The famous twentieth-century American comedian Groucho Marx once said: “Military intelligence is a contradiction in terms.” While probably unintentional, this quote perfectly illustrates an essential paradox surrounding the field of (military) intelligence: although intelligence is often described as being about ‘reducing uncertainty’ for governments and decision-makers, it can also make matters more complicated due to its fragmentary, uncertain, and secretive nature. Indeed, within the military domain, the role of intelligence has famously been downplayed by none other than Carl von Clausewitz when writing about the Napoleonic Wars. He noted that intelligence was often inaccurate and not insightful enough to influence the battlefield situation, primarily determined by superior forces and firepower (Clausewitz, 1873, pp. 117 & 140). Yet, other influential strategists such as Sun Tzu have argued somewhat differently, often emphasizing that intelligence is essential in military operations.

Accordingly, this paper taps into this debate about the ambiguity surrounding the value of intelligence by considering the role of intelligence in the early stages of the Pacific Theater in the Second World War (WW2), specifically concerning the Battle of Midway (1942), to analyze how intelligence, and how decision-makers used it, helped with the preparation and management of the engagement. The paper will first briefly introduce the field of military intelligence before zooming in on the Pacific Theater of WW2, which proves to be an insightful case study when analyzing the value of intelligence in managing war and crises. In doing so, particular attention will be paid to the Battle of Midway while also taking the Attack on Pearl Harbor (1941) and the Battle of the Coral Sea (1942) into account. Finally, after considering the key takeaways from these analyses, the paper will end with a conclusion.  

(Military) Intelligence

Governments and decision-makers need accurate information and assessments to develop a national security policy, especially concerning the intentions and possible actions of foreign states and other actors (Chuter, 2011, p. 105). Such information can be collected through both open and secret sources. Still, in times of hostilities, the amount of required information that needs to be acquired by covert means often becomes emphasized. Accordingly, this paper follows David Chuter’s (2011) definition of intelligence as the process of acquiring and using information from an entity that does not want you to have that information and does not realize that you have received it. Yet, while decision-makers undeniably need the information to respond to events and prepare for future scenarios, especially in times of war, a lot of the intelligence produced has often proved unreliable and in such quantities that a mass of trivialities masks what really matters (Ferris, 2015, pp. 637–638). This can subsequently lead to fragmentation within the chain of command and between intelligence agencies and complicate decision-making.

As a result, throughout Western history, intelligence generally did not enjoy a prominent status within military affairs. For example, when Victorian historian Edward Creasy described the ‘fifteen decisive battles of the world,’ intelligence was only featured in one of the fifteen battles; the rest were determined by sheer strength and will (Kahn, 2006, p. 125). This was simply because intelligence capabilities were generally not developed enough to provide reliable information consistently. Yet, following the advent of signals intelligence in the late 19^th and early 20^th centuries, intelligence started gaining prominence as intelligence significantly contributed to battlefield victories. The introduction of the radio as a means of communication greatly impacted this development because it allowed armies to intercept messages communicated wirelessly over great distances (Kahn, 2006, pp. 129–131). Thus, after the First World War, all major powers took intelligence seriously, and intelligence became institutionalized everywhere. Interestingly, within this development, it was often a nation’s defeat that prompted the creation and development of an intelligence unit – if armies wanted to defend themselves against future attacks following a loss, they had to know or believe that one was coming (Kahn, 2006, pp. 126–129).

The use of signals intelligence, in combination with cryptoanalysis, became even more critical during WW2. Allied intelligence proved vital in reducing the uncertainty surrounding the German U-boat campaign, for example, and historians have even claimed that intelligence shortened the war by two years (Ferris, 2015, pp. 662–663). An important observation concerning the use of intelligence during WW2 is that many of the battles in which intelligence proved vital were defensive rather than offensive. Indeed, during the interbellum, the states that were not preparing for aggression mainly developed their intelligence capabilities, as opposed to the states preparing for war, which focused more on developing their offensive capabilities. As Clausewitz said, ‘awaiting the blow’ is the ‘characteristic feature’ of the defensive, and intelligence can therefore be a valuable tool in reducing the uncertainty of where that blow will be coming from (Kahn, 2006, p. 132).

Intelligence in the Early Pacific Theater

The early stages of the Pacific Theater of WW2 perfectly illustrate intelligence’s value in reducing uncertainty during crises and war. Yet, when thinking about this period, many will undoubtedly think about the notorious ‘intelligence disaster’ surrounding the failure of American intelligence to predict the Japanese Attack on Pearl Harbor in December 1940. In reality, however, American intelligence picked up several pieces of intelligence that pointed toward a Japanese attack on Pearl Harbor, but most of these warnings fell on deaf ears. These warnings included both pieces of intelligence that can be categorized as general and strategic warnings, derived from strategic-level communications systems in Washington, as well as several specific tactical warnings of potential hostile action surrounding Hawaii (Dahl, 2013, p. 74). The majority of the warnings can be considered strategic-level warnings, such as a letter prepared by Rear-Admiral Richmond K. Turner, the navy’s war plans chief in Washington, for the US Navy Secretary Frank Knox’s signature in January 1941, which was sent to Hawaii warning that: ‘If war eventuates with Japan, it is believed easily possible that hostilities would be initiated by a surprise attack upon the Fleet or the Naval Base at Pearl Harbor. (Prange et al., 1982, p. 45). More strategic warnings appeared in late 1941, such as sudden changes in the Japanese radio call signs in November and December, which further confirmed the already-existing notion that Japan was preparing for war against the US, an idea that had been augmented by America’s oil embargo on Japan (Dahl, 2013, pp. 73–77).

