It’s been 16 years since al-Qaeda launched the deadliest terrorist attack in modern history, killing 3,000 people. Almost immediately after the attack, the US government vowed revenge. “When we find out who did this, they're not going to like me as President,” George W. Bush said after the first of the two Twin Towers collapsed, per one aide’s memory. “Somebody's going to pay."
But while the US response inflicted real damage on al-Qaeda, the worrying truth is that in recent years the terrorist group has managed to rebuild itself, taking advantage of the international focus on ISIS to become as strong, if not even stronger, as it was before 9/11.
Before 9/11, the group’s active membership numbered in the thousands worldwide. Today, its quasi-affiliate in Syria alone commands up to 30,000 troops by some estimates. And there are thousands more fighting for al-Qaeda-affiliated groups in places like Somalia, Yemen, Afghanistan, North Africa, and elsewhere. Some of these different branches, most notably the one in Yemen, have skilled international terrorists who have planned sophisticated attacks on the US in the past.
Al-Qaeda has been able to rebuild in large part by capitalizing on the specter of ISIS. As ISIS grabbed headlines by seizing territory in Iraq and Syria and staging terrorist attacks across Europe, al-Qaeda quietly focused on recruiting and building relationships with local militants fighting in chaotic civil wars. The result is that Western counterterrorism efforts focused on ISIS, doing tremendous damage to the group, while al-Qaeda flourished.
Our attention has “basically [been] captured by ISIS as it exists in Iraq and Syria,” says Katherine Zimmerman, a senior analyst on al-Qaeda at the American Enterprise Institute. “And now that it’s finally losing terrain in a rapid fashion, people are looking around the world and saying there’s still a huge threat — and it’s not ISIS.”
This doesn’t mean the threat al-Qaeda poses to Americans is larger than it was before 9/11. Not only have the US and its allies gotten much better at preventing the sorts of large-scale, spectacular attacks al-Qaeda prefers, but it’s also unclear how interested many of these al-Qaeda affiliates are in attacking America at this particular moment. Most of these groups are engaged in protracted, bloody civil wars that demand all of their attention and resources. While they are certainly not fans of the United States, plotting complex, expensive attacks against the US may not be high on their current list of priorities.
Further, much of their phoenix-like success has come from being able to recruit in the shadows of civil wars. A massive attack on the American homeland would disrupt that. “For al-Qaeda, given that they’re on an upward trajectory in many theaters at once and in many cases trying to disguise their presence, carrying out a major attack against the West would be counterproductive,” Daveed Gartenstein-Ross, senior fellow at the Foundation for Defense of Democracies and CEO of the terrorism analysis group Valens Global, says.
But this is al-Qaeda, the group that still claims 9/11 as its greatest success. As long as they remain as strong as they are, a risk of another major attack is still much higher than analysts feel comfortable with. “Ultimately, I do see al-Qaeda’s resurgence as a very clear threat to the West,” says Gartenstein-Ross.
Syria shows how al-Qaeda rose as ISIS fell
Three years ago, ISIS controlled a chunk of Syria and Iraq roughly the size of Great Britain and commanded an army of tens of thousands, a level of strength that made al-Qaeda into an afterthought for most counterterrorism analysts.
But since then, ISIS has lost 78 percent of its territory in Iraq and 58 percent of its territory in Syria. It has lost every major population center save one, its capital of Raqqa, which is currently under attack by the US and its allies. Between 60,000 and 70,000 ISIS fighters have been killed in Iraq and Syria, per a US general’s estimate; a total of between 12,000 and 15,000 remain in the two countries.
Which means that the al-Qaeda-linked group in Syria, called Hayat Tahrir al-Sham (HTS), likely outnumbers ISIS in that country. HTS, which commands somewhere in the neighborhood of 20,000 to 30,000 fighters, is the most powerful fighting force in the rebel-held province of Idlib in northwest Syria and has long been one of the most effective fighting forces in the Syrian civil war.
