“Increasingly, some people are saying that terrorism is not that big a threat. That is really going back to the mentality of pre-September 11, 2001. I’m not saying that every day the sky is going to fall. But if we don’t recognize the struggle we are in as a significant existential struggle then it is going to be very hard to maintain the focus.”
– Michael Chertoff, former Secretary of the Department of Homeland Security[1]
“Absolutely.”
– Barack Obama, in response to the question, “Do you think the media sometimes overstates the level of alarm people should have about terrorism . . . ?”[2]
The worst part about senior year in high school in California was waking up extra early on Tuesday mornings to attend model UN meetings. We had to be there at 7 a.m., which was grueling for a nerdy night owl like me, but I usually made it on time… barely. On one memorable Tuesday morning, September 11, 2001, I was running very late and racing to get to school on time. Still, I wasn’t late enough to forget to turn on the radio. The radio hosts were frantically and nervously talking over each other about the news of a plane crash in New York City. That was the first time I heard about the 9/11 attacks. School was de facto cancelled for the rest of the day as I was glued to the television except between class periods, eating lunch, and calling my parents to tell them to turn on the news. Fox News, CNN, the radio, and newspapers dominated my time for days as they did for millions worldwide.
Watching one of the towers collapse on TV was surreal. I remember the confusion, “Did it fall?!” a classmate gasped as we all saw the buildings and thousands of people replaced by a cloud of rubble, smoke, and death. That day changed the United States forever and definitively ended The Nineties, a decade of global prosperity when the US, global capitalism, and democracy were ascendant. What followed was war, shrinking civil liberties, Islamism, bigger government, nationalism, fear, an Axis of Evil, and nativism. In a sign of the times, my father made me peel the “Don’t Steal, the Government Hates Competition” bumper sticker off my car. He thought it was unseemly in a time of war and might even attract vandalism. Many drivers put mini-American flags on their car antennas or flying off plastic clips hanging on their side windows to show patriotic fervor. An age of terrorism and a global war against it had arrived. The country was suffering, but it was a good time to be a terrorism expert.
Terrorism analysis is a vocation that attracts hysterical doomsayers who are willing to trade an almost unlimited amount of wealth and liberty for an infinitesimal reduction in the low chance of terrorism. The most rational among them call terrorist attacks “low probability and high-cost events.” That’s half right, and even that analysis gives terrorists too much credit. Terrorism is a low-probability and low-cost event, on average. The most expensive thing about terrorism is how terrorized people and countries react. They pass expensive counter terrorism laws, restrict civil liberties, start wars, demonize foreigners, and restrict immigration. Sound familiar? It’s a short history of American policy since 9/11, served with a side of freedom fries.
Most terrorist attacks don’t kill or injure anybody. It’s counterintuitive to realize that, especially to those of us who watched the Twin Towers fall on TV, saw it firsthand, or experienced the world change in response, but the facts are plain as vanilla. Terrorists aren’t very deadly. Of all of them, only some are foreign-born, like the 9/11 hijackers, but few immigrants are terrorists, and they are not coming to blow you up.
What Terrorism Means
Terrorism is the pornography of violence – we know it when we see it.[3] But we still have to strive to define it to have any hope of rationally discussing it. Repeating from an earlier chapter: Terrorism is political violence that isn’t committed by the government. Terrorism is a specific crime defined by the motivations of the attackers, like many other crimes. A bank robber who holds tellers hostage terrifies them as he empties the vault, but his goal is to take the money and run. Terrifying hostages is not part of his normal criminal motivation to rob because it is a tactic he uses to successfully get the money. Political change is not the goal. The terrorist’s goal is to change the world by affecting politics, economics, religions, or to achieve other broader social goals like protecting the environment, changing the United States, or spreading ideologies like Islamism. Hate crimes targeting individuals based on their religion, race, or other characteristics are more difficult to distinguish from terrorism, and most experts don’t have a good way of separating the two, but we can work with that.
Governments can’t be terrorists; they must be “non-state actors,” as the experts say. Excluding governments from the definition of terrorism is odd at first blush. Still, it makes sense because terrifying people by using violence for political, economic, social, or other goals is the raison d’être of governments. By that definition, most actions by a government would be terrorism, which would make the word useless when discussing the issue widely. The term “terrorism” is useful to describe those who pursue government-like “big picture” goals from outside the government, often by pressuring it with private violence.
State-sponsored terrorism is a hybrid where the government supports terrorists via subsidy or by providing a safe haven for them, usually as they attack or plan attacks against people abroad or foreign governments. Taliban-ruled Afghanistan protected al Qaeda terrorists before the 2001 US invasion. Saddam Hussein’s Iraq did not shelter terrorists despite repeated claims by President George W. Bush, Vice President Dick Cheney, Colin Powell, and other American government officials to justify the 2003 invasion. The main argument for the invasion was that Saddam had nuclear, chemical, and biological weapons programs and that he would give those weapons to terrorists – a handover that would be easier because Iraq was harboring them. Don’t think too hard about how illogical it would be for a dictator of a small country to want to hand over weapons of mass destruction to terrorists that would certainly be traced back to him if they are ever used; there’s no reason there. Most Americans ignored the absurdity of the argument at the time too.
