Attack on Pearl Harbor

On December 7, 1941, the Empire of Japan launched a surprise military strike on the United States Pacific Fleet at its naval base at Pearl Harbor on Oahu, Hawaii. At the time, the U.S. was a neutral country in World War II. The attack was carried out by planes from Japanese aircraft carriers, catching the United States completely by surprise.

The strike led the U.S. to declare war on Japan the next day, drawing the country into World War II. This event changed the course of history and brought the United States into the fight against the Axis powers. The attack on Pearl Harbor remains one of the most significant events in both American and world history.

The Japanese planned the attack carefully, hoping to weaken the U.S. Navy so Japan could expand its control in Southeast Asia without interference. Over two waves of bombers and fighters struck the naval base, damaging or sinking many ships and destroying hundreds of aircraft. The attack caused great loss of life and became a turning point that led to the United States fully engaging in the war.

Background

Main article: Prelude to the attack on Pearl Harbor

War between the Empire of Japan and the United States had been a concern since the 1920s. Japan worried about American expansion near its areas of influence, like Hawaii and the Philippines. Japan also needed resources like oil to support its growing military, especially after invading China and trying to control nearby areas.

Tensions increased when Japan moved into parts of French Indochina in 1940. The United States responded by stopping some trade with Japan, including sending airplanes and machine tools. Even so, the U.S. kept sending oil, which Japan relied on. In 1941, the U.S. finally stopped oil exports to Japan after Japan took more land in Indochina. This led Japan to plan taking oil from places like the Dutch East Indies. Both countries tried to negotiate, but they could not agree on terms. Japan wanted the U.S. to lift its trade restrictions, while the U.S. wanted Japan to leave China. These failing talks set the stage for the events that followed.

Diplomacy

War between the Empire of Japan and the United States was seen as a possibility since the 1920s. Japan had been wary of American territorial and military expansion in the Pacific and Asia since the late 1890s, followed by the annexation of islands, such as Hawaii and the Philippines, which were close to or within Japan's perceived sphere of influence.

At the same time, Japanese strategic thinkers believed that Japan needed economic self-sufficiency in order to wage modern war. The experiences of World War I had taught the Japanese that modern wars would be protracted, require total mobilization, and create vulnerabilities for trade embargoes and encirclement. As a consequence, Japan needed access to strategically important resources (e.g., iron, oil) that could not be extracted at sufficient levels in the home islands.

Although Japan had begun to take a hostile stance against the United States after the rejection of the Racial Equality Proposal, their relationship was cordial enough to remain trading partners. Tensions did not seriously grow until Japan's invasion of Manchuria in 1931. Over the next decade, Japan expanded into China, leading to the Second Sino-Japanese War in 1937. Japan spent considerable effort trying to isolate China and endeavored to secure enough independent resources to attain victory on the mainland. The "Southern Operation" was designed to assist these efforts. Nevertheless, Japan would still rely heavily on U.S. oil imports, including to Japanese forces in Japan-occupied Manchuria. In a memorandum dated October 24, 1934, Chief of the Division of Far Eastern Affairs Stanley K. Hornbeck discussed his meeting with Standard Oil New Jersey head Walter C. Teagle to U.S. President Franklin D. Roosevelt. The memo described that Teagle was uncooperative with U.S. recommendations and how Standard Oil was given special treatment by the Japanese government, which made the company less subject to Japan's national business regulation policies than other companies. Hornbeck noted in the memorandum that as a result of Teagle's business dealings with Japan, "the major portion of the petroleum and petroleum products now imported into Japan is of American origin."

Starting in December 1937, events such as the Japanese attack on USS Panay, the Allison incident, and the Nanking Massacre swung Western public opinion sharply against Japan. The United States unsuccessfully proposed a joint action with the United Kingdom to blockade Japan. In 1938, following an appeal by President Roosevelt, American companies stopped providing Japan with implements of war.

