The parallels are blindingly and painfully obvious. A surprise attack against an Israel caught largely unaware; an invading military force; the timing, a holy day in early October; the victims, an unsuspecting population forced to scramble for underground bomb shelters and mobilize for war; the mistakes by an intelligence apparatus that is the envy of the world.

But the surprise attack that took place in Israel this past weekend is arguably worse than the one that launched the Yom Kippur War of 1973. Hamas, a guerrilla organization that controls the Gaza Strip, has already killed many more Israeli civilians in the first days of this war than Egypt and Syria, sovereign nations with national armies, killed during the October war 50 years ago. Hamas struck targets deep inside Israeli towns. The magnitude and sophistication of this past weekend’s attacks—carried out in multiple locations and involving thousands of fighters—implies that this offensive was in the works for several months, if not longer. And intelligence gathering should have been easier in Gaza, where Israel is reputed to have massive surveillance systems, than it was in Egypt and Syria in the early 1970s. How could Israel have missed the planning of this assault?

The first explanations put forth by experts and journalists suggest that the problem was largely a matter of intelligence collection. Perhaps Israel over-relied on signals intelligence and other electronic sources, and Hamas learned to circumvent detection—for example, by using drones to disable systems along the border. Another possibility is that Israel lacked enough, or credible enough, human intelligence sources within the inner circle of Hamas’s political leader, Ismail Haniyeh, or access to the plans of its military commander, Mohammed Deif. In 1973, the Israelis had a highly placed human source: the late Egyptian President Gamal Abdel Nasser’s son-in-law, Ashraf Marwan, who was also a close adviser to President Anwar Sadat. A third theory is that Israeli intelligence was distracted by a multitude of threats; much of the Israeli military was stationed near the West Bank before this weekend’s attack. Finally, Hamas might have used deception, lulling Jerusalem into assuming the group was willing to live with Israel’s normalization of relations with Arab countries. In 1973, the Egyptians used a regularly scheduled military exercise to cover up their war preparations.

[Andrew Exum: The Israeli military wasn’t ready for this]

But intelligence failures can also be the product of a failure of imagination. The disorganization and slowness of Israel’s response on Saturday strongly suggest that the country’s political and military leaders might suffer from the same psychological misconceptions that Israeli Prime Minister Golda Meir and her advisers—and some in the U.S. government—did in 1973. In both instances, Israel’s leaders appear to have misread their Arab adversaries, grossly underestimating their enemies’ propensity for taking risks and overestimating their own deterrent capability. These mental shortcomings can blind a modern intelligence service, no matter its level of sophistication, and the government it serves. A look back at what went wrong in October 1973, using some materials released in the past decade, provides useful historical context for thinking about the shock of last weekend.  

In the months leading up to the Yom Kippur surprise, Israel received ample warnings about a potential attack. Sadat initially doubted that the Egyptian military could pull off an operation intended to uproot Israel from the lands it had taken in the 1967 Six-Day War. The Israeli air force remained formidable. But by 1972, he’d begun to change his mind. In July, he expelled Soviet military advisers who had helped build the modern Egyptian army but had also cautioned prudence in challenging Israel. Three months later, Sadat informed his military command that he believed the time was right to cross the Suez Canal and recapture much of the Sinai. His goal was to change the politics of the Middle East by restoring Egyptian self-respect and crushing Israel’s sense of superiority. When the Egyptian military’s high command resisted the strategy, he fired half of his top generals. By April 1973, Sadat had readied the Egyptian army for an attack. According to Uri Bar-Joseph, the premier scholar of what Israeli intelligence knew and didn’t know in 1973, Israel’s mole, Marwan, shared details about Sadat’s evolving plans throughout late 1972 and early 1973.

Then came the first war scare. In April, Marwan turned over to the Mossad, Israel’s civilian foreign-intelligence service, the details of Cairo’s plans and said that the Egyptian military would cross the Suez Canal in May. Two weeks later, King Hussein of Jordan sent a secret message to Meir saying that “a major military fiasco in the area is inevitable.” Meir and Defense Minister Moshe Dayan took these messages seriously and, for a time, ignored Major General Eli Zeira, the head of Israeli military intelligence, who argued that Sadat lacked the preconditions to go to war, according to Bar-Joseph. Dayan even ordered the Israeli Defense Forces to prepare to fight.

But Syria’s lack of military readiness forced Sadat to postpone the attack. When May came and went without military action, Zeira’s credibility in Israel rose, while that of the Mossad—and especially its key source, Marwan—sank.

