9/11 Didn’t Make America Immune to Strategic Surprise

A quarter-century has passed since the deadliest terrorist attack in history. Americans will remember the 2,977 people murdered on Sept. 11, 2001. Yet remembrance is not immunity. As the catastrophe recedes, the officials who lived through it retire and procedures harden into routine; the reforms themselves can breed a quiet confidence that the same failure cannot recur. Gradually, a living warning becomes history.

I know how that happens because I lived it. In August 2023, I led a conference at the Israeli Military Intelligence Directorate marking 50 years since the Yom Kippur War, Israel’s defining experience of strategic surprise. In 1973, despite mounting warning signs, Israel’s leaders clung to the mistaken assessment that Egypt and Syria would not attack. On Oct. 6, they did. 

Barely two months after that conference in 2023, I woke to air-raid sirens as Hamas launched its horrific terrorist attack on Oct. 7. Fifty years and one day after the Yom Kippur War began, Israel had been surprised again. I later served on the directorate’s internal review team. The experience drove home a hard truth: a lesson can be learned, institutionalized and still forgotten.

Israel is hardly unique: the same nation can be caught more than once. America was surprised at Pearl Harbor and again, nearly 60 years later, on 9/11; Russia at Port Arthur and the Soviet Union when Nazi Germany launched Operation Barbarossa; India by China in 1962 and Pakistan’s incursion at Kargil in 1999. The circumstances change, but the pattern holds because the deepest causes of surprise are human and institutional.

Consider the American case. America responded seriously to 9/11, overhauling its intelligence agencies and breaking down barriers to intelligence sharing. But the failure beforehand was not a simple absence of warning. The 9/11 Commission titled its account of that summer “The System Was Blinking Red.” Much of the information was there; the system failed to turn scattered signals into a new picture of the enemy.

Something similar preceded Oct. 7. Israel was convinced Hamas had been deterred, and that its surveillance and high-tech barrier could stop any large assault. That conviction became the lens for every new report, so contrary evidence was folded into the picture instead of breaking it. The problem is often not simply too little information. Sometimes the decisive signals are buried in a flood of data. On the night of Oct. 6–7, numerous signals accumulated, but the prevailing assessment made it easier to explain the anomalies away than to act on them.

It is tempting to hope technology can cut through the noise. Artificial intelligence can help by sifting vast datasets and flagging anomalies a tired analyst would miss, but it is no magic answer. The data it receives and the questions we ask it are still chosen by people. Given the same evidence, AI can reinforce either an alarm or a case for silence, depending on the assumptions built into the task. If an organization’s assumptions cannot be challenged, technology only optimizes the mistake.

The real work is human, and it begins with strategic humility. Commanders and intelligence chiefs must work from the assumption that they may be wrong, perhaps are already wrong, in their deepest convictions about the enemy. They must be the first to question their own judgments, because the mistakes of the best and brightest are the most dangerous: their judgment carries the most authority and meets the least resistance. When evidence diverges from the assessment, the instinct should be to dig into the gap, not explain it away.

Humility also means resisting the pull toward uniformity, both in the evidence an agency elevates and the voices it lets into the room. It should preserve the reports that don’t fit and mix analysts of different training with outsiders willing to challenge what others no longer question. The hardest voices to hear are often the most junior: the people closest to the ground, whose warnings are easy to dismiss as naïve or inexperienced. The real test is whether they can carry an unwelcome judgment to the top and be taken seriously.

Leaders must also protect time for reflection, because an organization too busy to think will eventually be too busy to see. Imagination and exercises cannot predict the next surprise, but they can expose blind spots before an enemy does. Because warning will sometimes fail, a government must build resilience in advance: command systems that survive a first blow, and responses rehearsed for scenarios no one quite believes.

In “The Boxer,” Simon and Garfunkel describe a man who “hears what he wants to hear and disregards the rest.” As it marks a quarter-century since 9/11, America should resist that instinct and the comfortable idea that its reforms have settled the matter. Israel’s painful experience is a warning that even sweeping reforms offer no lasting immunity. America should learn from it and act now: assume the next surprise attack is only a matter of time, and use that time to make it harder to carry out and less catastrophic when it comes.

Or Horvitz, a retired lieutenant colonel, served for 18 years in Israeli military intelligence and was a member of its internal review team on the Oct. 7 intelligence failure.