How (Almost) Everyone Failed to Prepare for Pearl Harbor

UNITED STATES

Teachers, scroll down for our great collection of resources on Pearl Harbor, including today’s MapMaker Interactive map.

Discussion Ideas

Take a look through our timeline of World War II in the Pacific. What major aggressive actions had Japan taken before its attack on Pearl Harbor?
- 1931: Japan invaded and occupied China (Manchuria) and set up a puppet government there.
- 1936: Japan entered into the Anti-Comintern Pact with Nazi Germany, and, later, Fascist Italy. These nations led the Axis Powers.
- 1940: Japan invaded and occupied Indochina, a region that includes all or parts of the nations of Vietnam, Cambodia, Laos, and China.

What were American responses to these acts of aggression?
- The US engaged in economic sanctions, including cutting off all exports of oil to Japan. This hit the island nation hard, as the US was its chief supplier of this vital fuel.
- The US provided food, oil, and supplies to resistance movements in China and Indochina through the Lend-Lease Act.
- The US froze all Axis funds in American financial institutions, meaning Japan could not access and spend money held in American banks.

Admiral Isoroku Yamamoto, the architect of the Pearl Harbor invasion, initially opposed war with the United States. Why?
- The US is much bigger, with a lot more resources, and Yamamoto knew it.
  - “During two tours in the United States, in 1919 and 1926, he had traveled the American continent and noted its energy, its abundance and the character of its people. The United States had more steel, more wheat, more oil, more factories, more shipyards, more of nearly everything than the Empire, confined as it was to rocky islands off the Asian mainland. In 1940, Japanese planners had calculated that the industrial capacity of the United States was 74 times greater, and that it had 500 times more oil.”
  - The US would likely recover from intense conflict, but Japan, unassisted, would not. “Japan’s resources will be depleted, battleships and weaponry will be damaged, replenishing materials will be impossible,” Yamamoto wrote.

If Yamamoto assessed the conflict so negatively, why did he insist on attacking the US so totally, so massively?
- He had to; an enormous surprise attack was the only hope Yamamoto had of Japanese success. “Japan, as the smaller power, must settle it ‘on its first day’ with a strike so breathtaking and brutal that American morale “goes down to such an extent that it cannot be recovered.”
- The strategy was a success. Daniel Martinez, chief historian at Pearl Harbor, says “It was a total surgical strike to knock out our airfields, which they did within 15 minutes, and then knock out the Pacific Fleet, which they did within 20 minutes.” Think about that.
  - Take a look at today’s MapMaker Interactive map of what the invasion targeted on Oahu.

What technology allowed the Japanese to engage in such a massive attack?
- Aircraft carriers. The Japanese “had brought six [aircraft] carriers. This was unprecedented in history. This was the first time that a naval force would use that amount of planes, 350 aircraft,” says Martinez.
  - “They still had battleships … but battleships and cruisers had to move to within sight of the enemy to sink him. Aircraft carriers could lurk 100, even 200, miles away, far beyond the range of any battleship gun, and send dive bombers and torpedo bombers to attack their unsuspecting adversary. And having a mass of carriers sail as one and launch simultaneously, rather than sail scattered or alone, dramatically enhanced their destructive power.”

How did the United States underestimate the Japanese military in general?
- Although the US sanctioned the Empire of Japan following its invasion of China, the real focus of foreign policy at the time was the war in Europe.
- The US was dismissive of Yamamoto and Japan’s military intelligence. The Smithsonian article notes American “complacency, anchored in two assumptions: that our Asian adversary lacked the military deftness and technological proficiency to pull off an attack so daring and so complicated, and that Japan knew and accepted that it would be futile to make war on a nation as powerful as the United States.”

How did United States intelligence miss the Japanese fleet aiming for Hawaii?
- The US Navy focused on the Japanese warships headed toward the Philippines, where authorities thought Japan would invade next. (It did.)
- The Pacific Fleet had received “alarming dispatches from Washington warning of Japanese aggression” for more than a year. The commander of the fleet, Admiral William Halsey, called these “wolf dispatches” because they had never amounted to anything.
- Local air patrols generally stuck pretty close to Oahu, and focused on finding rogue submarines.
- Even when US radar detected unusual activity on the radar on December 7, the privates who noted the anomaly were told to “forget about it.” The activity was so unusual, it was dismissed as a freakish blip on the radar screen instead of evidence of an advancing enemy fleet.

How was the US able to recover from the devastation and, ultimately, win the war?
- Yamamoto’s initial assessment of the situation was right: The US was big, faced no real threat to its home territory or population, and had huge reserves of human, natural, and industrial resources.
- “The military damage of the attack was far less than first imagined. Feverish repairs on the battleships commenced, in Hawaii and then on the West Coast.” Most battleships targeted at Pearl Harbor were repaired, rebuilt, or recommissioned. (Three—the Arizona, the Utah, and the Oklahoma—were total losses.) One ship damaged at Pearl Harbor, the West Virginia, was present in Tokyo Harbor four years later as the Empire of Japan unconditionally surrendered to American forces.
- The attack unified American sentiment to end the war on both fronts. “If you remove the emotion and look at it, the Japanese had achieved a great victory and success,” Martinez says. “But it was also the biggest public relations (PR) disaster any nation had done in the 20th century. In achieving that, they certainly outraged a nation and ensured their defeat.”