On September 25, 2002, President Bush said, “You can’t distinguish between al Qaeda and Saddam when you talk about the war on terror.”[4] Speaking the next day on the same subject, Bush continued with, “There are al Qaeda terrorists inside Iraq. The regime is seeking a nuclear bomb, and with fissile material, could build one within a year.”[5] On October 14, 2002, Bush said Saddam “is a man that we know has had connections with al Qaeda. This is a man who, in my judgment, would like to use al Qaeda as a forward army.”[6] On February 6, 2002, Bush put it all together when he said:
One of the greatest dangers we face is that weapons of mass destruction might be passed to terrorists, who would not hesitate to use those weapons. Saddam Hussein has longstanding, direct and continuing ties to terrorist networks. Senior members of Iraqi intelligence and al Qaeda have met at least eight times since the early 1990s. Iraq has sent bomb-making and document forgery experts to work with al Qaeda. Iraq has also provided al Qaeda with chemical and biological weapons training.[7]
None of this turned out to be true, but the world only definitively learned that after the invasion, when the US was well on the way to sacrificing thousands of American lives, hundreds of thousands of Iraqi lives, and many trillions of dollars for nothing. American intelligence experts and administration officials weren’t sending their best. But some, I assume, are good people.
When terrorist movements are big and well-organized enough, they become insurgents who want to take over the government, have the potential military means or organization to do so, and the desire to form their own regime. Many governments have historically begun as insurgents, others with a more remote and distant history of being terrorists, and still others as bandits, invaders, or from local communities banding together to defend against all the above. The history of the Taliban in Afghanistan follows this pattern.
They were founded in 1994 by Mullah Mohammad Omar, who led a group of mostly religious students who had been educated in Pakistani madrassas. Omar eventually let the Taliban take over most of the country by 2001. They promised to restore order, enforce Sharia in post-Soviet invasion Afghanistan, and provide a safe haven for al Qaeda. They courted Islamist Arabs who, in turn, committed terrorist attacks against the Taliban’s Afghan enemies on their behalf. The Taliban then retreated to the mountains when the US invaded in 2001, emerging as terrorists and insurgents who eventually took over the country again in 2021. Omar remained a symbolic figure during their second insurgency, only dying in hiding in 2013 from tuberculosis.
The Taliban’s multiple transitions from insurgent-terrorist to government back to insurgent-terrorist and then back to government are unusually clear and reminiscent of the revenue-maximizing stationary bandit theory of government. In that theory, bandits loot an area and then move on until one chieftain gets the wits to stay put to loot continuously. By becoming stationary, he can capture a constant stream of loot. The chieftain then wants to make sure he gets as much loot as possible, so he makes plunder regular by turning looting into taxation that he seeks to maximize. He also resolves disputes between the people he rules so they can spend more time working to pay taxes instead of fighting. He then defends the area from other barbarians so he can keep all the revenue for himself. This is called national defense. Lastly, he punishes those he rules when they don’t cooperate. The Taliban largely followed this pattern. Other governments started by pooling resources for big projects like diverting rivers for intensive irrigation by centralizing violence.[8] Governments often send people who have many problems, and they bring those problems with them. Some, I assume, are perhaps good people.
Defining terrorism by the attackers’ motivations is another step in maintaining law and order. American Anglo-Saxon jurisprudence considers the intentions of criminals when deciding which crime to charge them with. Premeditated intentional homicide, also known as murder in the first degree, is more harshly punished than manslaughter or the accidental killing of somebody. Intentional murder in the spur of the moment is between those two extremes, more severely punished than manslaughter but less than premeditated murder. Adding terrorism on top of murder or attempted murder is an extension of motivational reasoning applied to other crimes like arson, fraud, espionage, and, in other countries, regicide. Law professors say that the criminal must commit the guilty act with a guilty mind for his actions to be a crime. Terrorism goes a step further by asking, “Why did the criminal commit that crime?” It’s the logic of hate crime legislation applied to national security.
The legal and philosophical problems with distinguishing terrorism from other crimes are obvious. If someone intends to kill people and succeeds, why does it matter more if he did it to promote a political cause rather than to get revenge for a personal insult? It’s the same compelling argument against hate crimes existing. The differences don’t matter, but greater punishments for a terroristic motivation incentivize prosecutors and investigators to spend more time trying to find those motivations. Murdering a crowd of people in a church, synagogue, or mosque for religious reasons is not different than murdering them for other, more common criminal motivations. Special terrorism laws shouldn’t exist, but the only downside of such a clean and correct decision is that we would have to rely on popular social definitions of the term that are wrong.