In 1940, Japan invaded French Indochina, attempting to stymie the flow of supplies reaching China. The United States halted shipments of airplanes, parts, machine tools, and aviation gasoline to Japan, which the latter perceived as an unfriendly act. The United States did not stop oil exports, however, partly because of the prevailing sentiment in Washington that given Japanese dependence on American oil, such an action was likely to be considered an extreme provocation.

In mid-1940, President Franklin D. Roosevelt moved the Pacific Fleet from San Diego to Hawaii. He also ordered a military buildup in the Philippines, taking both actions in the hope of discouraging Japanese aggression in the Far East. Because the Japanese high command was mistakenly certain any attack on the United Kingdom's Southeast Asian colonies, including Singapore, would bring the United States into the war, a devastating preventive strike appeared to be the only way to prevent American naval interference. An invasion of the Philippines was also considered necessary by Japanese war planners. The American War Plan Orange had envisioned defending the Philippines with an elite force of 40,000 men; this option was never implemented due to opposition from Douglas MacArthur, who felt he would need a force ten times that size. By 1941, American planners expected to have to abandon the Philippines at the outbreak of war. Late that year, Admiral Thomas C. Hart, commander of the United States Asiatic Fleet, was given orders to that effect.

The United States finally ceased oil exports to Japan in July 1941, following the seizure of French Indochina after the Fall of France, in part because of new American restrictions on domestic oil consumption. Because of this decision, Japan proceeded with plans to take the oil-rich Dutch East Indies. On August 17, Roosevelt warned Japan that America was prepared to take opposing steps if "neighboring countries" were attacked.

Japan and the United States engaged in negotiations during 1941, attempting to improve relations. In the course of these negotiations, Japan offered to withdraw from most of China and Indochina after making peace with the Nationalist government. It also proposed to adopt an independent interpretation of the Tripartite Pact and to refrain from trade discrimination, provided all other nations reciprocated. Washington rejected these proposals. Japanese Prime Minister Konoe then offered to meet with Roosevelt, but Roosevelt insisted on reaching an agreement before any meeting. The American ambassador to Japan repeatedly urged Roosevelt to accept the meeting, warning that it was the only way to preserve the conciliatory Konoe government and peace in the Pacific. However, his recommendation was not acted upon. The Konoe government collapsed the following month when the Japanese military rejected a withdrawal of all troops from China.

Japan's final proposal, delivered on November 20, offered to withdraw from southern Indochina and to refrain from attacks in Southeast Asia, so long as the United States, United Kingdom, and Netherlands supplied one million U.S. gallons (3.8 million liters) of aviation fuel, lifted their sanctions against Japan, and ceased aid to China. The American counter-proposal of November 26 (November 27 in Japan), the Hull note, required Japan to completely evacuate China without conditions and conclude non-aggression pacts with Pacific powers. On November 26 in Japan, the day before the note's delivery, the Japanese task force left port for Pearl Harbor.

The Japanese intended the attack as a preventive action to keep the United States Pacific Fleet from interfering with their planned military actions in Southeast Asia against overseas territories of the United Kingdom, the Netherlands, and the United States. Over the course of seven hours, there were coordinated Japanese attacks on the American-held Philippines, Guam, Wake Island, Midway Atoll and on the British Empire in Malaya, Singapore, and Hong Kong. From the Japanese point of view, it was seen as a preemptive strike "before the oil gauge ran empty."

Military planning

Preliminary planning for an attack on Pearl Harbor to protect the move into the "Southern Resource Area", the Japanese term for the Dutch East Indies and Southeast Asia generally, began early in 1941 under the auspices of Admiral Isoroku Yamamoto, then commanding Japan's Combined Fleet. He won assent to formal planning and training for an attack from the Imperial Japanese Navy General Staff only after much contention with Naval Headquarters, including a threat to resign his command. Full-scale planning was underway by early spring 1941, primarily by Rear Admiral Ryūnosuke Kusaka, with assistance from Commander Minoru Genda and Yamamoto's Deputy Chief of Staff, Captain Kameto Kuroshima. The planners studied the 1940 British air attack on the Italian fleet at Taranto intensively.

