The USA and Japan (AQA A-Level History): Revision Notes
The USA and Japan
Background to conflict
By the end of the 1930s, Japan was developing closer ties with European fascist regimes. American policymakers grew increasingly alarmed as they observed Japan's military expansion into Indochina (French colonial territory in South-east Asia). Roosevelt expressed his opposition through economic measures against Japan, hoping such pressure would halt Japanese military activities. Japan's military leadership controlled governmental decision-making, with a stated objective of preventing any American interference with imperial and economic expansion.
Roosevelt's strategy relied on economic pressure rather than military confrontation, believing that financial and trade restrictions could effectively constrain Japanese expansion without direct military engagement. This approach would become increasingly significant as relations deteriorated throughout the late 1930s and early 1940s.
Deteriorating USA-Japan relations
Relations between Washington and Tokyo had been declining since Japan's invasion of China, which began in 1937. Japan declared that the open door policy (the principle guaranteeing equal trading access to China for all nations) was no longer valid. Roosevelt responded with multiple measures: he provided financial assistance to China for purchasing weapons and requested American manufacturers to refuse selling aircraft to Japan. Japan relied heavily on importing industrial materials from America, and when these supplies dried up, Japanese authorities recognised the need to secure alternative sources, using military force if required.
Japan's Critical Dependence on American Resources
Japan's economy was heavily reliant on imports from the United States, particularly oil and industrial materials. When these supplies were restricted, Japan faced a strategic dilemma: either submit to American demands or seek alternative sources through military expansion. This dependency would become the central factor driving Japan toward war with the United States.
In July 1940, Congress imposed restrictions on exports of oil and scrap iron to Japan. Following Japan's signing of the Rome-Berlin-Tokyo axis agreement, Roosevelt prohibited the sale of machine tools to Japan. During spring 1941, Secretary of State Cordell Hull conducted negotiations with Japanese Ambassador Kichisaburo Nomura aimed at resolving differences between the two nations. Hull insisted that Japan must withdraw from China and guarantee not to attack Dutch and French colonial territories in South-east Asia. Japan rejected these demands because America offered nothing in exchange.
The Greater East-Asia Co-Prosperity Sphere
European powers were engaged in continental warfare and could not defend their Asian possessions, such as the Dutch East Indies. When Germany defeated France, Japanese forces moved into French colonies in Indochina. Japan subsequently announced the establishment of the Greater East-Asia Co-Prosperity Sphere. This concept effectively provided Japan with mechanisms to economically exploit territories under its control.
In July 1941, America responded by freezing Japanese financial assets held in the USA and imposing an embargo on oil exports. Japanese oil supplies relied almost entirely on imports from America.
The Oil Embargo's Impact
The oil embargo represented a turning point in USA-Japan relations. With Japan importing approximately 80% of its oil from the United States, the embargo threatened to cripple Japan's military operations and industrial economy within months. This created an urgent timeline for Japanese decision-makers: either negotiate a settlement or secure oil supplies through military conquest of the resource-rich Dutch East Indies.
As the Japanese military increasingly dominated decision-making, the new Japanese Ambassador in Washington, Kichisaburo Nomura, informed Hull that Japan would cease further expansion if America and Britain terminated aid to China and ended the economic blockade on Japan. Nomura suggested that Japan might even commit to withdrawing from Indochina to achieve 'just peace' with China. Some historians today argue that Japan, struggling in its Chinese war, was genuinely attempting to find a face-saving exit strategy. However, few scholars believe Japan would have actually fulfilled any agreement reached with China.
Pearl Harbor attack
Few Americans at the time placed trust in Japan. When the USA rejected Japanese proposals, Japanese military planners began preparing to attack the American naval base at Pearl Harbor, located on Oahu island, Hawaii. The attack's objective was to cripple the US Navy, thereby preventing American interference with Japanese expansion into East Asia and resource-rich areas such as the Dutch East Indies with their oil supplies. Japan did not inform its European allies of these intentions.