[From the October 2023 issue: Nixon between the lines]

There is no evidence that Israel passed its top-secret information from Marwan onto Washington. Nevertheless, the Nixon administration was watching the situation closely, with its own sources of information, and sensed a crisis. On May 2, the CIA reported to President Richard Nixon, in a since-declassified President’s Daily Brief, that it was “possible that Sadat may be convinced that in the end only military action will generate movement toward a settlement and Egypt’s recent moves could well be preparations for such a contingency.” Still, Washington doubted this would happen. When Israel passed along King Hussein’s war warning to the U.S. government on May 3 and asked for its assessment, the U.S. intelligence community acknowledged that an invasion was possible but concluded that “Egyptian-Israeli hostilities appear unlikely in the next few weeks.” National Security Adviser Henry Kissinger assured Nixon that U.S. intelligence “assumes that Sadat is still operating primarily on the basis of rational calculation,” despite the fact that Sadat’s Arab contacts “have come away from recent conversations with him persuaded that he is in a frame of mind to ‘do something foolish.’” The Soviets, who were eager to reach a second arms-control agreement with Nixon, also warned Kissinger that there might be war in the Middle East. “[W]e dismissed this as psychological warfare,” Kissinger would later admit in his memoirs, “because we did not see any rational military option that would not worsen the Soviet and Arab positions.”

When war didn’t come, the May scare served to reassure those who had been skeptical that Egypt would start a conflict it would lose. Alarmists were looked upon as having cried wolf, even when signals started pouring in that the Egyptians were preparing for war in the fall. “Lulled by the false alarm of May, both Americans and Israelis interpreted these activities as merely more realistic exercises,” Kissinger would later write. At the end of the May crisis, some U.S. officials concluded that Sadat might yet risk a limited war to break the political deadlock in the Middle East, hoping to shock the Israelis into going to the negotiating table. The State Department’s Bureau of Intelligence and Research (INR) advised Secretary of State William Rogers that if there was no diplomatic progress, “our view is that the resumption of hostilities by autumn will become a better than even bet.” But by the fall, Kissinger observed, “strangely enough, INR abandoned its prediction as war actually approached.”

On October 4, 1973, two days before the Yom Kippur invasion, Israel got another dramatic break: Marwan notified the Mossad that he wanted to talk in person with its director. According to Bar-Joseph, Marwan’s message was that he needed to discuss “a lot of Chemistry,” the pre-arranged codeword meaning that an Egyptian attack was imminent. Marwan’s warning was clearer than ever. Israel needed at least 36 hours to call up its reservist forces, so it had sufficient warning, but just barely. Thousands of miles away in Washington, the National Security Agency had also detected clues that an invasion was imminent but apparently failed to convince analysts at the CIA and in the Pentagon. The United States passed along no warning to Israel.

On the morning of October 6, after the Israelis had finally concluded that they should take seriously the intelligence from their mole, the CIA, in another President’s Daily Brief, assured Nixon that “we have no information that would confirm the Israeli reports of an imminent attack.” When Kissinger, who became secretary of state in September 1973, learned that Israel was warning of war, he didn’t take the warning seriously. “First I thought it was an Israeli trick for them to be able to launch an attack although this is the holiest day,” he admitted to Alexander Haig, Nixon’s chief of staff, on October 6. Before U.S. intelligence detected the movement of Arab armies, Kissinger had called the Israelis, worried that they might launch a preemptive strike, and warned them not to.

[Michael Oren: This war isn’t like Israel’s earlier wars]

After months of unheeded warnings, Egypt attacked, and the consequences were felt immediately. More than half of Israel’s tanks were wiped out as Egyptian forces crossed the Suez Canal under cover of Soviet-supplied surface-to-air missiles and established positions in the Israeli-occupied Sinai. In the north, Syria appeared poised to retake the entire Golan Heights.

Given the enormity of this intelligence failure, the Israelis quickly investigated what had happened, establishing the Agranat Commission to look into the matter. The committee concluded that the principal cause was bad analysis, in particular an ironclad assumption regarding Egyptian intentions. According to the commission, Israel’s leadership believed that Sadat would not launch a war he knew he couldn’t win. Any potential military action by the Egyptians—or the Syrians, who would not move militarily without Egypt—was discounted by Israeli leaders as irrational. This bad analysis, which the Agranat Commission called the “conceptzia,” or the “concept,” produced in Israeli leaders what psychologists refer to as cognitive closure—the need for certainty even in the face of new information or mounting evidence.

A postmortem by the U.S. Intelligence Board concluded that the United States similarly was surprised by the outbreak of war because of a misreading of Arab intentions and capabilities. Information gathered by the U.S. intelligence community was “not conclusive but was plentiful, ominous and often accurate,” and was “sufficient” to prompt a warning of war to the president, investigators wrote in December 1973, on behalf of Director of Central Intelligence William Colby. But, the investigators continued, “certain substantive preconceptions, reinforced by official Israeli interpretation, turned the analyst’s attention principally toward political indications that the Arabs were bent on finding nonviolent means to achieve their objectives.”

