How (Almost) Everyone Failed to Prepare for Pearl Harbor

UNITED STATES

The attack on Pearl Harbor, 75 years ago this week, was the worst day in the U.S. Navy’s history and the shock of a lifetime for just about any American who had achieved the age of memory. Why was the attack a surprise to almost everyone—including the Japanese? (Smithsonian)

Use our great interactive timeline to better understand the Pacific Theatre of World War II, and our article to understand the attack on Pearl Harbor itself.

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

It took two weeks for the Japanese fleet to reach Pearl Harbor, and another two to return to Japan. Map by U.S. Army, courtesy Wikimedia. Public domain

It took two weeks for the Japanese fleet to reach Pearl Harbor, and another two to return to Japan.
Map by U.S. Army, courtesy Wikimedia. Public domain

“When a bomb blasted the Arizona's forward magazine, the ship disappeared in a thousand-foot mountain of boiling, bluish-purple smoke.” The ship burned for two days, and 1,177 crew members were killed. It remains the greatest loss of life on any warship in American history. Photograph courtesy the National Park Service, The USS Arizona Memorial Photo Collection

“When a bomb blasted the Arizona’s forward magazine, the ship disappeared in a thousand-foot mountain of boiling, bluish-purple smoke.” The ship burned for two days, and 1,177 crew members were killed. It remains the greatest loss of life on any warship in American history.
Photograph courtesy the National Park Service, The USS Arizona Memorial Photo Collection

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.

 

pearl harbor map

Click to learn a little about the major targets of the “date which shall live in infamy.”

 

  • What risks did the Japanese take in launching such an audacious attack? What were their vulnerabilities?
    • Leaks. The Japanese could easily lose the crucial element of surprise. Allied intelligence was eavesdropping on Japanese radio, and there were leaks from within the Imperial Navy itself.
    • Weather. The open water of the North Pacific can be tempestuous in late autumn and early winter. Even today, storms drive winds and waves to sink ships.
    • New technology. No military had used aircraft carriers to the extent that the Japanese did at Pearl Harbor, and many strategists wondered if the fleet could manage the difficult tanker-to-warship refueling needed to get the fleet to battle and back.
    • US Navy. The Pacific Fleet could have been conducting maneuvers or exercises outside the harbor, and even well away from the island itself.
    • Most importantly, geography. The Pacific Ocean is BIG. The secret Japanese attack force was in transit for two weeks, vulnerable to detection or even attacks. The US had planes and submarines patrolling the Pacific from the Aleutian Islands in Alaska to Hawaii and Midway, and as far south as the Philippines.

 

  • 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.”

 

TEACHERS TOOLKIT

Smithsonian: How (Almost) Everyone Failed to Prepare for Pearl Harbor

Nat Geo: Date Which Will Live in Infamy article

Nat Geo: World War II in the Pacific timeline

Nat Geo: What were the targets on the “date which shall live in infamy”? MapMaker Interactive map

Nat Geo: Remembering Pearl Harbor interactive

Nat Geo: Use This Interactive to Remember the Tragedy at Pearl Harbor study guide

Nat Geo: Meet Ranger Martinez, the Chief Historian at Pearl Harbor article

One response to “How (Almost) Everyone Failed to Prepare for Pearl Harbor

  1. Pingback: Weekly Warm Up: Use This Attack Map to Remember the Tragedy at Pearl Harbor | Nat Geo Education Blog·

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