeatedly stressed US  inferiority in the Pacific – it was outnumbered in aircraft carriers by ten to three – and the army had urged delay until air and ground forces in the Philippines could be strengthened. From Tokyo, Ambassador Joseph E. Grew had once more cautioned that if pushed to the wall it was in the Japanese character to react violently and without warning. But President Roosevelt believed that although he was running a risk, it was one that did not close off his options or entail serious consequences for the United States. He was reassured in this belief by the virtual unanimity of his advisers that if war came it would be far away, a Japanese move against Malaysia and the Dutch East Indies; the safety of the United States was not an issue.

The freezing of its assets and the oil embargo were greeted in Japan with shock and dismay. Records published after the war reveal an atmosphere of desperation. By August 1941 there was only a twelve-month supply of oil left for the army and eighteen months for the navy. A Throne Conference called early in September set war planning in motion, and in October a hardline cabinet headed by war minister General Hideki Tojo replaced the discredited ministry of Prince Konoye who had set his hopes on a secret summit meeting with President Roosevelt. A final Throne Conference on November 5th committed a still ambivalent emperor to war unless a last-minute diplomatic solution could be found.

Japan’s final effort consisted of proposals embodying new concessions, carried to Washington by a special envoy, Saburo Kurusu, who henceforth participated with Admiral Nomura in negotiations. These agreed to immediate Japanese withdrawal from Indo-China, renunciation of further expansion in Asia, and ultimate withdrawal from China after conclusion of a peace treaty with Chiang Kai-shek. It also made clear that Japan was prepared to treat the Tripartite Pact as a nullity.

But like previous efforts, these proposals foundered on the rock of irreconcilable conflict. Japan would not totally withdraw from the Asian mainland and revert to a pinched and impoverished existence in its overcrowded islands. The United States could not accept a compromise that left Japan in possession of any part of China. However, a three-months moratorium, a modus vivendi, leaving all forces in place, was left on the table. But on November 26th, after Japan occupied more positions in Indo-China, Secretary Hull stunned the Japanese envoys with a blunt reversion to earlier demands, including complete Japanese withdrawl from all of China.

Throughout these events, President Roosevelt and a close circle of top advisers – the secretaries of State, War and Navy, and the Chief of Staff of the Army and Chief of Naval Operations – had been following every twist and turn of Japanese policy through cable and radio intercepts. American cryptographers had broken the Japanese diplomatic code, and thereafter, these decoded messages to Japan’s overseas posts, styled MAGIC, were on Secretary Hull’s desk within a few hours of receipt and translation. But although the President and his advisers knew of Japan’s desperation, and intention to take drastic military measures if negotiations broke down, they did not know where and when the blow was most likely to fall. The Japanese army and navy codes were still unbroken, and while the indicators from troop movements pointed to Malaysia, the Dutch East Indies and possibly the Philippines, and to the critical dates of the weekends of December 1st and December 7th, there was no indication of an attack on the United States or its possessions.

Nonetheless, to cover all contingencies, on November 27th the war and navy departments in Washington despatched a general war warning to the commanders of the US Pacific Fleet in Pearl Harbor and the army’s Hawaiian department, and to General MacArthur and the commander of the US Asiatic Fleet in Manila. Not a hint of impending war was given to Congress, the press, or the American public.

The Japanese air raid on Pearl Harbor, which killed over 3,000 American soldiers, sailors and airmen, and destroyed or disabled six battleships and most of the military aircraft on the ground, lives in American legend as the country’s greatest wartime disaster. But for Japan, the attack turned out to be a military and political disaster of much greater magnitude. The Pacific Fleet’s aircraft carriers – the true capital ships of the coming war – were elsewhere on the morning of December 7th. In the teeth of all the evidence of American naval inferiority in the Pacific, the commander of the Japanese navy, Admiral Yamamoto, had clung to the doctrine that before his main objectives could be achieved, an enemy ‘fleet in being’ on his flank had first to be destroyed. Instead of confronting President Roosevelt with the dilemma of persuading a refractory Congress to declare war in defence of the British and Dutch colonial empires, while leaving the Nazi menace unresolved, he brought a unified America headlong into war.

Even after eight official investigations, lengthy Congressional hearings, and voluminous literature of memoirs and other first-hand accounts, historians continue to debate reasons for the débâcle and  American lack of preparation. Revisionist works continue to appear that allege that in one way or another President Roosevelt provoked the attack, the most recent focusing on intercepts that should have triggered immediate alarm in Washington. One fact that now appears indisputable is that throughout the crisis, the Hawaiian commanders, Admiral Kimmel and General Short, were denied vital information, though whether by design, rigid chains of command, or fear of revealing even the existence of MAGIC, has never been established.

One lesson that does stand out is that while oil was not the sole cause of the deterioration of relations, once employed as a diplomatic weapon, it made hostilities inevitable. The United States recklessly cut the energy lifeline of a powerful adversary without due regard for the predictably explosive consequences. When the victim struck back, he blundered badly and unleashed forces of incalculable magnitude that we still live with today.

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