Nowadays, the popular social definition means that every heinous or disturbing crime is labelled terrorism. Former Attorney General William Barr said that Mexican drug cartels are “effectively terrorist organizations” when attempting to justify the use of the US military south of the border to stop drug and migrant smuggling.[9] President Trump called the Black Lives Matter riots of mid-2020 terrorism, and FBI Director Christopher Wray called the January 6, 2021, Capitol riot against the certification of Joe Biden’s 2020 election victory terrorism.[10] Those crimes were all heinous, but smuggling drugs and migrants, looting stores, and rioting on the steps of the Capitol don’t pass the “I know it when I see it” standard. They aren’t the pornography of political violence. British mathematician and risk analyst Gordon Woo coined the term “stochastic terrorism” in 2002, which is when a speaker uses dog whistles and other vague language to inspire terrorists to attack while maintaining plausible deniability.[11] We’re suffering from something even more annoying: A decades-long bout of terrorism inflation.
Avoid the popular modern definition and embrace tradition. Terrorists imagine a different world and want to bring it about through violence. Osama Bin Laden wasn’t motivated by financial gain; he was the son of a wealthy Saudi entrepreneur, and he wanted for nothing material. He and his confederates were motivated to spread Islamist governments throughout the world and kill or convert non-Muslims or Muslims they didn’t think were religious enough. His motivation was religious and ideological. He and Al Qaeda were too weak to accomplish their goals by conquest; they didn’t have armored and infantry divisions, so they engaged in terrorism – the tool of weak and motivated people. Sometimes those weak people really change the world, but mostly not in the ways they intend.
Immigrant Terrorists and Their Victims
Terrorists are weak but not harmless. Their threat rises and falls with their goals, motivations, and competence of terrorists and counterterrorist law enforcement, to say nothing of the role of chance. FBI director Christopher Wray said, “We’ve seen the threat from foreign terrorists rise to a whole ‘nother level after October 7 [Hamas’ 2023 attack on Israel],” in June 2024.[12] Wray’s judgment relies on intelligence reports and other secret government information. Although we don’t have access to the same information as the FBI director, such information isn’t the entire story. Gauging the scale of that threat and whether it’s higher today depends on the base rate of foreign-born terrorism.
The base rate of foreign-born terrorism is the underlying chance of an attack occurring normally without considering any specific information. Looking at the base rate is the starting point of any analysis whether it’s how dangerous a new infectious disease like COVID-19 is likely to be, whether crime has risen, or the chance of being murdered in a terrorist attack. When Wray says that the threat from foreign terrorists has risen to a “whole ‘nother level,” he should explain the new, higher level relative to a lower base rate. He doesn’t mean that, but it’s the implicit way to compare how threats and risks change over time. Thus, we should all start with the base rate and then adjust upward or downward based on new evidence.
The base rate of foreign-born terrorism is startlingly low in the United States. From 1975 through the end of 2024, a total of 3,046 people were murdered in attacks on US soil committed by 237 foreign-born terrorists. About 98 percent of those deaths were the result of the 9/11 attacks – an outlier that is hundreds of times deadlier than the next deadliest foreign-born attack (more on outliers below). The annual chance of being murdered in a terrorist attack committed by a foreign-born terrorist was about 1 in 4.6 million per year. By comparison, the annual chance of being murdered in a normal non-terrorist homicide was just less than about 1 in 14,000 per year. Foreign-born terrorists are responsible for less than one-half of one percent of all the murders that have occurred in the US since 1975.[13] The size of the ship matters more than the motion of the ocean when evaluating the hazard of terrorism.
In an earlier chapter on crime, the homicide conviction and crime rates are presented at normal rates per 100,000 of the population. From 1975 to the end of 2024, the US homicide rate was hundreds of times higher than the chance of being murdered in a normal homicide. Comparing deaths in terrorist attacks to non-terrorist murders is most apt, but it’s also useful to compare terrorism to other everyday risks. More people died in a single month of car accidents in 2024 than in all the attacks by foreign-born terrorists since 1975.[14] These are all different ways of saying that the base rate of foreign-born terrorism is low and you should stop worrying about it so much.
These numbers are not intended to trivialize the real harm caused by terrorists, but there’s no other reasonable way to discuss the hazard of foreign-born terrorists without pointing out how small it is. Even the most frenzied analyst wouldn’t claim the chance of being murdered in a terrorist attack is 100 percent. The most skeptical wouldn’t claim it’s zero. The actual chance is above zero, just not that far above zero. The risks are a lot closer to zero than to certainty.
Lest you think I juiced the numbers above, it’s probably an overcount of terrorists and their victims. They credit foreign-born terrorists for all deaths in attacks carried out by teams of foreign-born and native-born terrorists working together. They also credit everybody convicted for planning an attack, even in those cases where law enforcement or informants working for the FBI concocted the plots and did most of the work. This is more common than you think.
