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Aug. 29, 2024

The Fallacy of Unambiguous Warning

Regan Copple
©2024 Regan Copple

ABSTRACT: The Indications and Warnings subfield of intelligence has traditionally divided warnings into a dichotomy of “ambiguous” and “unambiguous” that gives policymakers a false sense of security. This article examines how unambiguous warning has been conceptualized and why it has become an inadequate planning tool that can lead to dire consequences in the quest for certainty. Using the 1973 Yom Kippur War and the Pearl Harbor attack as case studies, the article shows unambiguous warning is an inadequate planning tool that can lead to dire consequences in the quest for certainty. The article concludes with observations about the role of intelligence and the future of military planning.

Keywords: intelligence, military planning, warning, decision making, strategic planning

 

Two years ago, I attended a series of planning discussions with members of the US military. During one session, an officer suggested the plan should define the term unambiguous warning for future readers. Everyone agreed, and the officers each described what they believed constituted a clear, unmistakable, and unambiguous indicator of an impending conflict. All the officers at the table contested their colleagues’ definitions. After more than 90 minutes, the debate grew more acrimonious. At the end of the meeting, the planners were no closer to a shared understanding of unambiguous warning. If anything, the officers held stronger and more divergent views about what constitutes a clear and universally understood signal of impending war.

This anecdote exemplifies the difficulty in identifying precisely when a war will begin. While it may seem obvious that it is impossible to know when and how wars will begin, the fallacy that the Intelligence Community will provide clear, infallible details about this topic pervades the Department of Defense.

The Indications and Warnings subfield of intelligence includes three main categories of warnings. The highest-level political and strategic evidence of adversary preparations for war is known as strategic warning. Once preparations become clearer and additional evidence is gathered on military preparations, intelligence professionals can identify operational or ambiguous warning. Within the final days before a conflict when it is clear that war will begin and final adversary preparations are underway, the Intelligence Community will theoretically provide unambiguous or tactical warning to policymakers and military decisionmakers.

When perfectly executed, indications and warnings from the Intelligence Community can provide decisionmakers valuable information and potential advantages. If not clearly recognized or vaguely communicated to decisionmakers, each type of warning provides limited benefits to the planning process. Missing one link in the chain, a plausible outcome, has happened repeatedly. Douglas Borer, Stephen Twining, and Randy P. Burkett explain that the Intelligence Community successfully developed unambiguous warning for the Tet Offensive, the Korean War, and the Soviet invasion of Afghanistan. Nevertheless, the respective presidents and Department of Defense leadership did not widely recognize these warnings due to their pursuit of alternate and sometimes contradictory policies.1

Historical analyses ranging from World War I to the Rwandan genocide of 1994 all entail stories of surprise and organizations claiming they should have known about impending attacks. If the current warning system—more specifically, the progression from high-level strategic warning to operational ambiguous warning and unambiguous tactical warning—should have worked in these cases, why has it failed to predict military actions so often? The answer lies in the quest for truly unambiguous warning.2

Military planning processes and analyses underpinning US military strategy must avoid the danger of conflating unambiguous warning with certainty. In a world of blurred lines between peace and conflict and sophisticated tools for deception, unambiguous warning has become a fallacy. It is time for US leadership to consider creating plans that do not require unambiguous warning. Instead, decisionmakers should use ambiguous warning when constructing military plans based on an adversary’s posture and readiness to initiate war. To that end, this article examines the warning system’s taxonomy in general and unambiguous warnings within a contemporary context in depth. It then analyzes two historical cases where reliance on unambiguous warnings as the foundation for military planning had catastrophic consequences. Lastly, it offers observations about the future of warfare in an era in which crystal-clear warnings are not guaranteed.

What Is Considered Unambiguous?