However, such strategic warnings provided limited predictive value for decision-makers because they were often too vague and general to help reduce specific uncertainties. Yet, there were also several specific tactical warnings, such as an intercepted message sent by the Japanese Foreign Ministry to its Honolulu consulate in October 1941 requesting detailed information on the warships anchored in Hawaii. A month later, a similar message was intercepted, which requested such reports twice a week from that point onward. Yet, the intelligence agencies in Washington never shared these messages with their military counterparts in Hawaii, as they considered a Japanese attack on Pearl Harbor unrealistic (Dahl, 2013, pp. 75–77; Wohlstetter & Schelling, 1962, pp. 211–213). Thus, despite the available warnings from intelligence sources, uncertainty remained due to the low receptivity of decision-makers toward the signs of a potential attack on Pearl Harbor. This low receptivity can be explained by (1) the fact that many officials did not deem the threat of an attack on Pearl Harbor as realistic and (2) a general lack of trust in intelligence, primarily due to the relative novelty of the intelligence methods of cryptography and traffic analysis, which were not yet trusted by senior decision-makers (Dahl, 2013, pp. 79–80; Parker, 2017, p. 2). Therefore, the failure to predict Pearl Harbor was not solely an intelligence failure but rather a failure to respond to the available intelligence adequately.

Following Pearl Harbor, the US had to regain its strength to counter the next Japanese offensive. Yet, while the Americans knew another offensive was coming, they did not know when or where they would strike. This was hugely problematic because the US was forced to wait and react to Japanese actions as they were fighting a defensive war and did not have the initiative. At the same time, Americans were also numerically inferior as well as outgunned, which meant that they had to concentrate their forces at the right place at the right time to have a realistic chance of success. As a result, the role of intelligence became critical (Schorreck, 1975). In early Spring 1942, intelligence sources indicated that the Japanese were planning an offensive toward Port Moresby, an Australian base in New Guinea. On April 29, based on the intelligence provided by the OP-20-G, Admiral Nimitz, Commander-in-Chief of the Pacific Fleet, ordered two carriers to the Coral Sea to engage the Japanese fleet. The ensuing Battle of the Coral Sea (1942) resulted in a tactical draw but a significant strategic setback for the Japanese (Dahl, 2013, pp. 82–83). But more importantly, it proved the value of signals intelligence to decision-makers, who were still skeptical about the relatively new methodology, especially following the failure to predict Pearl Harbor convincingly.

Battle of Midway: A Textbook Example

Following the Battle of the Coral Sea, American decision-makers faced heavy uncertainty again. Naval intelligence knew another campaign was being planned. The Japanese leadership, especially under Admiral Yamamoto, believed it had to rapidly conquer strategic footholds in the Pacific to destroy the Pacific Fleet and force the Americans to the negotiations table. Thus, once again, while it was evident that the Japanese were planning a new campaign, the objective was unknown, as well as the time of the attack and the composition of the enemy forces (Schorreck, 1975). As a result, intelligence became essential to prepare for the next Japanese attack, especially considering the damaged state of the American carriers returning from the Coral Sea. Intelligence, therefore, proved vital throughout the entire planning process surrounding the Battle of Midway in June 1942, both strategically and tactically.

By Spring 1942, the intelligence unit at Pearl Harbor (HYPO) assessed that the Japanese were planning major operations against a target designated as AF. Naval intelligence knew that the Japanese used such designators for geographic locations, such as RZP for Port Moresby and AH for Oahu. Based on the intercepted intelligence and because other Japanese ‘A’ designators all happened to be in the general vicinity of Hawaii, HYPO believed that AF was Midway Atoll (Schorreck, 1975). Yet, despite the previous success regarding the Coral Sea, Nimitz was not convinced by the intelligence provided. Instead, Nimitz made his own evaluation and regarded Oahu and even the West Coast as possible, believing that the Japanese could have also transmitted deceptive radio traffic. Moreover, senior intelligence officials in Washington were also skeptical about the location (Dahl, 2013, pp. 83–86). This disagreement illustrates how intelligence-gathering and analyses do not happen in a vacuum but in an often fragmented environment where differing intelligence agencies and non-intelligence entities, such as military commanders, can disagree about the available information. Thus, to reduce the existing uncertainty, the intelligence analysts at HYPO proposed a trick in which the garrison at Midway was ordered to transmit a fake radio message on open channels regarding some difficulties with their desalination plant and that they were running short of water. In turn, American intelligence intercepted a Japanese radio transmission mentioning ‘AF running low on water,’ which proved that AF was Midway (Layton et al., 2006, pp. 421–422). Intelligence was therefore mobilized to reduce decision-makers existing uncertainty further and stabilize command. By the end of May, Admiral Nimitz had deployed all available resources to the defense of Midway, which was based entirely on the intelligence received by HYPO.