Sami Samir Hassoun told a police source that he wanted to commit a terrorist attack in Chicago. The source introduced Hassoun to two undercover FBI agents whom Hassoun thought were other terrorists. He researched, planned, and attempted an attack after repeatedly asking for money from the FBI agents and arguing that they should employ him.[15] The undercover FBI agents agreed. Hassoun was so delusional that he “settled” for a bombing after setting aside half-baked schemes to unleash a virus on the city and poison its water supply.[16] He fantasized that his bombing would force Mayor Daley out of office so Hassoun could “put some of our guys in.”[17] He never mentions who his guys were, but they probably resided in his imagination like the rest of his fantastical plans. We can safely assume that none of them were good people, even if they were all imaginary.
Hassoun supplied himself with a backpack, and the FBI supplied a fake bomb that he planted before being promptly arrested by the FBI. Hassoun had no idea what he was doing, had no explosives training, and developed several weird plans that rotated between a city-wide coup, mass poisonings, and waging biological warfare. It takes two to tango, and Hassoun had the potential to be dangerous, but he did not concoct a serious terrorist plot. Nobody was in any danger from his non-functional FBI-supplied device except for Hassoun, who was sentenced to 23 years in prison.[18]
The government tracks other plots from inception, so they never posed a hazard. The FBI arrested Pakistan-born Asif Merchant on July 12, 2024, just as he was concluding his plans to hire an assassin to kill then former President Trump in retaliation for an American drone strike that killed Iranian major general Qasem Soleimani in Iraq.[19] Other former government employees were apparently targeted in his murder-for-hire scheme that was tracked by the FBI before he landed, thanks to an informant.[20] The merchant was paid by the Iranian government or related Iranian quasi-governmental agencies and drew his plans on a napkin in his New York City hotel. No other cutlery was implicated in the plot.
Merchant legally entered the United States under an obscure authorization called “parole for significant public benefit.” This form of parole allows a foreigner who wouldn’t normally be able to legally enter to do so if the government thinks there is some big benefit to doing so and they couldn’t enter with another visa. The FBI thought the big public benefit of Merchant being here was to gather evidence to build an ironclad terrorism case against him and to arrest him, which they did.[21] According to FBI sources who talked to Fox News, the bureau’s method of luring terrorist suspects here is not uncommon. Much of this substack series is critical of security agencies chasing their tails and exaggerating small threats, but this is an instance of the FBI behaving responsibly and intelligently to arrest a terrorist without putting anybody at risk.
Merchant isn’t the only example of the Iranian government showing interest in terrorism-for-hire plots. Naji Sharifi Zindashti is an Iranian drug dealer, smuggler, and criminal who contracted a hit on two Iranian defectors living in Maryland. Living in Maryland wasn’t punishment enough, apparently. Over the course of 2020 and 2021, Zindashti negotiated with Canadian Hells Angels Motorcycle Club member Damion Patrick John Ryan to carry out the hit for a $350,000 fee and $20,000 in travel expenses.[22] Ryan then subcontracted the hit to Adam Richard Pearson, a Canadian friend of his living illegally in Minnesota. The plan never went anywhere, and Ryan and Pearson are currently in prison in Canada for unrelated charges. Zindashti never entered the United States. The Iranian government isn’t sending its best hitmen. Not all terrorists are so incompetent, though.
The nineteen 9/11 terrorists committed the deadliest attack in world history, and they escaped prior detection, but nine other potential hijackers were either stopped by immigration authorities or backed out of the plot before it was executed.[23] Mohamed al-Kahtani tried to enter the United States in August 2001 but was turned back by a customs officer, and Zacarias Moussaoui was arrested by immigration agents after suspicious behavior at his Oklahoma flight school in the same month.[24] Eighteen of the real hijackers entered on tourist visas, and one on a student visa.[25] They were smarter than the average terrorist. They weren’t as delusional or crazy as others, and they succeeded in their attacks by bringing down the Twin Towers, hitting the Pentagon, crashing United Flight 93, and murdering 2,979 innocent people. The 9/11 hijackers are the exceptions that prove the rule that most of the terrorists mentioned above couldn’t hit the broad side of a barn if the FBI showed them where the cows are.
Looking at the base rate in the security-enhanced post-9/11 world doesn’t show a vastly more dangerous world riven with terrorism. After 9/11, foreign-born terrorists on US soil murdered 44 people, or two per year on average. The average annual chance of being murdered in such an attack during that time was about 1 in 165 million per year. There were ten years without any deaths in foreign-born attacks on US soil from 2003 to the end of 2012. There were 119 foreign-born terrorists convicted of attacking or planning attacks on US soil during that time – only nine of them murdered anybody in their attacks, and 12 other terrorists injured people without killing them. The pre-9/11 world was mathematically safer, with 14 people murdered in foreign-born terrorist attacks on US soil, with an annual chance of being killed at about 1 in 455 million per year. That was certainly lower than the post-9/11 world, but both are close to the annual chance of being killed by a meteorite. We don’t need a global war on meteorites.