Japanese Strategic Objectives at Pearl Harbor
The attack aimed to achieve three main goals:
- Destroy the US Pacific Fleet, particularly aircraft carriers and battleships
- Eliminate American air power in the Pacific
- Create a window of 6-12 months for Japan to consolidate control over South-east Asia and the Dutch East Indies before America could rebuild its naval strength
In the early hours of Sunday 7 December 1941, whilst most of the garrison slept, Japan launched a devastating attack on Pearl Harbor. Taking American forces completely unaware, Japanese fighter aircraft and bombers destroyed 180 American aircraft and sank seven battleships along with ten other vessels. Over 2,400 American military personnel were killed. However, American aircraft carriers were at sea and thus escaped attack. Furthermore, Japanese forces failed to destroy the American fuel storage facilities; had these been hit, the entire naval base would have needed to return to the USA, leaving the region completely undefended against further Japanese aggression.
On 8 December, America declared war on Japan. On 11 December, fulfilling his treaty commitments, Hitler declared war on America, as did his ally, Italy.
Historiographical debate on Pearl Harbor
The stunning nature of the Pearl Harbor attack has generated historical controversy about how it was possible. Right-wing historians have suggested Roosevelt deliberately withheld information about the impending Japanese attack from the Pearl Harbor commander, knowing that the shock of the attack would provide justification for war.
The Historical Debate: Two Interpretations
Right-wing perspective: Roosevelt deliberately provoked Japan and withheld intelligence warnings to create a justification for American entry into World War II, knowing public opinion needed a dramatic incident to overcome isolationist sentiment.
Alternative interpretation: The attack succeeded due to administrative failures, communication breakdowns, and misinterpretation of intelligence rather than deliberate conspiracy. Multiple levels of command failed to recognize or act upon warning signs effectively.
Alternative interpretations reject this view, arguing that whilst evidence exists of information mishandling, there was no deliberate suppression of warnings on 7 December. Limited evidence suggests Roosevelt would have deliberately placed the Pacific Fleet at risk. He understood by November 1941 that war was approaching, but delay was preferred over immediate confrontation. The Pearl Harbor disaster more likely resulted from confusion and administrative failures at multiple levels.
Operation Magic
Roosevelt and his advisers gained some reassurance from their ability to decipher Japanese radio communications through Operation Magic, an intelligence programme established during the 1920s to intercept military and diplomatic transmissions. Operation Magic also provided information about Japanese naval movements, though intelligence analysts could not determine precise destinations. US intelligence discovered that Japan had set 25 November as a deadline for diplomatic progress. When Hull briefed the Cabinet on 7 November, he warned that America should prepare for a Japanese military attack 'anywhere, anytime'.
What Operation Magic Revealed
Operation Magic successfully intercepted and decoded Japanese diplomatic communications, revealing:
- Japan's deadline of 25 November 1941 for diplomatic resolution
- Growing Japanese frustration with negotiations
- Increased military preparations and movements
However, the intelligence failed to identify Pearl Harbor as the specific target, and various warnings were not effectively communicated to commanders in Hawaii, contributing to the surprise of the attack.
Source note: Diplomat John Paton Davies described the USA/Japan/China relationship as a triangle where "Japan was the actor; China the acted upon. And the US was the self-appointed referee who judged by subjective rules and called fouls without penalties, until just before the end of the contest. This provoked the actor into a suicidal attempt to kill the referee."
Key figure: Cordell Hull
Cordell Hull served as Roosevelt's Secretary of State from 1933 to 1944. He conducted the negotiations with Japanese Ambassador Nomura during spring 1941, demanding Japanese withdrawal from China and guarantees against attacking European colonies in South-east Asia. Hull warned the Cabinet in November 1941 about the possibility of imminent Japanese military action. His firm stance reflected Roosevelt's policy of economic pressure rather than appeasement towards Japanese expansion.
Key Points to Remember:
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Japanese expansion into Indochina and alignment with fascist powers prompted Roosevelt to apply economic pressure rather than military confrontation.
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Relations progressively worsened from 1937 onwards, with America supporting China and restricting exports to Japan, culminating in the July 1941 oil embargo and asset freeze.
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Japan's attack on Pearl Harbor on 7 December 1941 killed over 2,400 Americans and destroyed significant naval assets, though American carriers escaped and fuel stores remained intact.
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America declared war on 8 December 1941; Hitler declared war on America on 11 December, bringing the USA fully into the Second World War.
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Historians debate whether Roosevelt deliberately withheld warnings about Pearl Harbor or whether the disaster resulted from confusion and incompetence, with Operation Magic intelligence providing some advance warning that was not effectively acted upon.