Key Intelligence Takeaways

The ultimate Battle of Midway proved a critical turning point in the Pacific Theater of WW2, as it halted the Japanese offensive and shifted the strategic initiative to the allies. However, this outcome heavily depended on the work done by American naval intelligence, as it enabled the Americans to set up an ambush for the Japanese. The Battle of Midway, therefore, illustrates several critical takeaways regarding the value of intelligence and how it was used in managing the uncertain environment in which the Americans found themselves during the early stages of WW2.

First, Midway illustrates how intelligence is exceptionally fundamental when on the defensive due to the uncertainty of where the blow will come from, especially when facing a stronger enemy. The Americans found themselves heavily outnumbered and outgunned by an experienced and undefeated enemy; their only chance of success was to concentrate their strength against fractions of the Japanese fleet at the right place and time (Ferris, 2015, p. 661). Accordingly, intelligence managed to not only provide the Americans with the ‘where’ but also the ‘when’ question, as HYPO’s prediction was ‘only five minutes, five degrees, and five miles out’ from where the Japanese were first spotted (Munson, 2016). Thus, although the correct prediction of the Japanese offensive did not guarantee the battle’s outcome, no intelligence at all would have certainly made a similar defensive operation impossible (Schorreck, 1975). In the present day, the importance of intelligence in a defensive conflict is further illustrated by the prominent role of intelligence in modern counter-terrorism due to its unpredictability and inherently defensive nature.

The second takeaway from the Battle of Midway further builds on the first by looking at the environment and battlefield conditions. When facing an environment in which small groups of units are scattered over millions of square miles, such as in the maritime domain, wireless communication methods such as radio are the most valuable means of communication. This characteristic made traditional intelligence methods such as prisoner interrogations and the use of agents less effective as opposed to signals intelligence, radar, imagery, and captured documents (Ferris, 2015, p. 660). In the Pacific Theater, force-to-space ratios were low, with most elements on either side rarely in contact with each other, while their dispositions were masked. In such an environment, possession of the initiative produced tremendous power, as it often required weeks or months to redeploy naval and air forces from one base to another. Accordingly, the opportunity to concentrate your forces against an enemy’s weakness, catch it by surprise and know its intentions proves extremely valuable in such an uncertain environment (Ferris, 2015, p. 661). And intelligence is the only tool that can provide such an advantage, which can be recognized in the present-day maritime domain, such as in counter-piracy operations and regarding the tensions in the South China Sea.

Finally, the examples from the Pacific Theater of WW2 illustrate how the value of intelligence ultimately depends on decision-makers’ willingness to act upon it. The difference in decision-makers’ receptivity towards the available intelligence regarding Pearl Harbor and Midway illustrates how the pre-existing belief in the identified threat and the trust in the intelligence community are vital factors. This also shows how the more precise and tactical the intelligence is, the more likely decision-makers will believe and act upon it (Dahl, 2013, pp. 86–88). This latter point exposes an intelligence paradox, as decision-makers often demand strategic-level intelligence and warnings, which is usually readily available, as we saw with Pearl Harbor. Yet, strategic-level intelligence proves unlikely to be accepted by decision-makers. In contrast, more specific tactical intelligence, which is harder to acquire, is much more likely to be acted upon, as we saw with Midway (Dahl, 2013, pp. 89–90). Indeed, while preparing for Midway, American naval intelligence did not only discover the ‘where’ and ‘when’ questions but also managed to answer the ‘how’ question by uncovering the Japanese order of battle, allowing American forces to always be one step ahead of the Japanese throughout the engagement (Schorreck, 1975). Therefore, such specific and tactical intelligence was more positively received than the strategic-level warnings regarding Pearl Harbor, which were often too general and broad for decision-makers to act upon.

Conclusion

To sum up, the early stages of the Pacific Theater of WW2 perfectly illustrate how intelligence can both reduce the uncertainty of governments and decision-makers in times of war and crises while also showing how the available intelligence can lead to more tension and fragmentation within the intelligence community and chain of command, as the information can be interpreted in many different ways. Thus, as with so many things, the answer to whether intelligence reduces uncertainty or overcomplicates the decision-making process lies somewhere in between. Nevertheless, looking at the Battle of Midway as a historical example, it becomes clear that intelligence proved to be fundamental in managing the engagement, leading to several general takeaways that could inform current and future crises.

Additionally, the examples illustrate how, in the end, it is often not about the intelligence itself but more about the receptivity of the decision-makers. Intelligence cannot solve crises or win wars by itself. Instead, intelligence can make operations more informed and efficient, magnify physical resources by enabling units to fight more effectively, and even improve morale by reducing uncertainty and stabilizing command. Yet, the effect of intelligence is ultimately secondary, as a force-multiplier that holds massive potential if used and listened to correctly.

Bibliography

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Layton, E. T., Pineau, R., & Costello, J. (2006). “And I was There”: Pearl Harbor and Midway—Breaking the Secrets. Naval Institute Press.

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