Warning is less of a quest to divine specific event predictions and more of a structured intellectual and bureaucratic process for analyzing and understanding intelligence. The United States has constructed a complex system for collecting, analyzing, and disseminating warning intelligence. Still, the nature of interactions between the Department of Defense and the rest of the executive branch has created a multistep process in which individuals with diverse roles view information before it finally reaches policymakers with the authority to enact decisions. Consequently, multiple places in the warning process could generate incorrect perceptions or estimates that may impede the ability to recognize threats and act on warnings successfully.3

To generate strategic, operational, or tactical warnings, Thomas G. Mahnken identifies a four-part chain the Intelligence Community and the decisionmakers must follow.

  1. Initially, there is an enemy action, which a state’s intelligence apparatus can either collect or fail to observe.
  2. If collected, the data will be sent to intelligence analysts for processing, evaluation, and analysis. In this step, the analysts will either interpret or misinterpret the data based on their understanding or misunderstanding of the enemy’s action or motivation.
  3. Subsequently, the interpretations are presented to decisionmakers who can choose to take action—or not.
  4. Lastly, decisionmakers who decide to act can take he correct action that benefits them, the incorrect action, or no action at all, which may create additional damage when an attack occurs.

Even if information moves from collection to a correct and actionable decision, it is not designed to predict specific events. Once a piece of information goes through Mahnken’s process, the Intelligence Community assesses the probability of the intelligence leading to conflict according to three levels of confidence: high, moderate, or low. High confidence is associated with unambiguous warning. Moderate- and some low-confidence assessments are correlated with ambiguous warning.

Any assignment of warning, whether ambiguous or unambiguous, is subjective. The Intelligence Community specifies its level of confidence to avoid providing policymakers and military leaders with a false sense of precision in its estimates. This terminology creates opacity between intelligence professionals and the rest of the national security community, which often does not understand the difference between a moderate- and high-confidence assessment. Hence, there is usually room for interpretation and varying views on the significance, impact, and meaning of most Indications and Warnings intelligence.4

The Russia-Ukraine War shows how all the pieces of Indications and Warnings intelligence work together to inform decisionmakers properly and predict the beginning of conflict correctly. American and British intelligence services warned their respective governments of a Russian attack on Ukraine three months in advance. Coupled with open Russian public statements about its desire to annex Ukrainian territory, the strategic warning was clear. Russian mobilization and mass military movements from the central and western military districts toward the Russia-Ukrainian border constituted operational ambiguous warning. Then, on February 19, 2022, days before the initial artillery and rocket bombardment, the setup of field hospitals near the border constituted a tactical warning of impending Russian invasion.5

The US Intelligence Community lauded its predictions about the Russia-Ukraine War as the ideal case study of intelligence collection and analysis. The intelligence process and bureaucracy worked correctly and provided leaders with an accurate picture of Russian war preparations. In the terminology of Joint Intelligence, Joint Publication 2-0, the doctrinal document governing intelligence operations, the US Intelligence Community provided “timely, accurate, [and] useable” assessments of what was about to happen in Ukraine. Based on this knowledge, the Russia-Ukraine War appears to be an intelligence success story. At the same time, however, while the United States successfully predicted when the invasion would begin, states like Germany and France were caught off guard due to their refusal to believe Vladimir Putin was serious about invading Ukraine. The warning system led to success in Ukraine but failure almost two years later in Israel. It is not the idea of unambiguous warning that is dangerous but the conflation of unambiguous warning with certainty that removes critical thought.6

Of the historical cases in which regional or global powers expected to receive unambiguous warning, two deserve special attention. The Yom Kippur War provides an example of when a militarily powerful state (Israel) had abundant evidence that its adversary (Egypt) intended to initiate a war but failed to look for the correct tactical indications of conflict. Next, the Japanese attack on Pearl Harbor highlights how one of the global powers of the era misread the strategic environment and ruled out an attack, despite several internal warnings from US Navy staff.