See Something, Say Something
Despite the low base rate of foreign-born terrorism, 9/11 comes to mind when I think of terrorism or read about an attack. I’m not the only one who suffers from their cognitive delusion. Everyone else thinks of 9/11 when terrorism is mentioned too. Politicians and government employees can’t stop talking about it. “Now, 9/11 was 20 years ago. But for us at the FBI, as I know it does for my colleagues here with me, it represents a danger we focus on every day. And make no mistake, the danger is real,” said FBI Director Christopher Wray in September 2021.[26] Representative Bennie Johnson (D-MS) said, “We recognize the success we have had in preventing another 9/11-style attack, but are sobered by the challenges posed by long-standing and emerging homeland security threats.”[27] The House Judiciary Committee mentioned 9/11 multiple times in its report on foreign-born terrorists crossing the U.S.-Mexico border, to both remind readers about those deadly attacks and because no deadly terrorists have crossed that border (more on that in a following chapter).[28]
You can’t watch a Congressional hearing about terrorism without elected officials or witnesses invoking 9/11 to prove just about any point.[29] Even outside of the Beltway, nary a comment about terrorism is made without reference to or thought of 9/11. Those attacks changed the world in myriad ways, but their greatest lingering psychological effect was inflating perceptions of the risks and harms of terrorism.
We all saw 9/11. We can’t stop thinking or talking about it when terrorism comes up, but it shouldn’t be that way. 9/11 was the deadliest, most destructive, and biggest terrorist attack in world history. The next deadliest attack was one-ninth as murderous. Hamas’ attack on Israel on October 7, 2023, was brutal, targeted civilians, and was motivated by an attempt to change the world. Hamas’ attack was not normal criminal behavior, but it wasn’t a terrorist attack under the accepted definition because the government of Gaza committed it. That doesn’t diminish the brutality of the 10/7 attack nor the seriousness of Hamas’ goals because we must judge the actions of governments by the same standards that we apply to everybody else, but it’s the reason why this chapter doesn’t compare 9/11 to Hamas’ attack. The 10/7 attack has more in common with the Japanese attack on Pearl Harbor on December 7, 1941, than with 9/11.
The scale of the 9/11 attacks is so much larger than other terrorist attacks that it can only be explained with statistics. Almost 98 percent of all people killed in terrorist attacks committed by foreign-born attackers on US soil since 1975 were killed on 9/11. For every 45 people murdered by terrorists on 9/11, 1 person was killed in another attack committed by a foreign-born terrorist. The next deadliest attack committed by a foreign-born terrorist was the 2015 San Bernardino shooting committed by Pakistani-born Tashfeen Malik and her American-born husband Syed Farook. For every person who was murdered in San Bernardino, 213 were murdered on 9/11. The 9/11 attacks dominate the study of terrorism because the scale of death and destruction is so much greater than anything else. But that also means that the 9/11 attacks are a statistical outlier that we shouldn’t use as our terrorism yardstick.
An outlier is a significantly more extreme event than the norm because it’s much bigger or smaller. In terms of terrorism, it means that 9/11 was much deadlier and more destructive than other terrorist attacks. Statisticians measure outliers by looking at the standard deviation, which tells you how spread out the number of murders across terrorist attacks is. The further away from the average a terrorist attack is, as measured by the number of standard deviations, the more likely it is to be an outlier. The more an attack’s death toll exceeds that typical range, the more of an outlier it is. However, it’s impossible to use those normal statistics here because three-quarters of the 237 foreign-born terrorists since 1975 didn’t kill anybody in their attacks. Yes, most foreign-born terrorists didn’t murder anyone in their attacks. And many failed to even commit attacks because they were arrested while plotting. It’s not the keystone cops versus the gang that couldn’t shoot straight; it’s the gang that couldn’t shoot straight because it hardly tries.
Even reorganizing the data by the deadliness of attacks and intended attacks rather than murders committed by individual terrorists shows that 83 percent of attacks committed by foreign-born terrorists didn’t result in any murders. Standard deviations are only meaningful in normally distributed data, a so-called bell curve, and deaths in terrorist attacks are not normally distributed because so many attacks have a death count of zero. The data on the deaths in terrorist attacks are “skewed,” which means that when you plot the number of deaths in terrorist attacks on a graph, most of them are on one side – zero in this case.[30] Therefore, standard deviations are just not useful here.
Still, there are other ways to show that 9/11 is an outlier. The number of deaths at the 90th percentile, which is for an attack that is deadlier than 90 percent of all other terrorist attacks, is a good way. The 90th percentile deadliest attack by a foreign-born terrorist is one, and rises to two when all native-born attacks are included. The 99th percentile deadliness for all attacks is 13 deaths. The deadliness of 9/11 is 229 times deadlier than terrorist attacks at the 99th percentile of deadliness.
