The terrorist attacks of September 11, 2001—along with two long wars in Afghanistan and Iraq—forever shattered Americans' sense of safety and security, particularly for those living in cities like New York, Washington, DC, and Boston. So, what have we learned in the generation since about the impact 9/11 has had on us, as well as how terrorists think? Boston University professor Jessica Stern, PhD '92, a global expert on counterterrorism and perpetrator psychology, talks about the trauma of terrorism and how an understanding of it can help us prevent public violence.
Before we get into the nuts and bolts of counterterrorism and your work, I wonder if you could talk about what you remember from September 11, 2001: where you were, what you were doing, and what happened afterward.
When the first plane hit the tower, I was at home, and I got a call from NPR. They were already thinking this might be more than an accident. I remember I was in my sweatpants, and they asked me to come in right away. I ended up spending the day at NPR, which meant that I missed having to watch television, as a lot of people were doing. I know you're curious about the impact of the trauma. It turns out that watching television that day was a risk factor for trauma.
Soon afterward, I was getting many calls from the media because there was a very small group of us working on terrorism—a small group all around the world. It just wasn't a popular topic. I couldn't answer all the calls that were coming in, so the dean's office took over my phone. I remember being so exhausted, even though I realized in retrospect that I was quite dissociated that day, as I think many people were. In those weeks, I remember lying on the floor in the middle of the day. I was so exhausted from all the queries, but also from the trauma that I wasn't really feeling.
My (Harvard Kennedy School) dean at the time, the late Joe Nye, [PhD ’64] asked me to cancel my classes, go to New York, and appear on television. He thought it was a public service. He sent one of our publicists at the Kennedy School with me. She is still traumatized by that experience because we flew to New York, and there was almost no one on the plane. There was almost no one on the street in New York. It was a couple of days after planes had begun flying again, but it was a surreal experience. That's what I remember.
Not to get into the policy responses or any of that, but do you remember when it became clear that it was, in fact, a terrorist attack? Do you remember your top-line thought about what the future might hold?
I remember thinking, “We have lived through the safest and happiest years of our lives as a nation, and things are going to go downhill.” That was the thought that came to me.
You mentioned that, at the time NPR called you, there was only a small group of people working on terrorism. You had served in the Clinton administration on the National Security Council staff in the mid-1990s. Had you started working on terrorism then? How did you come to the field?
I had studied chemistry as an undergraduate. In fact, I was about to pursue my PhD in chemistry when I learned about a program at MIT on technology policy. Then I did my PhD with Ash Carter. My work was pretty technical, so I was working on the weapons that terrorists might use. I did a postdoc at Lawrence Livermore National Laboratory on weapons-of-mass-destruction-related intelligence. But I was curious about terrorism and about the perpetrators.
Even though I wasn't trained to work on perpetrators—I didn't have a PhD in psychology; I had one in public policy—I started talking to terrorists. I went to a couple of anthropologists and asked, “Can you train me to conduct this kind of ethnographic interview?” They said, “Well, you're doing it. It's working. We don't really know how to do that.” I kept doing it.
I started in a trailer park in Texas with a white supremacist, and then I spent a lot of time in Pakistan. I met with a founder and leaders of Hamas. I met with leaders of Hezbollah. But the place I really got to know was Pakistan. In fact, I spoke with one of the five signatories of bin Laden's 1998 fatwa, which urged Muslims all over the world to target American civilians as well as military personnel. I knew that man. His fighters said they were al-Qaeda when they were in Afghanistan and Harkat-ul-Mujahideen when they were in Pakistan. I got to know the jihadists in Pakistan quite well.
[On 9/11] I remember thinking, “We have lived through the safest and happiest years of our lives as a nation, and things are going to go downhill.”
I'd love it if you could talk more about the dichotomy between the trauma's impact on the leadership—the people making the decisions—and its impact on the American public.
Three to five days after the attack, about 90 percent of Americans showed some symptoms of post-traumatic stress—not post-traumatic stress disorder, but stress. Most Americans recovered very quickly. The people who were very close to the towers, and certainly the first responders, were traumatized and had symptoms of post-traumatic stress disorder for a longer period.
I also think it's important for us to recognize that our military personnel who had to fight the wars on terrorism were extremely traumatized. About 7,000 soldiers died in the wars, and about 30,000 died by suicide. This is one of the major impacts of war: It's very traumatizing to the soldiers.
Obviously, we also killed many people—nearly a million, according to Brown University's Costs of War project—and many more died as a result of the wars because public health infrastructure was harmed and people went hungry. These wars were incredibly tragic and costly, not only for the victims but also for the soldiers.
You made a distinction between post-traumatic stress and post-traumatic stress disorder. Could you unpack that? What's the difference?
