According to President Franklin D Roosevelt 7th December 1941 was a “a date which will live in infamy”. On that day the American naval base at Pearl Harbor on Oahu Island, Hawaii, was attacked by Japanese forces. Many people think that this attack came completely out of the blue but it was, in fact, culmination of more than a decade of steadily worsening relations between the United States and Japan.

American foreign policy in the Pacific in the late 1930’s was to support China against an increasingly aggressive Japan which had taken control of the Chinese province of Manchuria in 1931, although open warfare did not break out between Japan and China until July 1937. America continued to support China by giving the country a loan in 1938, and terminating their 1911 treaty of Commerce and Navigation with Japan in July 1939. By 1940 America was restricting exports to Japan which could be used in the war, and tensions between the two countries continued to mount. Matters were not helped when the Japanese allied themselves with the Axis powers (Germany and Italy). This caused America to sever all relations with Japan, freeze her assets and place an embargo on Japanese shipments carrying materials of war.

Many of the hierarchy in the Japanese military resented the fact that America was supporting China and wanted to end their interference. They also saw the German invasion of the Soviet Union as an opportunity for Japan to extend her reach in the Far East without the intervention of Russia. Even so, there were attempts by some to smooth things over between America and Japan right through the autumn of 1941, although the Japanese Prime Minister had already privately decided that war was the only way forwards – his theory was that if the Japanese could destroy the American Pacific Fleet it would leave them able to conquer all of South East Asia unopposed. The attack on Pearl Harbor was planned by the Commander-in-Chief of the Combined Fleet of Japan, Admiral Yamamoto, with the fleet coming together in the Kuril Islands on 16^th November, although Yamamoto was prepared to be recalled if negotiations with the Americans proved successful. Admiral Nagano, the Chief of the Naval General Staff did not want to risk the fleet so far from home, particularly as that would limit the forces they could use for other actions in the Far East, but Yamamoto threatened to resign if his plan was axed so all opposition was ignored.

On 26^th November 1941 the American Secretary of State wrote to the Japanese to try to smooth things over, however his requirement that Japanese troops should be withdrawn from China and Indochina did not go down well. The note was seen as irrelevant by the Japanese anyway as their forces had already set sail to attack Pearl Harbor on the same day.

The US Pacific Fleet along with military and naval forces were stationed at Pearl Harbor as the tensions between the two nations steadily mounted. Admiral Kimmel and Lieutenant General Short were warned three times (16th October, 24th November, and 27th November) that war was possible and they should take appropriate defensive measures. Short ordered his forces to be on the alert for sabotage, and moved all of his planes to Wheeler Airfield to protect them, as well as ordering that radar should be monitored from 4 – 7am (the most likely time of day for an attack). Kimmel was equally relaxed in his preparations – although he was not able to locate the main parts of the Japanese Fleet he did not send his reconnaissance north-west (which would  have been the logical direction for an attack to come from); he also allowed personnel on shore leave after mooring the entire fleet in the harbour.

On the US mainland the Japanese Ambassador had asked for a meeting with the American Secretary of State in Washington at 1pm on 7^th December (7.30am Pearl Harbor). General Marshall, the American Army Chief-of -Staff sent a telegram to Kimmel to say that war was imminent, but it did not arrive in Pearl Harbor until after the attack began. There were other signs, however, that Kimmel should have realised could be fore-runners of an attack. The first happened four hours before the attack when a Japanese submarine was sighted near the Harbor, it was later fired upon by the USS Ward. Then at 7am, when the radar should have been switched off, Private George Elliott decided to get in some more practise; he noticed a large group of planes on the screen but was told to ignore them as a flight of bombers was expected to arrive that morning. Kimmell was still awaiting confirmation of the submarine encroachment when the air attack began. (Kimmel and Short were later blamed for mistakes and errors of judgement at Pearl Harbor and were dismissed.)

The Japanese had already landed forces in Malaya and Thailand a couple of hours before the attack on Pearl Harbor began (for them, Pearl Harbor was seen as a supporting operation). The attack against America was, however, incredibly well planned with an entire fleet including six air craft carriers, two battleships and three cruisers travelling 3,700 miles across the North Pacific undetected. It was necessary to refuel on the way which could not be done in rough weather and so the Americans did not think an attack could come from that direction. However, they were wrong, and at 7.55am on the morning of 7^th December 1941 the attack began with 183 aircraft of the Imperial Japanese Navy attempting to damage or destroy as much of the US Pacific Fleet as possible.

In the first attack the planes and hangers on the island’s airfields were targeted by bombers as torpedo planes attacked the warships at anchor. Four battleships were hit in the first five minutes, followed minutes later by the sinking of the USS Arizona when her gunpowder supplies took a direct hit, killing 1,177 of her crew. The attack was devastating, but it was not the end as less than two hours later a second wave of 170 aircraft arrived. The Americans fought back but were completely unprepared (only 6 planes managed to get into the air) and in just two hours 18 American warships had been either damaged or sunk, almost 200 aircraft destroyed and over 2,400 American service men and women killed. The Americans were lucky that the three aircraft carriers, seven heavy cruisers and a division of destroyers attached to the Pacific Fleet were not in harbour and so escaped without damage. The Japanese in contrast lost less than 60 planes, 5 midget submarines, possibly 2 fleet submarines, and less than 100 men; the main fleet returned to Japan without being attacked.

The attack on Pearl Harbor had an immediate impact on the course of the Second World War. Up until that time the Americans had been supporting the Allies through the Lend-Lease Agreement by supplying war supplies, but most Americans did not want to get actively involved in the fighting. However, they were outraged by the Japanese attack and the next day the US declared war on Japan, finally entering the conflict on the side of the Allies.

The Tripartite Pact signed by Japan, Italy and Germany in September 1940 meant that Germany was obliged to go to war if America attacked Japan but not if Japan attacked America. Roosevelt did not want to be seen as the one to declare war on Hitler but knew that such a conflict would be inevitable if the US declared war on Japan. As he had foreseen, Hitler declared war on  American in support of Japan on 11^th December and the President was able to get the full support of Congress to declare war on Germany.

The Japanesse attack was devastating, but six of America’s eight battleships (excluding the Arizona and Oklahoma) were repaired and returned to service whilst the strategically important oil storage facilities on the island remained intact. The most important result of the attack, however, was it’s impact on the American public – the deaths of thousands of Americans in a surprise attack early on a Sunday morning without any formal declaration of war could only have one outcome – a uniting of public opinion behind the war effort, and the beginning of the end for Germany.