The Yom Kippur War and the Erosion of Normalcy

The Yom Kippur War is traditionally referred to as a case of “strategic surprise” in which Israel failed to recognize Egyptian preparations for a major war on its southern border. Before 1973, Israel assumed Egyptian forces would provide 48 hours of unambiguous warning via observable actions, allowing Israel time to call up and mobilize the Israel Defense Forces (IDF) reserves and transport them to the border. To some extent, the surprise attack reflected a psychological pathology within Israel more than a failure of warning.7

Government analysts and leaders failed to predict when the war would begin because they could not combine and synthesize information in a way that would reveal Egypt’s capabilities and intent. The earliest indication Egypt was interested in resolving its political disputes by military means came near the end of 1972, when Egypt began a force buildup focused on acquiring additional fighter aircraft, surface-to-air missiles, and anti-tank missiles from the Soviet Union. Nevertheless, an increase in military acquisitions alone is not an effective indicator of when a war will begin.8

Often, a more effective means of determining a state’s readiness to initiate a war is to examine what preparations and movements the state is undertaking in accordance with its military doctrine. Egyptian doctrine, based on Soviet doctrine, required a comprehensive bombing campaign aimed at disabling an enemy’s airpower to begin any conflict. The goal behind this strategy was to knock out Israel’s advanced tactical airpower before it had the chance to take off and inflict damage on the Egyptian Air Force. Consequently, IDF Intelligence Director Major General Eli Zeira monitored image-based and human intelligence reports of Egyptian airfields for signs of preparations for a sweeping bombing campaign. Given Egypt’s extensive use of air strikes during the opening hours of the Six-Day War in 1967, Zeira believed the Egyptian Air Force unable to execute any action until winter 1973 at the earliest. What Zeira did not know was that Egypt planned to deviate from its previous doctrine after judging the strength of Israel’s air defense network and assessing Egypt’s Air Force would take unacceptable losses to conduct a strike. Instead of launching a bombing campaign against Israeli airfields, Egypt planned to cross the Bar-Lev Line with ground forces before executing a breakout across the Sinai Desert.9

To accomplish this plan without raising Israel’s suspicions, Egypt began holding its yearly Tahrir exercises (that depict an invasion of Israel near the Bar-Lev Line adjacent to the Suez Canal) beginning in the late 1960s. The goal of the exercises was to normalize the presence of Egyptian forces near Israel’s southern border and to condition Israeli intelligence to expect yearly surges of troops to the border without generating a response from the Israel Defense Forces. Over time, Egyptian Army officials lulled Israeli intelligence analysts into a false sense of security by creating a new military pattern of life, even as preparations to move more troops and materiel to the border for the October exercise were underway.10

In addition to altering their pattern of life, Egyptian military officials sent mixed signals to Israel to obscure its estimates of Egypt’s preparation timeline. Approximately one week before the war began, Egypt announced the mobilization of four divisions of reservists to participate in its yearly exercises at the Sinai border. While this information would have been a significant warning any other time of year, Egypt had issued a public notice that 20,000 reservists had been released from their reserve call-up one week later, seemingly signaling that Egypt was conducting an exercise, not planning for imminent war.11

Egypt’s plan to deceive Israel into complacency was an operational success. The IDF’s senior leadership only realized Egypt would not conduct another yearly exercise when additional infantry brigades and munitions were already en route toward the Suez Canal on October 5. By then, it was too late. Israel issued a partial reserve call-up the morning of October 6, an action it had previously planned to take at least two days before the beginning of a war.12

The failure of IDF and Mossad intelligence to provide an unambiguous warning can be attributed to two factors. First, IDF intelligence was looking for the wrong actions, causing them to miss indicators of an upcoming attack. Concentrating on the Egyptian Air Force’s readiness levels caused IDF intelligence to overlook more significant signs that alternative war preparations were underway. Interpretation, the second step in the warning development process, was equally disadvantaged, due to “the Concept” that was accepted as reality within Israeli intelligence services. The Concept was an informal and broadly accepted checklist of actions that, when combined, would constitute warning. This checklist dictated that Egypt would not go to war unless it had a long-range aerial strike capability and sufficient Scud missiles to prevent an Israeli counterattack deep into Egypt.13

