Intelligence Failure


There are many questions about what exactly caused the disaster that occurred at Pearl Harbor on December 7, 1941. By December 8, the questions as to who made what mistake and who failed to do what were being asked. After more than sixty years and dozens of books, the questions are still being asked. The result of this great mistake is simple to define. The U.S. fleet and U.S. Army air corps airfields were not ready for the attack. They were set up in such a way as to be almost as vulnerable as possible. Unless a lot of people wanted to see the U.S. Pacific fleet slaughtered, and they did not, a mistake occurred that ceded control of the Pacific for months.

The commanding officer of the Pacific fleet was Admiral Kimmel, and General Short commanded the army air bases. The air force was not yet a separate branch of the armed services. On Sunday, December 7, 1941, as the map shows (see page 291), the Japanese struck both the fleet in harbor and the air bases. The attack totally surprised everyone in Hawaii. In many cases, only skeleton crews manned the ships and ammunition for antiaircraft guns was locked away. That did not need to have happened. Someone made a very great mistake that affected the entire war in the Pacific. The failures were there, but not the ones most people expect.

To begin with, let’s eliminate any thought that there had not been sufficient warning. Three communications sent days earlier pretty much ruled that out. While Pearl Harbor was not directly threatened, the tone of the communications showed that war was close and inevitable. The only question was where it would start. Read them for yourself:


This dispatch is to be considered a war warning. Negotiations with Japan looking toward stabilization of conditions in the Pacific have ceased and an aggressive move by Japan is expected within the next few days. The number and equipment of Japanese troops and the organization of the naval task forces indicates an amphibious expedition against either the Philippines, Thai or Kra Peninsula or possibly Borneo. Execute an appropriate defensive deployment preparatory to carrying out the tasks assigned in WPL 46 [the navy’s war plan]. Inform district and army authorities. A similar warning is being sent by the War Department.

In 1941, the air force was a part of the U.S. Army.


Negotiations with Japan appear to be terminated to all practical purposes, with only the barest possibilities that the Japanese Government might come back and offer to continue. Japanese future action unpredictable, but hostile action possible at any moment. If hostilities cannot, repeat cannot, be avoided, the United States desires that Japan commit the first overt act. This policy should not, repeat not, be construed as restricting you to a course of action that might jeopardize your defense. Prior to hostile Japanese action you are directed to undertake such reconnaissance and other measures as you deem necessary, but these measures should be carried out so as not, repeat not, to alarm civil population or disclose intent. Report measures taken. Should hostilities occur, you will carry out the tasks assigned to Rainbow Five [the army’s war plan] so far as they pertain to Japan. Limit dissemination of this highly secret information to minimum essential officers.


Highly reliable information has been received that categoric and urgent instructions were sent yesterday to Japanese diplomatic and consular posts at Hong Kong, Singapore, Batavia, Manila, Washington and London to destroy most of their codes and ciphers at once and to burn . . . confidential and secret documents.

So four days before the Japanese attack on Pearl Harbor, both commanders knew that the Japanese diplomats were preparing for war. The only surprise was that the attack came at Hawaii.

If you had commanded the only U.S. Navy fleet in the Pacific or the main Pacific air base, what action would you have taken? Admiral Kimmel and General Short decided that, even with war imminent, there was no concern for an attack on Pearl Harbor since the various intelligence branches had not specifically mentioned one but did see signs of other attacks (which also happened). So on the basis of this, and perhaps personal and racial egotism, they did nothing to prepare for such an attack. The island was not even on alert, and crews were allowed to leave all the docked ships. Obviously Kimmel did not see his fleet as being at risk.

This mistake becomes even less understandable when you realize that less than a year earlier, obsolete British aircraft attacked and sunk a good part of the Italian fleet while docked in the similarly shallow and protected Taranto harbor. Or that by November 16, the bulk of the Japanese fleet and all its major carriers had simply disappeared. The United States had no idea where the main fleet was of a nation it knew was preparing to attack them. Yet the commanding officers in Hawaii had their bases in a very low level of alert.

This attitude, and the low alert level, led to more minor mistakes that made things worse. When the new radar unit spotted the approaching first wave of attackers, the operator told his commander, and the officer commanding the radar station assumed it was six army bombers that were expected that morning. Ships radioed warnings when the Japanese flew overhead, but these were still being processed in a lightly manned communications center when it was too late. Reports of periscopes also failed to bring the bases to a higher level of alert. Despite the situation, the sightings, and the unknown location of the Japanese carrier fleet, from the commanding officers on down, nothing was done in time to stave off disaster.

Actually nothing is not correct: Both American commanders had taken some recent actions. They were, however, very bad decisions that made the situation worse. Based in Pearl Harbor were eight battleships, three aircraft carriers, and numerous supporting ships. Even docked, if on full alert and warned, this was a powerful antiaircraft defensive force. Unfortunately, the fleet was at a very low level of alert, which meant that on a Sunday morning most of the crew was ashore. When the Japanese attacked, there were not even enough sailors to man all of the guns. Those who were on the ships in the harbor woke to explosions and sirens. Many never made it to the deck or their stations before their battleships were sunk. Even unprepared, the navy and army defenders shot down twenty-nine planes from the two waves of more than 350 attacking.

The army air force was equally badly prepared. The few men on the base were surprised at breakfast. Ammunition lockers were locked, and when the first wave attacked, barely a quarter of its machine guns, and only four of thirty-one antiaircraft batteries, were fired. General Short had been much more concerned about sabotage by spies hiding among Hawaii’s large Japanese population than about the chance his air bases would be bombed. As a result, he ordered all of the aircraft to be lined up in straight rows in the open on the runways. This way they all were far from the fences, and it allowed the MPs to keep a good eye on them. This setup also made them perfect targets for bombing and strafing attacks. The Japanese attackers simply flew along the tightly packed lines of American aircraft and were able to destroy several planes with each pass. Virtually none of the army aircraft made it into the air, not even an hour later when the second attack wave hit.


The attacks on Pearl Harbor

When the second wave had finished, five battleships and two destroyers were sunk or so badly damaged that they couldn’t be used for the rest of the war. Four more battleships and five cruisers were damaged. The army air corps lost almost 200 of 350 planes with most of the rest damaged. More than 2,400 veteran sailors, marines, and soldiers died. Only the coincidence that all three U.S. carriers were at sea prevented total disaster.

The mistake made by Admiral Kimmel and General Short was not to be prepared. Another was to ignore the intelligence they had been given. If the American Pacific surface fleet had not been effectively neutralized on December 7, 1941, then the Japanese expansion and successes in 1942 might well have been much less. The Philippine Islands might have been successfully reinforced, and so no Bataan Death March. But the mistake was made, and for the next year, the Japanese expanded without real resistance until they occupied much of the Pacific Ocean and were threatening Australia itself. These two commanders, who resigned on December 8, had the most important American bases in the Pacific on low alert. With war expected any moment, it was a mistake that cost thousands of lives and changed the nature of the war in the Pacific. There certainly was an intelligence failure, and it was the intelligence of those who had been in command.

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