Over the next several months, pilots were trained, equipment was adapted, and intelligence was collected. Despite these preparations, Emperor Hirohito did not approve the attack plan until November 5, after the third of four Imperial Conferences called to consider the matter. At first, he hesitated to engage in war but eventually authorized the Pearl Harbor strike despite dissent from certain advisors. Final authorization was not given by the emperor until December 1, after a majority of Japanese leaders advised him the Hull note would "destroy the fruits of the China incident, endanger Manchukuo and undermine Japanese control of Korea". Before the attack, he became more involved in military matters, even joining the Conference of Military Councillors, which was considered unusual for him. Additionally, he actively sought more information about the war plans. According to an aide, he openly displayed happiness upon hearing about the success of the surprise attacks.

By late 1941, many observers believed that hostilities between the United States and Japan were imminent. A Gallup poll just before the attack on Pearl Harbor found that 52% of Americans expected war with Japan, 27% did not, and 21% had no opinion. While American Pacific bases and facilities had been placed on alert on many occasions, officials doubted Pearl Harbor would be the first target; instead, they expected the Philippines to be attacked first. This presumption was due to the threat that the air bases throughout that country and the naval base at Manila posed to sea lanes, as well as to the shipment of supplies to Japan from territory to the south. They also incorrectly believed that Japan was not capable of mounting more than one major naval operation at a time.

Objectives

The Japanese attack had several major aims. First, it intended to destroy important American fleet units, thereby preventing the Pacific Fleet from interfering with the Japanese conquest of the Dutch East Indies and Malaya and enabling Japan to conquer Southeast Asia without interference. The leaders of the Imperial Japanese Navy (IJN) subscribed to Alfred Thayer Mahan's "decisive battle" doctrine, especially that of destroying the maximum number of battleships. Second, it was hoped to buy time for Japan to consolidate its position and increase its naval strength before shipbuilding authorized by the 1940 Vinson-Walsh Act erased any chance of victory. Third, to deliver a blow to America's ability to mobilize its forces in the Pacific, battleships were chosen as the main targets, since they were the prestige ships of navies at the time. Finally, it was hoped that the attack would undermine American morale to such an extent that the American government would drop its demands contrary to Japanese interests and seek a peace compromise.

Striking the Pacific Fleet at anchor in Pearl Harbor had two distinct disadvantages: the targeted ships would be in very shallow water, so it would be relatively easy to salvage and possibly repair them, and most of the crews would survive the attack since many would be on shore leave or would be rescued from the harbor. A further disadvantage would prove to be the unexpected absence of all three Pacific Fleet aircraft carriers (Enterprise, Lexington, and Saratoga). Despite these concerns, Yamamoto decided to press ahead.

Japanese confidence in their ability to win a short war meant that other targets in the harbor, especially the navy yard, oil tank farms and submarine base, were left unscathed, since by their thinking the war would be over before the influence of these facilities would be felt.

Approach and attack

On November 26, 1941, a Japanese task force of six aircraft carriers departed from Hittokapu Bay on Etorofu Island in the Kuril Islands, heading toward a position northwest of Hawaii. The plan was to launch 408 aircraft to attack Pearl Harbor, with 360 planes for the two attack waves and 48 for defensive combat air patrol.

The first wave aimed to strike battleships and aircraft carriers, while the second wave targeted carriers, cruisers, and then battleships if needed. The attack began before Japan had formally declared war, which caused confusion and delayed communications. The first wave included bombers armed with special torpedoes designed for shallow water, and dive bombers aimed at ground targets. Fighters were tasked with destroying parked aircraft to prevent interference.

The attack caught the United States Pacific Fleet by surprise. Despite initial warnings, American defenses were unprepared, with many aircraft parked closely together and guns unmanned. The attack led to significant losses for the United States, including the sinking of several battleships and the destruction of many aircraft. The Japanese lost fewer planes but faced increasing resistance from American anti-aircraft fire by the second wave. The decision not to launch a third wave to target shore facilities was later seen as a missed opportunity, as destroying these could have significantly delayed American operations in the Pacific.

