Japanese Attack On Pearl Harbor

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The following essay is intended to investigate whether or not the Japaneseattack on Pearl Harbor in 1941 could have been avoided, and whether or not the American government had any prior awareness of the forthcoming invasion. The essay will utilize a close examination of the American Intelligence System at the time of the attack as well as the activities of specific American individuals in order to analyze why the United States had been so unprepared for the assault. As well as providing some original ones, this essay also supports or refutes a number of pre-existing theories of how America came to suffer such a tragedy. In the end, this essay ultimately closes with the theory that the incompetence of the American Intelligence System, the underestimation of the Japanese, and the faults made by the American individuals at both the higher and lower end of the chain of command were the primary factors that led America to fail in avoiding the Pearl Harbor attack.

Sunday December 7th, 1941, a day that President Franklin Roosevelt stated would forever “live in infamy”, changed American history. On the morning of this very day, the American Sea Fleet stationed in Pearl Harbor was bombed by a Japanese air force and undertook devastating damage; eight battle ships were virtually destroyed, eleven hundred American soldiers were injured, and over two thousand were killed in the attack (Kinley 22). The consequences did not end there, as well as the many lives and armaments lost, the attack also became the trigger that pushed America into the second World War. Though it has been over 60 years since the attack and Japanese-American relations are in good tact today, the attack on Pearl Harbor still lives in the hearts of many and is widely recognized as one of the most significant military tragedies of American history (Murray 231). The level of devastation of this attack often leads to many questions. How could the American fleet stationed at Pearl Harbor have been so unsuspecting of such the attack? Did the American government have any prior awareness of this catastrophe? And most importantly, could this notorious event have been avoided?

Questions such as these arose since the day of the attack, and numerous historians and analysts have come to various conclusions. Despite the number of years that have passed since the attack, one of the few facts that have come to be solid is the level of intelligence the American government had prior to the actual attack. However, in order to conclude whether or not the attack could have been prevented, a deeper assessment must be made. The answer does not lie within the faults of a specific person or faction, but instead a wide range of sources, such as the incompetence of the American intelligence system, the unexpected strength of the Japanese, and the faults made by the United States military and navy from both the higher and lower end of the chain of command.

