Sometime on Wednesday, December 2, a woman named Tashfeen Malik posted a message to Facebook announcing her allegiance to Abu Bakr al-Baghdadi, the leader of ISIS. Shortly after that, she and her husband, Syed Farook, began their attack in the California town of San Bernardino where they lived, ultimately killing 14. Her online pledge is one of several signs that the San Bernardino shooters had been inspired by ISIS's jihadist propaganda. While it is possible that evidence will emerge showing that ISIS had directly ordered or facilitated the attack, so far it has not. It appears that this may have been an attack by so-called "lone wolves" inspired but not directed by ISIS.
The opposite seems to be true in Paris: The mastermind of the attacks, Abdelhamid Abaaoud, apparently had strong ties to the central ISIS leadership and spent time fighting with the group in Syria.
Both attacks were horrific, senseless tragedies that killed innocent people. So why does it matter whether the attacks were directed by ISIS? It's a critically important distinction — and one that almost never gets addressed.
To the victims and their families, of course, it makes little difference whether a terror attack was directed and facilitated by a powerful organization with lots of resources or just committed by a random individual or small group.
But in the bigger picture of US efforts to prevent attacks and counter threats, the distinction between plots that ISIS directs and ones it merely inspires is hugely important. It's a different kind of threat that has different risk factors and requires different solutions.
Any plots directly organized and conducted by ISIS are, by nature, likely to be larger, more sophisticated, and deadlier — but they will also be much easier to disrupt. Lone wolf plots inspired by ISIS or al-Qaeda, on the other hand, are less deadly but also, by their homegrown and often haphazard nature, much harder to spot and disrupt.
Homegrown attacks: often amateurish but harder to catch
In the context of jihadist terrorism, a "homegrown" terrorist attack is one carried out by people who have, on their own, adopted the extremist ideology espoused by al-Qaeda or ISIS and decided to carry out an attack independently, without receiving any direct orders, training, financing, or other support from the central leadership of ISIS or al-Qaeda.
Maybe they read a few issues of ISIS's online propaganda magazine, Dabiq, or watched some YouTube videos of extremist sermons, for example by the now-deceased radical Yemeni American cleric Anwar al-Awlaki, and became convinced that it was their duty to attack America.
They buy a gun or build a bomb using directions they find online, pick a target they think they can attack pretty easily and that maybe is vaguely symbolic, and launch their attack. They might make a "martyr" video, pledge allegiance to al-Qaeda or ISIS, or perhaps just post some sort of manifesto online indicating their intentions. Or they may do none of that and just shout al-Qaeda or ISIS slogans during the attack.
Because the perpetrators of these kinds of attacks have not received any kind of training or direction from al-Qaeda or ISIS, their attacks are often amateurish, target places that are not very secure or well-defended, and are on a much smaller scale.
The 2013 Boston Marathon bombing is a good example of this kind of attack at its worst. The two bombers, Dzhokhar and Tamerlan Tsarnaev, detonated pressure cooker bombs they made themselves using instructions from Inspire magazine, the English-language digital magazine produced by al-Qaeda in the Arabian Peninsula, near the finish line of the Boston Marathon, killing three people and injuring more than 260 others.
Authorities concluded that the Tsarnaev brothers "were 'self-radicalized,' having developed a personal militant ideology that drew from disparate sources without being directly connected to any of them."
Although the Boston Marathon bombing — and the subsequent manhunt for the attackers that shut down the city of Boston — was a dramatic attack that received major media attention, the number of fatalities was thankfully very low (though many more were injured).
If the two attackers had received formal training in bomb-making from a group such as al-Qaeda or had access to more advanced weaponry, the body count could have been much, much higher. But that would have also made the attacks easier for law enforcement to trace and stop, because it would have required the Tsarnaevs to communicate with heavily monitored jihadist groups and perhaps travel abroad for training, all of which might have set off law enforcement red flags. That is the nature of such homegrown attacks — the things that make them less deadly also make them more likely to succeed.
Foreign-directed attacks: more professional and more deadly
A foreign-directed attack is one in which leaders or key members of al-Qaeda or ISIS recruit, train, and deploy an individual or a group of individuals to carry out an attack, usually providing operational guidance (which targets to hit, how to stay under the radar and avoid getting caught before the attack, etc.) as well as resources such as money, fake travel documents, safe houses, and even weapons.
Because of the time, planning, and resources that go into these kinds of attacks, they tend to be much more sophisticated. They usually focus on more secure, well-defended, highly symbolic targets that are harder to attack; may involve near-simultaneous attacks on multiple locations; and tend to kill a high number of people and do a lot of physical damage.
The 9/11 attacks are the ultimate example of this kind of attack. The attacks struck two major symbolic targets — the World Trade Center and the Pentagon (and would have struck a third, the US Capitol, had Flight 93 not crashed in Pennsylvania) — almost simultaneously; killed almost 3,000 people; and caused nearly $2 trillion in damages and other costs. The attacks in Paris, which killed 130, are another example of this, and show just how much deadlier and more destructive such attacks can be.
But these attacks, because they require so much coordination and planning, also give law enforcement and intelligence agencies — which greatly expanded their resources and capabilities after 9/11 — many more opportunities to discover and stop the plots before they're launched. As Paris showed, they do sometimes still succeed, but many such plots are foiled. And foiled plots are costly for the groups behind them, usually sinking lots of time, money, and other valuable resources into them.
What the difference tells us about the terrorism threat
Homegrown attacks are less deadly, which in some ways make them less scary. On the other hand, they can be more frequent because they don't take very long to plan. They are also much harder to prevent, because they usually involve only a small number of people (or even just one person). Since there is often no direct foreign communication, travel, or money transfers, there is not much for intelligence and law enforcement agencies to pick up on. In other words, there are fewer spots along the path from radicalization to execution of an attack for the plot to be disrupted.
Foreign-directed attacks, on the other hand, are much deadlier, as the 9/11 example clearly shows. This makes them much more menacing but also much less frequent, because they take such a long time to plan (the 9/11 attacks were years in the making). They are also easier to prevent, especially with the intelligence and security measures put in place after 9/11. Large, coordinated attacks involve many more people communicating with one another in different countries and traveling across (often tightly controlled) borders. All this means there are a lot more opportunities for intelligence and law enforcement agencies to disrupt the plot before an attack can be carried out.
All of this means that while spectacular and large-scale attacks like 9/11 are becoming less of a threat, we are likely to continue experiencing smaller-scale, yet still deadly, lone wolf–style attacks for the foreseeable future.
In fact, it is in part because post-9/11 security and intelligence measures so succeeded that groups like ISIS and al-Qaeda have begun calling on people in the West to carry out terrorist attacks on their own. Groups like ISIS and al-Qaeda do want homegrown attacks and actively seek to cultivate them — but it's not their first choice. If they could pull off an attack on the scale of 9/11 easily, they would.
So although it seems scary to have more of these smaller-scale attacks, it's important to understand that this is a sign we're doing a good job of preventing 9/11-level attacks. And that's something, at least.