In this case, Israeli intelligence fell victim to the first two steps within the Indications and Warnings process by not collecting the correct types of actions and misinterpreting the actions upon which it had collected intelligence. Furthermore, entrenched biases—including the belief that the Israeli military would deter Egypt de facto because Anwar Sadat knew the Israeli forces were superior to Egyptian forces—meant Israeli leadership was not attuned to the right signs that war was on the horizon in the first place.14

Next, the long-standing deceptive pattern of life created a benign explanation for Egyptian war preparations and primed Israeli intelligence analysts to misinterpret signals. Rather than attributing Egyptian exercises to preparations for war from the start, Israel assumed these actions fit the pattern of yearly exercises—a pattern it believed would continue until Egypt became stronger and confident enough to mount an invasion. The dismissal of the Egyptian reservists on October 4 offered an additional piece of contradictory information to sow doubt and generate uncertainty among Egypt-watchers in Israel. The Egyptian Army knew it did not have to pull off a complete surprise attack, it simply had to generate enough contrary information to prompt Israel to misinterpret warning signals and thus fail to issue a reserve call-up two days before the invasion.15

Israel’s inability to achieve unambiguous warning did not lie in a lack of information but in confusion about the information the Israeli intelligence apparatus had observed. The active steps Egypt took to deceive the Israeli military generated doubt about Egyptian plans and intentions among a set of intelligence analysts and policymakers. Egyptian behavior before October 6 did not fit the IDF’s predetermined archetype about what an Egypt preparing for war would look like, and this oversight generated the opportunity Egypt exploited in the opening days of the Yom Kippur War.

Fifty years later, Israel suffered from the same mistakes when Hamas launched a barrage of thousands of missiles coupled with paragliders and an armored breakthrough of the wall between Israel and Gaza in its October 2023 Operation Jericho Wall, Hamas’s armed incursion into Israel and hostage-taking operation. Much like the Egyptian attack against Israeli positions in the Sinai, officials within Unit 8200 dismissed Operation Jericho Wall. They deemed the intelligence report “aspirational” and “totally imaginative” 14 months before the attack caught Israel by surprise.16

Much like the Yom Kippur War, Israel collected intelligence in advance of the October 7 attacks that was misinterpreted and not considered unambiguous warning. The prevailing assumption within the Israeli Intelligence Community—that Operation Jericho Wall was beyond Hamas’s sophistication and was implausible due to the likely Israeli response—did not factor in what Hamas believed it could gain from the attacks, nor did the Israeli Intelligence Community consider that Hamas’s perception of rationality could look different from its own.

After the Yom Kippur War concluded, Israel initiated the Agranat Commission to internalize lessons from the war and generate policy recommendations to prevent similar surprises. One conclusion from the commission’s report was that Israel should institute reforms to allow for more diverse perspectives and dissenting opinions within intelligence analysis. Fifty years later, the same institutional pathologies reemerged and led to a similar surprise that left the Israeli prime minister and military leaders scrambling to craft a response.17

World War II and Pearl Harbor

In contrast to the Yom Kippur War, the two weeks preceding the Japanese air raid on Pearl Harbor demonstrate the possibility for military intelligence to do almost everything right—from collecting signals to receiving warnings from higher command echelons—but still fail to achieve the correct type of unambiguous warning. On November 27, 1941, the US Navy issued a war warning order, cautioning that Japanese naval forces appeared postured for a “sudden aggressive move in any direction,” though Navy intelligence analysts in Hawaii predicted any aggression from Japan would take the form of an assault on the British territory of Malaya.18

The Army G-2 within the Hawaiian Department also tracked Japanese movements and identified threats to the Hawaiian Islands. Unlike the Navy, the Army had significantly less warning because the Navy’s war warning was not shared with the Army G-2. While General Walter Campbell Short, commander of the Army Hawaiian Department, knew of the war warning message, he and Admiral Husband Edward Kimmel were under strict orders to disseminate the warning to the fewest number of individuals necessary to maintain the security of their intelligence sources.19