Nassim Nicholas Taleb popularized the term black swan to describe events with three defining characteristics.[31] First, they are outside the realm of regular expectations and nothing in the past can convincingly point to their possibility. Second, they have a profound and extreme impact. Third, people respond to black swans by trying to explain that they were inevitable in hindsight, but this post-hoc analysis doesn’t produce any models that help predict future black swans. Taleb doesn’t have a hard and fast statistical rule about how outside of the realm of regular expectations events must be to be black swans, but 9/11 meets every definition.[32]
The 9/11 attacks are so unlike any other attack that there is no good reason to think of them when you hear about terrorism, but you and I both do because scale is more memorable and easily recallable than other details. And most people don’t know as much about terrorism as you do after reading the previous paragraphs. The hoi polloi neglect the statistics, but you don’t, right? At least not anymore, you don’t, but don’t beat yourself up over your past mistakes. Thinking about 9/11 every time a terrorist attack happens is the result of a universal human brain defect called availability bias.
The bigger and more dramatic an event, the more memorable it becomes. If it was anything, 9/11 was big, dramatic, and, hence, memorable. When another terrorist attack happens or terrorism is mentioned in passing, we immediately think of 9/11, even though they have little in common. Since terrorism and 9/11 are linked in our brains, a new terrorist attack also triggers a reaction called mortality salience. The core idea is that we cling to our own cultural beliefs when confronted with events that remind us of death, which is terrifying, by embracing patriotism, being more willing to punish moral transgressors, boosting heroes, and favoring ingroups over outgroups. In other words, people confronted by terrorism are likely to become more xenophobic and distrustful of immigrants and other foreigners.[33] Availability bias makes us overestimate the risks of terrorism and mortality salience boosts our xenophobia toward foreigners or immigrants.
Terrorism experts are a panicky lot who exaggerate the risks, but the most levelheaded among them tend to call terror attacks a “low probability and high-cost event.” It’s certainly rare, so terrorism is low probability, but only somebody who focuses on the 9/11 attacks could call terrorism “high-cost.” Three-quarters of terrorists don’t murder anybody in their attacks, which is one reason why 9/11 dominates the conversation. Terrorism is most expensive to the victims, but much of the cost we impose on ourselves through counter terrorism laws, restrictions on civil liberties, more wars that we lose, and immigration restrictions. The monetary cost of counterterrorism alone was $2.8 trillion through 2017, excluding the cost of reducing immigration or curtailing civil liberties.[34]
Was that worth it? It’s difficult to compare whether monetary costs to save a life are worth it, but economists have found a plausible way to do so that is intellectually sound and offends almost everybody: the value of statistical life. You may be forgiven for thinking this is a new form of life cooked up by social scientists in a laboratory, but the intuition behind it makes sense.
The value of statistical life is based on one simple assumption: Nobody places an infinite value on their life. It considers the tradeoff rate between fatality risk and money for a person. Everyone voluntarily makes decisions that increase their chance of dying, like driving in an automobile, and weighs the tradeoffs that balance those potential costs with expected benefits, like getting to work faster. Economists take these insights to see how much people value their own lives based on their actions and then compare them to the cost of extra safety intended to reduce death. Suppose the cost of the additional safety is more than the value of the lives saved. In that case, the extra safety is a waste at best, likely resulting in more deaths at worst because the wasted safety resources could be used elsewhere to save more lives.
Analyzing public policy actions through this lens is common in health economics, labor economics, legal cases, and national security.[35] The statistical life is valued in dollars because it’s easier to gauge tradeoffs with dollars, which are all the same, than with other units that are not the same. Assuming a value of $15 million per life, which is on the high side, at $2.8 trillion, counterterrorism spending would only be justified if it had saved nearly 200,000 lives. In reality, just 41 people were murdered in foreign-born terrorist attacks during those years.[36] Counterterrorism spending could have saved that many lives. It is logically possible, but it is even less likely than Saddam Hussein giving weapons of mass destruction to terrorists after 9/11.
The number of lives that would have had to have been saved by counterterrorism to justify the cost is so high that we can safely dismiss the argument that the post-9/11 counterterrorism spending was worth it. A counterargument could be that the counterterrorism money spent probably saved some lives by preventing a few terrorist attacks. That may be the case, and we’ll never know for sure, but many more lives would have been saved if the money hadn’t been spent at all because the spending itself killed people. The evidence for this is pretty unassailable.
The federal government created the Transportation Security Administration (TSA) after 9/11 to prevent hijackers from boarding planes. We’ve all mostly stood in their lines and endured our humiliating roles as bit players in security theater by being poked, prodded, scanned, and harassed. And we have to do it all with a serious look on our faces while we take off our shoes and throw away water bottles and tubes of toothpaste because we’ll be banned from flying if we don’t. The TSA agents and their political bosses bear the most blame, but if you laugh at the absurdities in the airport security line, then you’ll earn jingoistic glares from your fellow travelers and learn why the system that makes you take off your shoes in public is so enduring.
But some people didn’t like being poked, prodded, or scanned, and others were so scared of flying because of the fear of terrorism that they chose to drive instead of flying.[37] Driving on American roads is far more dangerous than flying. Many analysts have looked at the increase in miles driven as a response to 9/11 and to avoid the TSA and found that about 500 more people a year die in car accidents to avoid the airport hassle. If half of those chose to drive over flying because they wanted to avoid the TSA, then the TSA caused about 4,000 deaths from 2002 to 2017, more than those who died on 9/11. TSA spending is just a small fraction of all counterterrorism spending, but likely the portion with the deadliest domestic consequences. By pushing people to drive instead of fly, TSA security theater probably caused thousands of extra road deaths, more than all terrorist attacks since 1975 combined.