Many were shaken by the Japanese attack on Pearl Harbor because no one expected such a tragedy to occur when the Japanese and Americans were frequently in negotiations. However, the Pearl Harbor bombing should not have come to have been a major surprise due to the information that was available to the U.S. government prior to the attack. Since the 1920’s, the U.S. government had been working on a project to intercept and decode secret Japanese messages. This project, known as “Project Magic” (Rogers 12), of cryptoanalysis consisted of three divisions of Japanese codes: the Red, Purple, and JN 25 code. In early 1924, America’s Signal Communication Intelligence intercepted and decoded the Red code. America had often used this code in order to benefit itself in its negotiations with Japan (Dingman 80). Almost after the Red code was cracked, the Signal Communication Intelligence intercepted the JN 25. This code was a major discovery; it contained Japanese military data, including specific plans on the invasion of Pearl Harbor (Kahn 56). However, the JN 25 code was not completely decoded until after the attack on Pearl Harbor, mainly because of the fact that the U.S. believed that the last code, Purple, was the most important (Rogers 12). It was discovered that code Purple was used to carry Japan’s most crucial information and was considered its most guarded system of communication. Even though America did not decipher all of the information that was encoded in the Magic Project, the data gathered was enough to forewarn America of an imminent invasion (Dingman 89). Along with the Red, Purple, and JN 25 code, the Winds Code was also intercepted towards the fall of 1941 and proved to be another significant piece of information reinforcing the idea that an imminent Japanese attack was certainly a possibility (Kahn 51). After decoding the information, American Intelligence found that the Japanese capital was sending covert messages ordering all Japanese diplomats to prepare for an emergency situation in which they would sever all international communication and stop using the Code Purple contact lines (United States Government). In other words, it became evident that the Japanese planned on using the Winds Code as a means of auxiliary communication for clandestine operations when the two countries would finally be at war. Furthermore, America managed to intercept another set of ciphers during the winter of 1941 and decode it to find a message sent out by the foreign minister of Japan. The message stated that it was a high priority for the Japanese to make it seem as if the possibility of the two nations going to war was very slim by continuing their negotiations despite the fact that war between the East and West was most definitely at hand (United States Government). Through the Magic project, America continued to intercept more clandestine Japanese messages that warned America of a pending attack. For instance, on the December of 1941, the United States Intelligence managed to come upon a covert message seeking Japanese officials in Hawaii to forward the locations of United States battleships in Pearl Harbor twice a week (Kahn 99). Japan’s request for a more thorough report on the whereabouts of American ships and carriers again indicate that an attack on Pearl Harbor was certainly a likely possibility. Shortly after, the government intercepted an infamous message: “The Japanese Government regrets to have to notify […] that in view of the attitude of the United States Government […] that it is impossible to reach an agreement through further negotiations” (United States Government). On December 7, the U.S. intercepted its final and perhaps most astounding message of the Magic project. The intercepted message ordered the embassy in Washington to rid the remaining of secret files and the machines used to dispatch the clandestine Japanese messages. The American intelligence was aware of the abnormal behavior of the Japanese ambassador and its diplomats and this final message raised American suspicions (Baldwin 542). Along with the signs of an imminent Japanese invasion, the American government was also able to witness signs of the powerful capabilities of the Japanese military. When the Japanese invaded China in the late 1930’s, America got its firsthand observation of Japan’s dominant air force and navy (Seamon 74). During the summer of 1940, a United States investigator stated that the Japanese were in possession of a powerful 26-inched torpedo, known as the Model 97 torpedo, with the ability to fire at any sea vessel in a 25-mile perimeter at 40 knots. This armament was far more advanced than the 22-inched American torpedoes, which could only fire within a 5,000-yard perimeter at 40 knots (Seamon 95). Hence, is becomes evident how American government truly did have prior intelligence of a potential imminent Japanese invasion. Despite the fact that America was not able to decode all of the messages intercepted in Project Magic in time and consequently not discover the details of the attack, American government had a sufficient amount of valid information and data to realize that a Japanese attack was around the corner, that the offensive on Pearl Harbor was likely, and that Japan’s forces indefinitely had the potential to initiate an airborne offensive on Oahu (Rogers 15). Moreover, this undoubtedly proves false the belief that there just was not sufficient data to foresee a Japanese invasion of Pearl Harbor. Nonetheless, if the United States had enough information before the actual attack, why had the American forces at Pearl Harbor been so unwary of an attack? The cause of this is due to multiple reasons.

The ineffectiveness of the U.S. Intelligence system was partly responsible for the oncoming of the Pearl Harbor catastrophe. While the Intelligence system had plenty of information that ranged from in a broad spectrum, it was very uncoordinated due to the fact that Army’s Intelligence System and the Naval Intelligence Office constantly sought to outdo each other (Seamon 85). This intra-American struggle resulted in an ineffective system of intelligence as a whole (Absher 22). Realizing the inefficiency of their quarrel, the two associations eventually did come to an agreement to share all information they obtained. Unfortunately, the new system they used to handle information was just as ineffective, if not more. On the November of 1940, the Army’s Intelligence System and the Naval Intelligence Office decided the two would take turns every other month to provide any new information obtained from Project magic to the White house (Dingman 67). In spite of this, the Army’s Intelligence System believed that Washington would not provide enough security for the top-secret information and ceased to provide the White House with information from Project Magic. With the United States president lacking access to significant information from the Magic project, it is hard to believe that he could do a competent job of preventing the attack on Pearl Harbor, that is if he had even had the chance to know about it. This further illustrates the fact that the incompetence of the American Intelligence system at the time was indeed partly responsible for the oncoming of the Japanese attack on Pearl Harbor. Although President Roosevelt was once again able to gain access to Project Magic during the fall of 1941, he distrusted the army’s ability to provide him with information and gave the full responsibility to the Naval Intelligence Office (Murray 222). Unfortunately, the American’s intelligence as a whole ran into more trouble due to this change; President Roosevelt’s favoring of the Navy over the Army paired with the competition between the two organizations lead to the Naval Intelligence Office to hoard the most vital information of the Magic Project and to only dispatch it to the Army’s Intelligence System whenever it desired to do so. Overall, it becomes evident that if the American intelligence system was more centralized as a whole, the Pearl Harbor attack could have been more easily foreseen and perhaps even prevented (Dingman 71). The unnecessary quarrel between American Navy and Army prevented the establishment of a centralized and more well-organized Intelligence system. Had this cooperative system run more efficiently, it may have been enough to deter the invasion of Pearl Harbor.