After an event like 9/11, almost everybody is going to have symptoms of heightened stress, and everybody processes it differently. Those who were very close and those who watched television—some people were watching television all day for 12 hours—were much more susceptible to experiencing symptoms that did not go away for a longer period. It could be nightmares. It could be images coming into your mind. It could be avoiding certain places or activities. For a soldier, it could be seeing trash on the street and imagining that somebody is hiding there, about to shoot you. It could be the sound of fireworks being very debilitating. Post-traumatic stress disorder is when those symptoms that you might feel in the first few days or for a week plague you for months and often years afterward.
I'm going to ask you shortly about your concerns regarding transnational versus domestic terrorism. But since we're talking about psychology and trauma, what do we understand today about terrorism—particularly the psychology of perpetrators and the role of religion—that we didn't understand 25 years ago?
When I first started studying terrorism, the widely accepted idea was that terrorists are violent intellectuals, that they're motivated by an ideology, and that they're fanatics. I bought into that until I started talking to terrorists. The terrorists themselves taught me that I was wrong and that this understanding of terrorism was wrong.
In war zones, or where governments are using terrorists as part of their military posture, people become terrorists not only because of ideology but also because terrorism can be a job. They may choose one terrorist group over another because it pays better. People joined ISIS rather than al-Nusra because they essentially got a better salary, better health insurance, and better life insurance. They made decisions partly as a result of those ordinary factors. They also joined because of their social networks. These are all pull factors.
There are also very important personal push factors. People become terrorists because they may have been traumatized. I heard stories about people joining Pakistani jihadi groups because they had seen someone raped by Indian military personnel. They had witnessed something in their own lives. I think the ideology of hating the other resonates particularly with people who have had a personal experience. There are many pull factors; ideology is just one. Religious ideology at that time was powerful for some people.
Looking at domestic terrorism today, a nonprofit that works with radicalized youth gave me 7,000 pages of intervention notes about 65 radicalized young people. We took a year to deidentify and then code the data, which took a couple of years. All of this can now be done very quickly with AI. We found that about 80 percent reported extreme mental distress or, in many cases, mental illness, and 43 percent reported having been bullied. Those are examples of push factors. In the United States today, those personal push factors are very important, and ideology has begun to pale in comparison.
I want to ask you more about domestic terrorism and your concerns about it. But you mentioned that you had bought into a certain notion of who terrorists were and why they did it: that they were intellectuals who had been radicalized. Then you started talking to terrorists. You spoke with leaders of Hamas and Hezbollah, and you wrote a book about ISIS. Do you have a story about a conversation with one of those people that was an aha moment for you, when a lightbulb went on, and you realized it was very different?
I have a number of those stories. The one that I think is most powerful for me concerns the leader of Harkat-ul-Mujahideen. It took me a few years to interview him. His name is Fazlur Rahman Khalil. Why did I finally get to interview him? I would say because Pakistan's intelligence agency, the ISI, wanted me to, but it must have taken a while to decide that.
I went to see him in his offices, and I kept thinking, “This is jihadi theater.” There were fighters wearing vests in which they carried bullets. They served me tea in a dirty cup with horrible buffalo milk. Fazlur Rahman Khalil kept me waiting, the way a CEO might keep someone waiting to establish his importance. At first, he gave me the party line about how they weren't connected with al-Qaeda, even though some of his personnel had been killed in Khost when we bombed. I let him go on voicing the ideology that I knew by heart and could have recited to him.
Somehow, it came into my mind to ask whether he was married. Clearly, he wasn't prepared for this question. I have to assume the ISI had briefed him on how to deal with me, but they hadn't briefed him on how to answer that question. He told me very happily and proudly that he had just married a second wife. I asked him about her and where she was. She was in his home nearby. I asked if I could meet her. He definitely wasn't prepared, but he said yes.
We walked down the street—this group of armed jihadis and me—to his home, which was a giant mansion. I met his absolutely gorgeous Saudi wife, who spoke impeccable English. She served me ice-cold Coca-Cola and beautiful mangoes. He had met her on a fundraising mission in Saudi Arabia. I had met a number of his fighters, one of whom had figured out that his boss was getting rich from being a major jihadist and had left the organization. That's when it really came home to me that jihad can, in certain situations, be a job. I don't think Islamist ideology was what motivated him.
To return to the question of transnational versus domestic terrorism, where are the new threats coming from? Which concerns you more? Iran is a notorious state sponsor of terrorism, and we're at war with it now. Of course, we've arguably been in a state of war with Iran in one way or another for a long time. But you've mentioned 7,000 pages of information about domestic extremists. Which concerns you more, and where, in particular, do you see the threats coming from?
Since 9/11, we've made many changes in our counterterrorism posture. We established the Transportation Security Administration. All luggage is screened when people fly. We have air marshals. The pilot sits behind a locked door. Planes are still very attractive targets. There have been many failed attempts to take down planes. There was the shoe bomber, the liquid bomb plot, and an attempt to take down a cargo plane. We've made it very hard for a terrorist organization to repeat 9/11. In fact, all the terrorist attacks since 9/11 that have occurred in the United States have been carried out by US citizens or legal US residents, except one. Just one was carried out by a foreign terrorist. We've made a lot of progress.