It’s extremely unlikely that counterterrorism spending saved enough lives to be justified and much more likely that it killed more people than it saved, but this doesn’t even consider that the money could have been spent to save lives through other ways, such as better criminal deterrence, improving road safety, subsidizing EpiPens, or paying people to live healthier lifestyles. This section isn’t arguing that the government should spend more money on those goals, but merely that counterterrorism spending is an exceedingly poor way to spend money if the goal is to save lives. Another cost is the reduction in legal immigration and tourism in response to 9/11, which has cost the US economy trillions of dollars in lost economic output. There are millions fewer immigrants in the US as a result of reductions in legal immigration and travel since 9/11, imposing a cost on would-be Americans, current Americans, and the rest of the world.[38] American society and government changed in response to the 9/11 attacks and the fear of future potential terror attacks.
Most terrorists are insane and cognitively deficient (stupid). Judd Sanson is an extreme example of an insane, stupid person who may have been planning a terrorist attack. Sanson is a native-born American who was pulled over in New York while driving a car with forged or altered license plates. Police then found multiple weapons in his car, including a pistol, body armor, and an expandable baton with the phrase “God Forgive Me” written in Arabic. Investigators aren’t sure whether Sanson was planning a terrorist attack, but he fits the pattern. His neighbors said that Sanson was mentally ill and thought he was a ninja.[39] He must’ve skipped the “how to be stealthy” lesson in ninja school.
Wise people have said that we shouldn’t alter our society in response to terrorism. Former American Bar Association President William Falsgraf said, “If we do, the terrorists have won.”[40] Judging by how much we have changed our laws, started wars, reshaped society, bumped up the levels of fear in response to terrorism, and spent trillions of dollars in ways that likely killed thousands of Americans without saving many lives, it’s hard to argue that the terrorists haven’t already won.
[1] Shane Harris and Stuart Taylor, “Homeland Security chief looks back, and forward,” Government Executive, March 17, 2008.
[2] “Part Two: Foreign Policy | Barack Obama: The Vox Conversation,” Vox, January 2015.
[3] “Jacobellis V. Ohio 378 US 184 (1964),” ACLU of Ohio, latest update June 22, 1964.
[4] “Administration Statements on Iraqi - Al Qaeda Links,” Federation of American Scientists, 2005.
[5] “Administration Statements on Iraqi - Al Qaeda Links,” Federation of American Scientists, 2005.
[6] “Administration Statements on Iraqi - Al Qaeda Links,” Federation of American Scientists, 2005.
[7] “Administration Statements on Iraqi - Al Qaeda Links,” Federation of American Scientists, 2005.
[8] Robert C. Allen, Mattia C. Bertazzini, and Leander Heldring, “The Economic Origins of Government,” American Economic Review 113, no. 10 (October 2023): 2507–45.
[9] Tim Meads, “Bill Barr: We Need To Treat Mexican Drug Cartels ‘Like ISIS’,” The Daily Wire, July 23, 2022.
[10] Donald Trump, “Statement by the President,” Trump White House Archives, June 1, 2020; Tim Meads, “Bill Barr: We Need To Treat Mexican Drug Cartels ‘Like ISIS’,” The Daily Wire, July 23, 2022.
[11] “Stochastic terrorism,” Wikipedia, last modified August 23, 2025.
[12] Christopher A. Wray, “Director Wray’s Opening Statement to the Senate Appropriations Committee Subcommittee on Commerce, Justice, Science, and Related Agencies,” Federal Bureau of Investigation News, June 4, 2024.
[13] Alex Nowrasteh, “Terrorism and Immigration: 50 Years of Foreign-Born Terrorism on US Soil, 1975–2024,” Cato Institute Policy Analysis no. 991, March 10, 2025.
[14] “NHTSA Estimates Traffic Fatalities Continued to Decline in the First Half of 2023,” National Highway Traffic Safety Administration, September 28, 2023.
[15] “United States v. Hassoun,” Criminal Complaint, US District Court for the Northern District of Illinois, Eastern Division, filed September 20, 2010, affidavit by Special Agent Samuel Hartman, sworn before US Magistrate Judge Susan Cox, Investigative Project on Terrorism.
[16] “United States v. Hassoun,” Criminal Complaint, US District Court for the Northern District of Illinois, Eastern Division, filed September 20, 2010, affidavit by Special Agent Samuel Hartman, sworn before US Magistrate Judge Susan Cox, Investigative Project on Terrorism.
[17] “United States v. Hassoun,” Criminal Complaint, US District Court for the Northern District of Illinois, Eastern Division, filed September 20, 2010, affidavit by Special Agent Samuel Hartman, sworn before US Magistrate Judge Susan Cox, Investigative Project on Terrorism.