The prejudicial attitude of the United States was also a catalyst for its incompetent use of American intelligence concerning the Pearl Harbor attack. When a report that the Japanese had performed an aerial offensive had reached American quarters, it was faced with skepticism and the military skills of the East were highly underestimated. America was blinded by its racial prejudice and believed that the eastern nations was still technologically inferior to West (Seamon 85). This misconception is evident by the fact that the Japanese were constantly portrayed in American media as having poor vision, being technologically uncoordinated, and both physically and mentally incompetent. The seriousness of the Japanese threat continued to be disregarded despite the continuing reports describing the exponential progress of Japan’s military technology and skill. For instance, reports, such as the one describing Model 97 torpedo, that were dispatched to the Naval Intelligence Office, were met with assertions that “there was no possible way a torpedo would propel at such a speed in such as range” (Seamon 95). Hence, the United State’s prejudice towards the East led it take the Japanese military power too lightly, which further lead America to not foresee the attack on Pearl Harbor.

When the attack on Pearl Harbor is discussed, the question “who’s fault was it” often arises. Two names that are most often mentioned are Lieutenant General Walter Short, the Hawaiian Army Department’s commander, and Admiral Husband Kimmel, the U.S. Pacific Fleet’s commander. These two men occupied two of the most critical positions when the Japanese struck Pearl Harbor (Rogers 22). Numerous conjectures claim that these two were responsible for the Pearl Harbor disaster. However, though it might seem absurd to blame the tragedy solely on these two men, they did make some serious faults that contributed to the forthcoming of the invasion. Short made several errors in his position. Despite how it was his obligation to protect Pearl Harbor, he did not notify his men of a possible Japanese assault. Additionally, it was part of his orders to perform a recon scouting around the area in order to anticipate an unexpected Japanese attack. Had he proceeded to do so, he may have been able to succeed in protecting Pearl Harbor despite his crew’s unawareness (Kahn 94). Admiral Husband Kimmel made his greatest error when he failed to dispatch, perhaps purposely, critical information to Walter Short (Dingman 285). On the third of December 1941, Kimmel received a message stating that the Japanese were dismantling their cipher devices and severing all communications, another indication that the time of negotiations between America and Japan was coming to an end. Despite how it was Kimmel’s job to forward this information to Short, he was not successful in doing so (Absher 24). If Kimmel had done his job and successfully forwarded to Short the information from Washington, Short may taken his duty to protect Pearl Harbor more seriously and prepare his forces for the imminent Japanese threat. There have been many debates on whom of the two was more responsible. However, United States government frequently informed both Short and Kimmel prior to the attack that the Japanese-American relations were on the verge of breaking down and that the Japanese were making breakthrough developments to prepare for the war (Seamon 94). For instance, on the night of November 25 1941, both Short and Kimmel received message stating, “This is a caution of war. […] The negotiations between America and Japan have ceased and an aggressive action by the Japanese is to be expected in the following days” and directed the men to, “deploy whatever necessary defense measures are needed” (United States Government). However, it is clear that Short and Kimmel did not heed the warning (Murray 326). Short and Kimmel also failed to take action when they received a dispatch stating that the Japanese diplomats in Honolulu were getting rid of all of their documents. Short later even testified that he believed the message “was not an important matter” (Baldwin 746). Furthermore, Kimmel received a dispatch an hour before the actual Japanese attack on Pearl Harbor stating that his men had destroyed a Japanese vessel attempting to infiltrate the area. Instead of taking preparatory action, Kimmel once again overlooked the notification (Garry 39). From these events, it is clear that Short and Kimmel failed to take seriously all of the evident signs of an imminent attack. Though some may find it understandable to overlook certain details in the chaotic time of a global war, Short and Kimmel should have looked more into these alerting notices due to the fact that they occupied some of the most critical positions of the nation’s defense (Rogers 25). Additionally, their actions cannot be exempted due to the fact that they lacked adequate information; for it is quite evident from the previously mentioned cases that they received plenty of messages and dispatches prior to the attack that would have served sufficiently in warning them of an imminent attack. Thus, it is clear that Walter Short and Husband Kimmel failed to perform their duties in spite of how they had access to documents and messages indicating an imminent attack. Had Short and Kimmel taken the dispatches more seriously, the outcome of the Japanese invasion of Pearl Harbor may have turned out dramatically different.

