Why did Japan decide to attack Pearl Harbor

Why did Japan decide to attack Pearl Harbor? L/O – To examine perspectives on the reasons for Pearl Harbour

What happened at Pearl Harbor? • At 07. 55 on Sunday 7 th December 1941, Japan launched a surprise attack on the US Naval Base at Pearl Harbour, Hawaii – home to the US Pacific Fleet. • Planned by Admiral Yamamoto Isoroku, who believed that war with the US was foolhardy – but if it was to be, a surprise crippling blow was needed – the navy could only hold out for 1 ½ years. • The Naval Task Force was led by Vice Admiral Nagumo Chuichi, who had left Etorofu Island in the Kuriles on 26 th November with 31 ships and 6 aircraft carriers – 5 days before the Emperor had even ratified the decision for war.

What happened at Pearl Harbor? • The plan was to cripple and destroy the better part of the US Pacific Fleet, thereby preventing the USA from stopping Japanese expansion in Asia. • By the time the attack stopped at 10. 00 am, 18 US ships had been sunk or seriously damaged and 188 planes destroyed and a further 159 damaged. 2, 459 US servicemen were killed. • Yet Japan had failed to destroy any US aircraft carriers, didn’t destroy any naval repair ships, nor did Japan target vital infrastructure like power plants and oil storage facilities. ‘The surprise attack on Pearl Harbour… was a strategic imbecility…. On the tactical level, the… attack was wrongly concentrated on ships rather than permanent installations and oil tanks. On the strategic level it was idiotic. On the high political level it was disastrous. ’ Samuel Eliot Morrison, History of the US Naval Operations in WWII

Was Pearl Harbor a surprise? • Traditional View – Pearl Harbor was an aggressive action planned and conducted in secret therefore it was a huge ‘surprise’ to American leaders. ‘Magic’ gave no indication that Pearl Harbor was a target. For sure a tactical, if not strategic, surprise. US believed Japan was inferior power, just bluffing. Attack suspected but not known where. Admiral Kimmel and General Short were blamed and fired for not expecting the attack. View backed up by 9 official inquiries 1941 -46. • Revisionist Views – Popularised by the founder of the anti-war ‘America First’ movement, John T. Flynn, who argued that Roosevelt knew an attack was imminent and had a ‘sinister design’ in provoking the Japanese into war so the USA could become involved in the European War. Also see George Morgenstein and Charles A. Beard. • Post-Revisionist Views – Roosevelt knew that sanctions on Japan had a high chance of leading to war, US had declared for Allies since Lend. Lease in March 1941, Roosevelt personally favoured alliance with UK, needed a way to persuade US public for war, didn’t know about Pearl Harbor attack specifically, but probably welcomed it all the same.

Why did Japan attack Pearl Harbor? • There are two perspectives on the causes of the Pacific War, starting with Pearl Harbor. 1. Japan Responsible – Japan had a longstanding plan to expand their empire in the Pacific, the US economic embargo was just a pretext for war rather then a trigger (Intentionalist View – Geo-Politics) 2. US Responsible – Economic sanctions were inevitable viewed as a threat to economic and territorial expansion by the Japanese military, who felt compelled to adopt a plan to acquire needed resources and fight the USA if necessary (Determinist View – Economics)

USA Responsible for the Pacific War • USA used its economic power to create diplomatic leverage over Japan, but this had a ‘malign synergistic effect’, transforming an authoritarian Japan into a hegemonic power. • Western powers were unwilling to accept a new associate and rival in Japan – Japan could not secure a comprehensive footing in a tightening global market for its products. Naval limitation treaties in 1922/30 and Great Depression also limited Japan’s ability to extend into world markets. • This forced Japan into considering becoming a landbased power in China. Rise of GMD and USSR was threatening a peaceful growth in Japanese influence – therefore had to ‘coordinate’ China more forcefully – leading to 1931/37.

USA Responsible for the Pacific War • Japan sucked into unwinnable conflict in China – USA sought to maintain its trade privileges in China ‘Nine-Power Treaty’ system and ‘Open Door’ which China the war was destroying. • USA then used its economic power to force Japan to withdraw. Embargo on aircraft parts and aviation oil in July 1938, US ended its 1911 Commercial Treaty with Japan in July 1939 and a new naval reconstruction programme in July 1940. Export Control Act in July 1940, then sanctions on scrap iron and steel in September 1940. Finally, oil embargo and seizure of Japanese assets in July 1941. • This forced Japan into decision – withdraw from Asia and loose all gains, or go to war with USA.

Japan Responsible for the Pacific War • Japan had decided from at least 1931, if not before, to risk war to secure its freedom of action. It decided to forego cooperation in Asia. • It chose a policy of economic autarky, seeking to win complete control over access to resources, rather than through trade – wasn’t willing to bank on goodwill of Western nations – Great Depression confirmed this with imperial preference system. • Japan sought to develop ideology based on Pan-Asianism, ‘Asia for the Asians’ through the Greater East Asia Co-Prosperity Sphere. This developed a powerful anti-Western rhetoric.

Japan Responsible for the Pacific War • Thus US sanctions weren’t a trigger for war. Japan had already established a policy for achieving autarky before 1937. • US sanctions were expected – its leaders believed Japan had to become selfsufficient or become a puppet of foreign states. • The policy of autarky required Japan to use force – all vital war materials were in the hands of the USSR, China, France, UK, USA or Dutch. The Japanese knew this meant war and took advantage of the war in Europe to achieve these aims.

Japan Responsible for the Pacific War • This meant Japan had to go against the ideas of economic equality, free trade, and China’s sovereignty, guaranteed by Japan in the 1922 Nine-Power Treaty. • Yet USA needed to maintain the Open Door Policy as matter of principle (anticolonialism) and as a matter of strategy to ensure the flow of resources to aid the Allied cause in Europe. • After 1941, USA also had to ensure Japan wouldn’t attack its ally, the USSR. This required a strong US stance vs. Japan.

Japan Responsible for the Pacific War • Therefore sanctions were not the trigger for war. US and Japanese policies were on a collision course ever since Japan decided to pursue economic autarky and imperialism in China. • Because Japan could not be pursued to give up its ambitions, war became inevitable and just a matter of timing. • Therefore Japan was responsible for the Pacific War and Pearl Harbor.

Why did Japan attack Pearl Harbor? • Using your timelines on the road to war, what events and examples could we use to support each perspective? 1. Japan Responsible – Japan had a long-standing plan to expand their empire in the Pacific, the US economic embargo was just a pretext for war rather then a trigger (Intentionalist View – Geo-Politics) 2. US Responsible – Economic sanctions were inevitable viewed as a threat to economic and territorial expansion by the Japanese military, who felt compelled to adopt a plan to acquire needed resources and fight the USA if necessary (Determinist View – Economics)