Three days after the Navy issued its war warning, Imperial Japanese forces changed their radio call signs to obfuscate communications American forces intercepted. As the Imperial Japanese Navy sailed toward Hawaii, the fleet engaged in radio silence, and land-based naval forces continued to transmit false radio traffic to confuse American intelligence analysts monitoring the location of all Japanese aircraft carriers. After the attack, Lieutenant Commander Edward T. Layton revealed that he did not take the lack of radio traffic as an indicator and assumed the Japanese carriers were still in home waters since carrier groups underway displayed different patterns of behavior and radio communications than those of ships in port.20

The final warning came one hour before the attack. Army Air Warning Service radars on Oahu picked up a group of aircraft moving toward the island at 7:02 a.m. After radar operators called into Fort Shafter to report the event, Kermit Tyler, the Navy lieutenant on duty, told the two privates manning the radar they were seeing a flight of B-17 bombers returning to base from the mainland and instructed them to disregard what they were seeing. Tyler did not make radio contact with the incoming aircraft to confirm if they were friendly.21

All these signals amounted to ample warning, but the United States continued to search for unambiguous warning before acting. The United States had observed several clear actions from Japan, from readying their carrier groups in home waters to the Japanese destruction of their diplomatic codes to identifying incoming Japanese aircraft on radar. Navy intelligence had correctly predicted since October 1941 that Japan was preparing for war, likely to launch an initial attack sometime in early December. The two decisionmakers in Hawaii, Kimmel and Short, could have taken action but waited for additional information that would have further dispelled ambiguity and illuminated what actions to take.22

Furthermore, military leaders in Washington and Hawaii should have already been mentally primed for the possibility of a Japanese air raid. War Plan Orange war games at the US Naval War College and in Washington began with the Red team, playing Japan, attacking Pearl Harbor via carrier-based aircraft. On December 30, 1940, Rear Admiral Claude C. Bloch, commandant of the Naval Forces in Hawaii, submitted a memo to Navy leadership cautioning that the first blow from Japan against the United States would likely be an air strike on Pearl Harbor. The surprise at Pearl Harbor demonstrates that even in scenarios in which there has been extensive planning and forethought about a possible attack, it is difficult for an action to make it through the entire warning process to generate the correct actions from decisionmakers.23

Additionally, the miscommunication between the Army and the Navy in the weeks leading up to the Pearl Harbor attack highlights an important tension operating in the background of the warning process. The Navy intentionally did not share its war warning message or its discovery of Japanese code burning at diplomatic outposts, often a sign that a country expects to abandon its consulates and embassies on short notice within days. At the same time, even though it turned out to be a false flag, the Army did not share with the Navy their knowledge of the “winds code,” a hypothesis that certain phrases in Japanese weather broadcasts were covert orders indicating where Japan would attack next.24

The Army and Navy were under directives from Pentagon service leaders to share their information with the minimum number of intelligence officers necessary to maintain operational security and protect sensitive intelligence sources. In Pearl Harbor’s case, however, the Navy kept relevant information from the Army G-2, which would have cued the Army that sabotage on Oahu was not Japan’s most likely course of action. While protecting intelligence sources and compartmentalizing intelligence are key to maintaining secrecy from an adversary, the same security protocols can harm organizations with the same goals from doing duplicative work or misinterpreting actions due to a lack of evidence.25

Conclusion

Indications and Warnings intelligence conveys predictions and probabilities, however, there is an increasingly common sentiment in Washington below the flag officer level that unambiguous warning will always occur with sufficient time to undertake final military preparations, movements, and posture modifications. While US intelligence capabilities are some of the most advanced in the world, that advantage does not mean military and civilian decisionmakers will correctly interpret, understand, and act on the information received.

For every Ukraine, there have been dozens of Yom Kippur War, Jericho Wall, and Pearl Harbor scenarios. The Department of Defense must now shift its planning processes to expect a lack of unambiguous warning. While the recent shift from the “ambiguous” and “unambiguous” taxonomy toward a corresponding “warning of war” and “warning of attack” framework is a step in the right direction, it still leaves room for misinterpretation and wishful thinking.