In addition to Short and Kimmel, George Marshall, the general of the Army Chief of Staff, and Harold Stark, the Naval Operation’s admiral, were also partly responsible for the level of severity that Pearl Harbor underwent (Rogers 14). Many theorists claim that Marshall and Stark’s failure to forward dispatches to Kimmel and Short were done intentionally as if the two had been part of a conspiracy to push America into the World War (Mueller 274). To support this hypothesis, these theorists often state how on the morning of the attack, Stark had failed to immediately forward a critical section of an emergency dispatch to Kimmel (Mueller 265). However, what is often overlooked is that Stark was “hesitative to dispatch more” alerts because he believed that Short and Kimmel had already been “sent a numerous amount messages” (United States Government). Unfortunately, despite how investigations proved that dispatches were indeed sent, they were received after the Japanese assault had already occurred (Kahn 140). Though it is true that dispatches could have made it in time if Stark and Marshall had not been so hesitative, there is not enough proof to confirm that the two were part in a scheme to push America into war. However, it cannot be denied that, in addition to their failure to forward the dispatches in time, Stark and Marshall were also partly responsible for the lack of readiness for a Japanese invasion at Pearl Harbor. Marshall even proceeded to state in public that he was partly to blame for the attack on Pearl Harbor due to the fact that he did not understand the incompetence of Short’s response to the alert on November 28 and to amend it (Absher 22). He proceeded to state, “This was my chance to get involved. […] But I failed to do so” (United States Congress). Furthermore, Marshall and Stark, as Short and Kimmel had done, failed to see that Pearl Harbor was a very plausible area for the Japanese to strike (Dingman 245). From investigating the top positions of the American army and navy at the time of the Japanese assault on Pearl Harbor, it becomes clear that the severity of the attack and why it was not prevented lies in the incompetence of some of America’s military leaders. Despite how it cannot be denied that Short and Kimmel were fundamentally accountable for the tragedy of the Pearl Harbor attack, Lieutenant General George Marshall and Admiral Harold Stark, the commanders of the whole American military, are also certainly responsible.

At the time of the Japanese assault on Pearl Harbor, Franklin D. Roosevelt, as President of the United States, occupied the role of the leading figurehead. However because he occupied such a high position, the Commander in Chief has often been accused as being a conspirator, purposely not dispatching critical information to his men in Pearl Harbor to allow the Japanese invasion to occur in order to keep his private pledges with England to join the war while maintaining the support of the American citizens (Mueller 184). Despite these claims, the evidence given to support these accusations does not prove itself to be very legitimate. Had the president actually desired the troops at Pearl Harbor to be hit by an unexpected attack to push America into the war, he could have merely alerted them at the last second in order to achieve this goal. On the other hand, Roosevelt actually dispatched several warnings multiple times (Dingman 116). As observed earlier, it was largely due to the lack of action from Admiral Husband Kimmel and Lieutenant General Walter Short that Pearl Harbor was struck so unexpectedly and severely. Moreover, had the troops at Pearl Harbor have managed to pull off a successful defense from the surprise Japanese attack, America would still have gone to war and President Roosevelt’s reputation would have benefited from the success (Garry 34). As for the accusations claiming that the president had ulterior aims to assist England, one should not ignore how Roosevelt disregarded Winston Churchill’s call for assistance on several occasions, declaring that he had “no sense intended to commit and did not commit the [American] Government to military participation in support of the Allied Governments” (Drea 274). Furthermore, the President maintained a war in the Pacific would divert their attention from the true adversary of the global conflict, Germany (Murray 385). As a result, he avoided a war with the Japanese. Despite how his efforts eventually failed, Roosevelt repeatedly sought to negotiate with the Japanese through actions such as economic agreements and requesting for peace with the Japanese Emperor in December 1941 (Absher 19). From the given evidence, it is clear that President Theodore was not part of a conspiracy intending to allow the bombing of Pearl Harbor. However, this does not imply that Roosevelt was blameless for the Pearl Harbor attack; as we saw earlier, his tendency to prefer the Navy over the Army lead to the incompetence of American Intelligence System(Dingman 285). Additionally, Roosevelt, like many others, did not suspect that a Japanese attack was not imminent despite the indications of tension between America and Japan. For instance, Roosevelt delayed the dispatching of a critical message to the naval commanders a whole day to attend a meeting (Kahn 99). As a result, it is clear the President Theodore Roosevelt, as President of the United States, could have carried out his obligations more responsibly and effectively to avert the attack on Pearl Harbor.