Ships lost or damaged

Further information: List of United States Navy ships present at Pearl Harbor, December 7, 1941

Twenty-one American ships were damaged or lost during the attack on Pearl Harbor. Most of these ships were repaired and returned to service later. Five battleships, after being fixed, even took part in an important battle that helped the United States win against Japan.

Battleships

• Arizona: hit by bombs, exploded, and could not be saved.
• Oklahoma: hit by torpedoes, turned over, and could not be saved.
• West Virginia: sunk but was fixed and returned to service in 1944.
• California: sunk but was fixed and returned to service in 1944.
• Nevada: damaged but was fixed and returned to service in 1942.
• Pennsylvania: damaged while in a dry dock but stayed in service.
• Tennessee: damaged but returned to service in 1942.
• Maryland: damaged but returned to service in 1942.

Ex-battleship (target/AA training ship)

• Utah: hit by torpedoes, turned over, and could not be saved.

Cruisers

• Helena: hit by a torpedo but returned to service in 1942.
• Raleigh: hit by a torpedo but returned to service in 1942.
• Honolulu: had light damage but stayed in service.

Destroyers

• Cassin: damaged in a dry dock but was fixed and returned to service in 1944.
• Downes: damaged in a dry dock but was fixed and returned to service in 1943.
• Helm: damaged but kept patrolling and returned to service in 1942.
• Shaw: hit by bombs but returned to service in 1942.

Auxiliaries

• Oglala: damaged and turned over but returned to service in 1944.
• Vestal: damaged but returned to service by 1942.
• Curtiss: damaged but returned to service in 1942.
• Sotoyomo: damaged and sunk but returned to service in 1942.
• YFD-2: damaged and sunk but returned to service in 1942.

Salvage

Captain Homer N. Wallin led a formal salvage operation to recover ships after the attack. Divers worked on damaged ships, patching holes and pumping out water. Within six months, five battleships and two cruisers were fixed enough to move for more repairs.

Salvage work continued for another year. The ships Arizona and Utah were too damaged to save and stayed where they sank. The Oklahoma was raised but later capsized while being towed. The Nevada was hard to repair, and some workers got sick from gases inside the ship. Parts from damaged ships were used to strengthen defenses in the harbor.

News coverage

Coverage in the United States

When the attack on Pearl Harbor began, the White House Press Secretary, Stephen Early, announced that Japan had attacked Pearl Harbor and other military sites on the island of Oahu. News programs on radio stations like CBS and NBC quickly shared the news with listeners, interrupting regular shows to report what was happening.

Only a few thousand television sets existed at the time, and most were in cities like New York, Chicago, Los Angeles, and Philadelphia. The attack was shown on a few TV stations, but no recordings of these broadcasts survive today.

Coverage in Japan

In Japan, news of the attack was announced on the radio in the morning, stating that Japan was now at war with the United States and Britain. Newspapers in Japan reported the attack, but the government controlled what was reported. One major newspaper, The Asahi Shimbun, shared the news and supported the government’s decisions.

Coverage elsewhere

The British Broadcasting Corporation (BBC) in the United Kingdom reported the attack and also mentioned that Manila in the Philippines was also under attack.

Aftermath

Main articles: Consequences of the attack on Pearl Harbor and Day of Infamy speech

The day after the attack, U.S. President Franklin D. Roosevelt gave a famous speech to Congress, asking for a declaration of war on Japan. Congress agreed quickly. Soon after, Germany and Italy also declared war on the United States.

The attack surprised many Allied nations. Japan attacked the Philippines soon after, and other battles followed. The event changed the course of World War II, drawing the United States into the conflict.

The attack had lasting effects, including changes in military strategy and the treatment of Japanese Americans, who were often treated with suspicion and sometimes relocated to special camps during the war. Many military honors were awarded to those who showed bravery during the attack.