The postmortem also found that analysts harbored a cultural bias—bigotry, really—against the Egyptians. U.S. analysts tended to underestimate Arab culture, to the point of contempt. Two months after the war, the CIA concluded, “There was … a fairly widespread notion based largely (though perhaps not entirely) on past performance that many Arabs, as Arabs, simply weren’t up to the demands of modern warfare and that they lacked understanding, motivation, and probably in some cases courage as well.”

The Yom Kippur surprise underscores that it’s not enough to get the right information about an enemy—to recruit the right agent, steal the right file, hack the right communications system, or monitor the right movements. Equally important is how individual analysts, and the intelligence system overall, process the information. Before Pearl Harbor, the American intelligence community didn’t have the right dots to connect (the United States had been breaking the Japanese diplomatic cipher, not its naval cipher). Before 9/11, the U.S. intelligence community had the right dots but failed to connect them (some al-Qaeda members known to U.S. intelligence were already in the United States before September 2001). In 1973, both Israel and the United States had lots of dots and connected them but formed the wrong picture with them. Intelligence officers in both countries lacked a dynamic view of the situation or of Sadat himself. They shared the arrogant belief that the Egyptian leader did not have the capacity, ingenuity, or nerve to surprise them. As Kissinger would write, “Sadat, in fact, paralyzed his opponents with their own preconceptions.”

We won’t know for some time exactly what Israeli or American leaders knew prior to the Hamas invasion, or exactly what the group’s political leader, Haniyeh, and its military chief, Deif, were thinking in launching Saturday’s attack. But the costs of underestimation should be well understood now. Less than a decade after the Yom Kippur War, Israel suffered intelligence surprises after misjudging the military capacity and political coherence of Lebanon’s Shia minority. Israel had not predicted that its 1982 invasion of Lebanon would provoke the militarization, with Iranian help, of Shi’a in the south. To this day, the group that emerged, Hezbollah, remains a significant adversary. Similarly, the United States, following 9/11 and the bitter wars in Iraq and Syria with al-Qaeda and ISIS, understands how formidable adversaries in the region can be.

[Bruce Hoffman: Understanding Hamas’s genocidal ideology]

But has this translated into an appreciation of Hamas’s strategic thinking? Or was Israel in 2023 also the captive of an assumption about its enemy? Some of Prime Minister Benjamin Netanyahu’s past public statements seem to imply an expectation that Palestinians would simply go along with other Arab leaders’ recent rapprochements with Israel. “If you open up to the Arab world and you normalize relations with them, it will open the door for an eventual reconciliation and peace with the Palestinians,” Netanyahu said in 2018. “We should do both, but I think you should not underestimate the openness and the thirst in the Arab world today for Israel.” Only six days before Saturday’s attack, according to The New York Times, Israel’s national security adviser, Tzachi Hanegbi, said in a radio interview, “Hamas is very, very restrained and understands the implications of further defiance.”

Although Kissinger had his doubts about Israeli intentions, one key difference between 1973 and 2023 is that the U.S. and Israeli governments are much less aligned today. After years of disagreement, Nixon and Meir had come to an understanding of Israel’s importance as a nuclear deterrent. Joe Biden and Benjamin Netanyahu, however, hold different views of the Middle East. We do not yet know whether Washington reinforced any flaws in Israel’s analytical framework this time around. Some evidence suggests that the United States was less sanguine than Israel about the effects of the Abraham Accords, the recent series of agreements that normalized relations between Israel and a handful of Arab nations. In April of this year, CIA Director William Burns said in a speech: “Despite the promise of the Abraham Accords and progress to a normalization between Israel and more Arab states, tensions in the region, including between Palestinians and Israelis, threaten to bubble over again.” Still, a week before Hamas invaded Israel, National Security Adviser Jake Sullivan told The Atlantic, “The Middle East region is quieter today than it has been in two decades.”

Fifty years ago, Israel and the United States discounted Sadat’s capacity to have a strategic vision that they didn’t understand. Although the players have changed, the danger of underestimation remains the same. Presumably Hamas’s leaders saw a window to stop a possible normalization deal between Israel and Saudi Arabia. Perhaps they hoped to inflame the West’s Palestinian allies on the left, who might respond to any Israeli retaliation by complicating their governments’ approval of the Abraham Accords. Hamas also likely interpreted the deep internal divisions in Israeli society as a sign of weakness that would reduce its military readiness. There is a rationality in all of this. Yet let’s make another point clear: Hamas, unlike the Egyptians in 1973, is targeting civilians and taking hostages. Whatever their strategic motive, they have opted for terrorism.

Still, Hamas might share with Sadat the determination that the only way to upend an unfavorable status quo is by launching a military strike destined to be crushed by Israel. Hamas’s leaders chose to start this war on the anniversary of the last time Israel was caught sleeping. They know that history.