Along with the errors made by the high-seated officers in American forces, people in the lower chain of command also made errors that contributed to America’s lack of preparedness for the Pearl Harbor invasion. In both the navy and the army, duties were not performed efficiently, resulting in the Japanese invasion. For instance, on the sixth of December 1941, Carlisle Clyde Dusenbury, Colonel of the Eastern Sector of the G2 army for Washington, received a critical alert message from Project Magic to be delivered to George Marshall. However, instead of dispatching the message as soon as possible, the colonel decided to spend the rest of the night at home and delayed the transmission by nine hours (Dingman 211). Had Dusenbury immediately sent the dispatch, which stated that the diplomacy between America and Japan were ending, the American forces at Pearl Harbor may have been alerted and able to deter the Japanese assault. Another officer that made some significant blunders is Lieutenant Colonel George Bicknell. During his station, Bicknell witnessed multiple forewarnings from Washington that the all of the Japanese diplomats were destroying the code systems, yet failed to alert Kimmel. As a result, Kimmel became aware of these warnings in a meeting several days later and, like Dusenbury, lost American forces in Pearl Harbor valuable time to prepare for the invasion (Warren 36). Along with Dusenbury and Bicknell, Kennet Tyler, Lieutenant of the same division, received a report from radar operatives stating that an oddly large air fleet, which were actually the Japanese invaders, heading toward their direction. Tyler, however, presumed that this fleet was a group of American air vessels flying in from the motherland and, once again, the troops at Pearl Harbor lost a chance to set up a sufficient defense again the invaders (Murray 395). Hence, it is evident that several mistakes were made also by the operatives in the lower end of the chain of command and contributed to the severity of the Pearl Harbor invasion. Had they performed their duties more efficiently, the Pearl Harbor attack may have not ended so gravely for America.

By examining the given evidence found through a thorough investigation of what really took place at the time of the Pearl Harbor attack, it becomes quite evident just how much the American government was aware of the invasion and whether or not the attack could have been avoided. One should recognize the significance of how this issue has been the basis of many debates and, thus, political partiality and personal disposition may bias the tone of a source. As a result, direct records have been used to guarantee a fair, objective conclusion. Hence, it is conceivable to conclude that the U.S. government, largely through the usage of Project Magic, was capable of recognizing that a potentially destructive attack on Pearl Harbor by Japan was imminent and alerting the fleet at Pearl Harbor in time to set up a sufficient defense. On the other hand, the incompetent system of intelligence, prejudicial attitude towards the Japanese, and errors made by officers at both the higher and lower end of the chain of command altogether cumulated into America’s inability to avoid the Japanese invasion of Pearl Harbor.


Primary Sources

United States Congress. Joint Committee Investigation of the Pearl Harbor Attack. 13 Dec. 1941. Print.

United States Government. Report of Army Pearl Harbor Board. 20 Jan. 1944.

United States Government. Hearings Before the Joint Committee on the investigation of the Pearl Harbor Attack. 19 Oct. 1944.

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Baldwin, Hanson. America at War: Three Bad Months. New York: Foreign Affairs, 1991.

Dingman, Roger. Pearl Harbor Revisited. 3rd ed. Vol. 83. Bloomington: The Journal of American History, 1996.

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Garry, Clifford. Pearl Harbor Revisited. Chicago: The Journal of American - East Asian Relations, 1996.

Kahn, David. The Intelligence Failure of Pearl Harbor. Foreign Affairs. History Today. 1992.

Kinley. "Pearl Harbor Casualty List Reported." The Casper Tribune Herald [Casper] 9 Dec. 1941.

Mueller, John. Pearl Harbor: Military Inconvenience, Political Disaster. Vol. 16. Ser. 2. Cambridge: International Security, 1991.

Murray, Ann Y. A Date Which Will Live: Pearl Harbor in American Memory. 4th ed. Vol. 63. Ann Arbor: Journal of American, 1999.

Rogers, Michael. Pearl Harbor: Japan's Fatal Blunder. Hippocrene 1 Feb. 2004. Print.

Seamon, Richard. Defenseless: Command Failure at Pearl Harbor. 4th ed. Vol. 130. Annapolis: United States Naval Institute Proceeding, 2004.