Since the San Bernardino shootings, it's become increasingly clear that the shooters — Syed Farook and Tashfeen Malik — had been radicalized by jihadist propaganda, and Malik reportedly pledged allegiance to ISIS leader Abu Bakr al-Baghdadi on Facebook. So far it's unclear if they had direction from ISIS proper; it appears more likely that they decided to attack on their own after being exposed to ISIS's message. "We have no evidence that the killers were directed by a terrorist organization overseas," President Obama said in a Sunday address, "but it is clear that the two of them had gone down the dark path of radicalization."
If it does turn out that the San Bernardino shooters were in fact "lone wolves" with no direct connection to the ISIS leadership, this raises an obvious question: How worried should Americans be about this kind of "lone wolf" attack happening again?
To answer that, I called up Peter Neumann, a professor at King's College London and the director of the International Centre for the Study of Radicalisation. As the name of his organization might suggest, Neumann is one of the world's leading experts on how people in the West come to commit violence in the name of groups like ISIS — so it's worth listening to what he has to say.
His basic message might be surprising coming from a professional counterterrorism analyst: The risks to America from ISIS-inspired lone wolves are fairly low. And it's important to recognize the limited threat from lone wolves for what it is.
"Terror is a sensation that depends on you believing that there is more to it than there is — that there is a whole movement behind these people in San Bernardino," Neumann explained. "And the reality is, of course, there isn't."
Why the lone wolf risk is lower than you think
The starting point for understanding this, Neumann suggests, is to look at the differences between the United States and Europe. In Europe, there's a large population of disenfranchised, excluded Muslims. A small percentage of them might be interested in traveling to Syria and Iraq to train with ISIS and plan attacks back home — but it's a much larger percentage than among American Muslims.
"The number of foreign fighters from the US in Syria and Iraq is quite low — most people would say the number is around 100," Neumann says. "Belgium has a population of 11 million, which is — let me get the math right — is about 3 percent of the population of America. Belgium has 500 foreign fighters."
As a result, ISIS would have a hard time pulling off something like November's massive terrorist attacks in Paris in the US. That, Neumann explains, was a complex attack that involved both local radicalization and training the attackers in ISIS-held territory. Without "the structure that clearly exists in Europe," Neumann says, referring to ISIS's ability to funnel trained operatives into the European Union, "all that ISIS can hope for is to incite attacks in America."
In practice, that means using social media and online propaganda to encourage would-be attackers in the US. But according to Neumann's research, that's a surprisingly ineffective way to recruit terrorists. It turns out that many people the media hyped as "lone wolves" actually had a long history of involvement in radical movements, and the internet was only a contributing factor rather than the reason for their radicalization.
"Compared to the hype that there is about the internet," Neumann says, the number of "people who were purely and exclusively radicalized through the internet ... is fairly small."
Moreover, it may be that many of these people are simply latching onto extremism when they're really motivated to violence by other factors. A survey of 119 lone wolf terrorists by the University of London's Paul Gill found that many of these attackers were socially isolated or mentally ill.
"This is not true for terrorists as a whole," Neumann says. In his own research, he is a big proponent of the idea that ideology can motivate people to join terrorist groups. But Gill's study suggests that lone wolves are less motivated by ideology than terrorists who actually join groups. They might, it seems, be fueled more by personal demons.
Bottom line? The risk of online radicalization inspiring a lot more attacks in the United States is fairly low — and even if a future attack does happen, there's a decent chance it might be a "normal" mass shooting, resulting principally from personal problems, even if the attacker claims to be acting in ISIS's name.
That doesn't mean attacks will never happen in the future — according to Neumann, the opposite is more likely to be true. Rather, it's important for us to keep the real scale of threat in context.
"There is a risk that this might happen again," Neumann emphasizes. "But I think it is important to understand that this is a fairly isolated phenomenon, and just because this happened in San Bernardino does not necessarily mean this happens all the time."
Beating lone wolves means not fearing them
Yet despite the fact that these lone wolf attacks seem to be so rare, ISIS is devoting real resources to inspiring them. I asked Neumann why.
His answer was very simple: to start a panic and turn Americans against themselves.
"What ISIS understands, more than al-Qaeda before, is that even fairly limited acts of violence can be very terrorizing," he explains. "Terrorism is not necessarily about the number of people you kill; it's about the terror you create."
Suppose, Neumann proposed, ISIS somehow managed to behead someone in the middle of Times Square. Objectively, that wouldn't pose anything like a huge threat to Americans: The attack would only kill one person, and the odds that the attacker would get away to strike again are astronomically low.
But the psychological effect of the attack would be enormous. "That would create an enormous anxiety and sense of terror among the American people," Neumann says. "That could very easily be done by one person, without planning, without preparation. In terms of bang for the buck — if you'll excuse me for using that word — lone actors have the capacity to create a lot of mayhem, a lot of polarization, and a lot of division."
Which, he says, "is exactly what ISIS wants to do."
There might be any number of reasons ISIS wants to sow terror in the United States: to provoke a military overreaction, to create a backlash against American Muslims that would fuel its "clash of civilizations" narrative, to demonstrate its reach and power to admirers and thus beat out al-Qaeda for recruits, or even simply to retaliate for defeats in Iraq and Syria at America's hands. It's impossible to know exactly what the group's endgame is with absolute certainty; ISIS doesn't exactly invite journalists and analysts to sit in on its strategy sessions.
But we do know, with some real certainty, that sowing terror is what ISIS wants. This conclusion of Neumann's suggests that one of the best ways to respond to lone wolf attacks — which are both rare and very hard to detect in advance — is to keep them in context. The risk that an American will be killed in a terrorist attack like San Bernardino is extremely low, which means such attacks should not disrupt American daily life or cause us to sacrifice core values like religious tolerance.
There's a simple victory in keeping calm.