Regarding Iran, they're carrying out cyberattacks. For whatever reason, they've decided that is the expedient type of terrorism to carry out against us. But Americans have turned against one another. We saw, for example, the targeting of Melissa Hortman and her husband and the targeting of Charlie Kirk. We're seeing a mix of hard left and hard right.
Sometimes it's hard to figure out, and the terrorists themselves don't seem to know what their ideology is. We see so-called ecofascists. That would be a combination of ecoterrorism, which we used to associate with the hard left, and fascism or white supremacy, which we associate with the hard right. We also see a new type of terrorism that the FBI calls nihilistic violent extremism, in which there is not even a pretense that the goal is to create a new world. It's all about destruction. That's how terrorism has evolved. I think the terrorism that most worries the FBI today is nihilistic violent extremism.
We've made it very hard for a terrorist organization to repeat 9/11. In fact, all the terrorist attacks since 9/11 that have occurred in the United States have been carried out by US citizens or legal US residents, except one. Just one was carried out by a foreign terrorist. We've made a lot of progress.
You're bringing me back to a basic question that I wish I had asked at the outset: What is terrorism supposed to do? What is its goal? From what you've said in describing all these different kinds of terrorism and actors, it sounds as though the goals could range from a policy objective—such as getting a country's troops out of another country—to simply wanting to burn it all down.
What's interesting is that the terrorist groups that seem to survive are those that can keep changing their mission. A sticky mission is risky. The question is: Is the mission marketing, or is it what the terrorists want? Do they want to change the world, tear it down, or change themselves? I think some people are drawn to terrorism more because they want to change themselves.
The kind of terrorists we see today in nihilistic violent extremism are often young people interested in a kind of sadism and status. They achieve status by harming more people. They're not trying to change the world at all. As I said, I was initially completely persuaded that terrorism was all about the new world that terrorists wanted to build. Over time, talking to terrorists, I've realized that this is just one of many things they're trying to do.
I understand that you have a forthcoming book about public violence. What have you—and we—learned about the best ways to keep these kinds of catastrophes from happening?
For a long time, the CDC (US Centers for Disease Control and Prevention) has developed a public health approach to preventing all kinds of violence, identifying risk factors and protective factors. Recently, the Department of Homeland Security and the CDC have come to realize that the risk factors for domestic terrorism—which mostly involves lone actors—and other types of violence are shared, and that we might be able to intervene before an attack takes place.
We now know that most lethal terrorism in the United States involves guns. Obviously, our gun policy is part of the problem. One intervention that seems to be effective is persuading people to secure their guns. That's effective against suicide as well as violence. But we've also realized that, in more than 80 percent of lone-actor attacks—whether it's something that might be called a mass shooting that seems not to have an ideology or lone-actor terrorism—there is leakage. Somebody is going to know about the person's ideology or even a full plan, and it's possible to intervene. In a number of efforts around the country, we are providing some kind of therapeutic intervention while the police go into the home and make sure guns are fully secured or, in cases involving mental illness, temporarily removed.
[When there is a terrorist attack] I think it's very important that policymakers conduct this kind of risk-trade-off analysis, in which we try to think about the long-term impact of interventions. We compare the new dangers that our intervention will introduce with those of a smaller intervention . . . and make sure that we're not falling prey to action bias. For me, on the 25th anniversary of 9/11, that's the lesson I would like to see us finally take on board.
When you say “therapeutic intervention,” what do you mean?
One of the projects I'm working on now at the Harvard T.H. Chan School of Public Health involves a team run by Marcia Testa. We are evaluating an effort in Michigan. It's a kind of experiment in schools: When a child is identified as a person of concern—a person who may be at risk of violence—can we provide mentorship? More than 100 children have been identified in just one part of Michigan in the last three or four years. A mentor meets with the child three times a week. The person is thoroughly evaluated at a hub at Michigan State University, where a child psychiatrist determines exactly what that person needs. As I mentioned, there is a lot of mental distress in the population—not only children who might hurt someone at school, but those who may commit workplace violence or any kind of public violence. Often, people need help, and it's possible to give them the help they need. It's amazing how successful this program has been.
It sounds like something we could use at the national level. Finally, we've talked a lot about the lessons of 9/11 and what the country did in response, both domestically and in foreign policy. But what lessons of September 11 are you concerned that we've failed to learn?
For me, the most important lesson of our reaction to 9/11 relates to action bias and to how national leaders respond to trauma. This will happen again. There will be something really frightening, whether it's the fear of Iran's nuclear weapons program or its growing cyberattack capabilities. I think it's very important that policymakers conduct this kind of risk-trade-off analysis, in which we try to think about the long-term impact of interventions. We compare the new dangers that our intervention will introduce with those of a smaller intervention, compare them very carefully, and make sure that we're not falling prey to action bias. For me, on the 25th anniversary of 9/11, that's the lesson I would like to see us finally take on board.