Military doctrine and technology have changed since the end of World War II, but the potential for surprise is equal, if not even greater, today. Surprises like the October 7 attack in Israel should remind US leadership and military planners that miscalculations and failure to identify warnings of impending wars will continue. The Intelligence Community must continue to collect, analyze, and properly interpret information and clearly present it to decisionmakers who can choose to take action—or not—before an impending attack occurs. Recognizing signals of conflict in hindsight does not constitute an effective strategy.

 

Acknowledgments: The author would like to thank Thomas G. Mahnken, Travis Sharp, a panel at the Center for Strategic and Budgetary Assessments, and two anonymous reviewers for their helpful comments and ideas to improve this article.

 

Regan Copple
Regan Copple is a research associate at the Institute for Defense Analyses in Alexandria, Virginia, where her work focuses on strategy development and war gaming. She is also an incoming doctoral student at George Mason University.

 

Endnotes

  1. James J. Wirtz, “Indications and Warning in an Age of Uncertainty,” Journal of Intelligence and Counterintelligence 26, no. 3 (Spring 2013): 550–62; and Douglas Borer, Randy P. Burkett, and Stephen Twining, “Problems in the Intelligence-Policy Nexus: Rethinking Tet, Korea, and Afghanistan,” Intelligence and National Security 29, no. 4 (Winter 2013): 811–36. Return to text.
  2. Alexander L. George and Jane E. Holl, The Warning-Response Problem and Missed Opportunities in Preventive Diplomacy (New York: Carnegie Commission on Preventing Deadly Conflict, May 1997). Return to text.
  3. Lani Kass and J. Philip London, “Surprise, Deception, Denial, and Warning: Strategic Imperatives,” Orbis 57, no. 1 (Winter 2013): 59–82. Return to text.
  4. Daniel Irwin and David R. Mandel, “Communicating Uncertainty in National Security Intelligence: Expert and Nonexpert Interpretations of and Preferences for Verbal and Numeric Formats,” Risk Analysis 43, no. 5 (2023): 943–57. Return to text.
  5. Shlomo Shpiro, “Intelligence and the Ukraine War: Early Lessons and Research Roadmap,” National Security and the Future 24, no. 1 (Spring 2023): 7–18; Huw Dylan and Thomas J. Maguire, “Secret Intelligence and Public Diplomacy in the Ukraine War,” Survival 64, no. 4 (Summer 2022): 33–74; Ofer Fridman, “Inherent Strategic Ambiguity Between Objectives and Actions: Russia’s Information War,” Defense Strategic Communications 12, no. 1 (Spring 2023): 211–13; and Julie Coleman, “New Satellite Photo Appears to Show a Sign Russia Has Been Readying for War as Its Forces Surround Ukraine,” Business Insider (website), February 15, 2022, https://www.businessinsider.com/satellite-photo-field-hospital-russia-ukraine-experts-2022-2. Return to text.
  6. Julian E. Barnes and David E. Sanger, “Accurate U.S. Intelligence Did Not Stop Putin, but It Gave Biden Big Advantages,” New York Times (website), February 24, 2022, https://www.nytimes.com/2022/02/24/world/europe/intelligence-putin-biden-ukraine-leverage.html; Joint Chiefs of Staff (JCS), Joint Intelligence, Joint Publication 2-0 (Washington, DC: JCS, October 2013), xi; and Stefan Meister, “Germany’s Role and Putin’s Escalation Dominance in Ukraine,” Russia File (blog), Wilson Center (website), April 5, 2022, https://www.wilsoncenter.org/blog-post/germanys-role-and-putins-escalation-dominance-ukraine. Return to text.