[18] “Chicago Man Sentenced to 23 Years in Prison for Attempted Bombing on Crowded Street Near Wrigley Field in September 2010,” Federal Bureau of Investigation Chicago Division, May 30, 2013.
[19] Robert Legare, Nicole Sganga, and Andres Triay, “U.S. charges Pakistani with alleged Iran ties in murder-for-hire plot against Trump, U.S. officials,” CBS News, August 7, 2024.
[20] “United States v. Asif Merchant,” Complaint and Affidavit in Support of Application for Arrest Warrant, Docket No. F. #2024R00922, United States District Court, Eastern District of New York; Louis Casiano, Bill Melugin, and David Spunt, “Pakistani man accused of plotting political assassination admitted into US via immigration parole: sources,” Fox News, August 7, 2024.
[21] Louis Casiano, Bill Melugin, and David Spunt, “Pakistani man accused of plotting political assassination admitted into US via immigration parole: sources,” Fox News, August 7, 2024.
[22] Robert Legare, “Justice Dept indicts 3 in international murder-for-hire plot targeting Iranian dissident living in Maryland,” CBS News, January 29, 2024; “United States v. Naji Sharifi Zindashti, Damion Patrick John Ryan, and Adam Richard Pearson,” Indictment, United States District Court, District of Minnesota, filed December 13, 2023.
[23] National Commission on Terrorist Attacks Upon the United States, The 9/11 Commission Report (Washington, DC: US Government Printing Office, 2004), p. 235.
[24] National Commission on Terrorist Attacks Upon the United States, The 9/11 Commission Report (Washington, DC: US Government Printing Office, 2004), pp. 11, 247.
[25] Alex Nowrasteh, “Terrorism and Immigration: A Risk Analysis, 1975–2023,” Cato Institute Policy Analysis no. 972, April 9, 2024.
[26] Christopher Wray, “Threats to the Homeland: Evaluating the Landscape 20 Years After 9/11,” Statement before the Senate Homeland Security and Governmental Affairs Committee, Washington, DC, September 21, 2021.
[27] US Congress House Committee on Homeland Security, “Hearing: Worldwide Threats to the Homeland: 20 Years After 9/11,” 117th Cong., 1st sess., September 22, 2021.
[28] US House Committee on the Judiciary and Subcommittee on Immigration Integrity, Security, and Enforcement, “Terror at Our Door: How the Biden-Harris Administration’s Open-Borders Policies Undermine National Security and Endanger Americans,” Interim Staff Report, August 5, 2024.
[29] US House Judiciary Committee, Subcommittee on Immigration Integrity, Security, and Enforcement, “Hearing: Terrorist Entry Through the Southwest Border,” 118th Cong., 1st. sess., September 14, 2023.
[30] The interquartile range is 0, so it’s impossible to use that to calculate outliers.
[31] Nassim Nicholas Taleb, The Black Swan: The Impact of the Highly Improbable (New York: Random House, 2010).
[32] Nassim Nicholas Taleb, The Black Swan: The Impact of the Highly Improbable (New York: Random House, 2010).
[33] Hoi-Ting Leung, Peter K. H. Chew, and Nerina J. Caltabiano, “Mortality Salience Effects of Critical Incidents - A Systematic Literature Review and Research Agenda,” OMEGA—Journal of Death and Dying 90, no. 1 (November 2024): 73–119.
[34] Stimson Center, “Counterterrorism Spending: Protecting America while Promoting Efficiencies and Accountability,” May 16, 2018.
[35] Alex Nowrasteh, “Espionage, Espionage-Related Crimes, and Immigration: A Risk Analysis, 1990–2019,” Cato Institute Policy Analysis no. 909, February 9, 2021.
[36] Alex Nowrasteh, “Terrorism and Immigration: A Risk Analysis, 1975–2022,” Cato Institute Policy Analysis no. 958, August 22, 2023; Alex Nowrasteh, “Counterterrorism Spending,” Cato at Liberty (blog), May 25, 2018.
[37] Bruce Schneier, “Excess Automobile Deaths as a Result of 9/11,” Schneier on Security (blog), September 9, 2013.
[38] David J. Bier, “The 9/11 Legacy for Immigration,” The Independent Review: A Journal of Political Economy 26, no. 2 (Fall 2021): 205–224.
[39] Kala Rama and Erin Pflaumer. “Baton with ‘God Forgive Me’ written in Arabic found in ghost car in Queens: sources,” PIX11, June 13, 2024; John Miller, Michelle Watson, and Nic F. Anderson, “Man arrested in New York City with a gun, 8 loaded magazines, an NYPD vest and other weapons, police say,” CNN, June 13, 2024.
[40] Jeanne B. Clarizio and Arthur Rovine, “At Issue: Will anti-terrorism become the McCarthyism of the 1980s?“ ABA Journal 72, no. 1 (January 1, 1986): 36, 38, 40.