  7. Abraham Ben-Zvi, “Between Warning and Response: The Case of the Yom Kippur War,” International Journal of Intelligence and Counterintelligence 4, no. 2 (Winter 1990): 227; Hanoch Bartov, Dado: 48 Years and 20 More Days: The Full Story of the Yom Kippur War and of the Man Who Led Israel’s Army, trans. Ina Friedman (Tel Aviv: Ma’ariv Book Guild, 1981): 16–20; and Moni Chorev, “Surprise Attack: The Case of the Yom Kippur War” (master’s thesis, National Defense University, 1996), 6–9. Return to text.
  8. Michael Handel, “Intelligence and the Problem of Strategic Surprise,” Journal of Strategic Studies 7, no. 3 (Winter 1984): 229–81; and Mohamed Heikal, The Road to Ramadan (London: HarperCollins, 1975), 22. Return to text.
  9. Uri Bar-Joseph and Arie Kruglanski, “Intelligence Failure and the Need for Cognitive Closure: On the Psychology of the Yom Kippur Surprise,” Political Psychology 24, no. 3 (Summer 2003): 75–99; Meir Finkel, On Flexibility: Recovery from Technological and Doctrinal Surprise on the Battlefield, trans. Moshe Tlamim (Stanford, CA: Stanford University Press, 2007), 170; Chorev, “Surprise Attack,” 6; and Jonathan M. House, Combined Arms Warfare in the Twentieth Century (Lawrence: University Press of Kansas, 2001), 231–40. Return to text.
  10. Uri Bar-Joseph, The Angel: The Egyptian Spy Who Saved Israel (London: HarperCollins, 2016), 166–76; and Uri Bar-Joseph, “The ‘Special Means of Collection’: The Missing Link in the Surprise of the Yom Kippur War,” Middle East Journal 67, no. 4 (Autumn 2013): 540. Return to text.
  11. George W. Gawrych, The Albatross of Decisive Victory: War and Policy between Egypt and Israel in the 1976 and 1973 Arab-Israeli Wars (Westport, CT: Greenwood Press, 2000), 151–53, 155. Return to text.
  12. Bar-Joseph, “ ‘Special Means,’ ” 539; and Chorev, “Surprise Attack,” 6. Return to text.
  13. Bar-Joseph, “ ‘Special Means,’ ” 534, 540. Return to text.
  14. Ephraim Kahana, “Early Warning versus Concept: The Case of the Yom Kippur War 1973,” Intelligence and National Security 17, no. 2 (June 2002): 81–104. Return to text.
  15. Kahanna, “Early Warning,” 84; and Abraham Rabinovich, The Yom Kippur War: The Epic Encounter That Transformed the Middle East (New York: Random House Books, 2004), 25–31, 35. Return to text.
  16. Ronan Bergman and Adam Goldman, “Israel Knew Hamas’s Attack Plan More Than a Year Ago,” New York Times (website), December 2, 2023, https://www.nytimes.com/2023/11/30/world/middleeast/israel-hamas-attack-intelligence.html. Return to text.
  17. Agranat Commission of Inquiry Interim Report (Israel: Center for Israel Education, April 1974), 4. Return to text.
  18. Roberta Wohlstetter, Pearl Harbor: Warning and Decision (Stanford, CA: Stanford University Press, 1962), 45. Return to text.
  19. Wohlstetter, Pearl Harbor, 60–61. Return to text.
  20. Philip H. Jacobsen, “Radio Silence of the Pearl Harbor Strike Force Confirmed Again: The Saga of Secret Message Serial Numbers,” Cryptologia 31, no. 3 (June 2007): 223–32; and Wohlstetter, Pearl Harbor, 48. Return to text.
  21. Erik J. Dahl, “Why Won’t They Listen? Comparing Receptivity in Intelligence at Pearl Harbor and Midway,” Intelligence and National Security 28, no. 1 (February 2013): 76. Return to text.
  22. Wohlstetter, Pearl Harbor, 51. Return to text.
  23. Gordon Prange, Katherine V. Dillon, and Donald Goldstein, At Dawn We Slept: The Untold Story of Pearl Harbor (New York: McGraw-Hill Publishers, 1981), 45, 253. Return to text.
  24. Wohlstetter, Pearl Harbor, 52. Return to text.
  25. Wohlstetter, Pearl Harbor, 45. Return to text.
 

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