The story of how al-Qaeda managed to succeed as ISIS collapsed in Syria offers insight into al-Qaeda’s strategy for resurgence more broadly.
The root cause of ISIS’s battlefield defeat in Syria is twofold. First, instead of collaborating, the group alienated other rebel groups fighting against the regime of Syrian President Bashar al-Assad by attacking them repeatedly, rendering it friendless in the region. Second, it antagonized the United States, Europe, and regional powers by annexing territory and conducting international terrorist attacks — both of which made it a pressing threat that needed to be addressed immediately. ISIS was not nearly strong enough to hold off this international coalition, so it started to collapse.
Al-Qaeda did things differently.
Instead of attacking rebel groups, it made common cause with them in their struggle against Assad. By integrating its strategy and even its forces with other rebels, al-Qaeda could spread its ideology and recruit more effectively.
This cooperation also made it harder for the West to target al-Qaeda than ISIS, whose facilities, fighters, and command structure were entirely distinct from the various rebel factions. When the Obama administration bombed an al-Qaeda base in Syria in 2014, anti-Assad rebel groups complained loudly, seeing it (correctly) as a strike on an effective partner.
What’s more, the central leadership of al-Qaeda smartly distanced itself publicly from its Syrian fighters. It allowed HTS, which was then called Jabhat al-Nusra, to publicly announce a “break” from the al-Qaeda organization in 2016. Most (though not all) analysts believe, based in part on intercepted al-Qaeda communications, that this was little more than a branding trick — meant to protect the group from US action by raising doubts as to whether it was really associated with al-Qaeda (and thus a real threat to the US) or not.
“The break is a bit of a wink-wink, nudge-nudge. They’re not genuinely dissociated,” says Mia Bloom, a professor at Georgia State University who studies terrorism. “They’re doing many of the things they did before.”
Finally, al-Qaeda has not launched a big-ticket attack in the West using Syria as a staging ground — unlike ISIS, which has used its territory as a kind of command-and-control center to coordinate shootings, stabbings, and car attacks across Europe.
So while ISIS has used its platform in Syria to go global, al-Qaeda has gone hyper-local. “When you read what al-Qaeda wants to do, it’s not just killing Americans,” Zimmerman explains. “It’s focused on winning the near fights, and it’s actually succeeded in several places — Syria being the exemplar.”
Measured purely by the two groups’ relative strength today, it looks like al-Qaeda’s strategy was (in the long run) the smarter of the two.
The big open question: how much does AQ want to attack the US?
Al-Qaeda has replicated this “localization” strategy — move into a civil war, embed with local forces and harness local grievances, and avoid high-profile attacks on the West — in hot spots around the world.
In Yemen, al-Qaeda has taken advantage of the bloody conflict there to further strengthen its already strong affiliate, al-Qaeda in the Arabian Peninsula (AQAP). According to US State Department figures, AQAP’s strength quadrupled between 2015 and 2016, from 1,000 members to 4,000. This is the al-Qaeda group that analysts believe poses the most direct threat to the West: It planned three attacks on US targets between 2009 and 2012, and is home to master bombmaker Ibrahim Hassan Tali al-Asiri.
In Somalia, the al-Qaeda affiliate al-Shabaab has focused on exploiting clan politics and broader grievances with the corrupt and extremely weak central Somali government. The result, as Harvard fellow Christopher Anzalone explains, is that the group has proven resilient to multiple US and international efforts to crush it.
Even in Afghanistan, where the US still has more than 11,000 troops ostensibly trying to fight al-Qaeda and its Taliban allies, al-Qaeda is regrouping, mostly muscling out a nascent ISIS expansion effort to remain the dominant transnational jihadist group in the country. Al-Qaeda leader Ayman al-Zawahiri, as well as Osama bin Laden’s son Hamza bin Laden, are believed to be located either in that country or in neighboring Pakistan.
All of which raises a question: Would al-Qaeda want to risk all of this success by attacking the United States again?
The experts warning of an al-Qaeda resurgence universally agree that the group owes its rebirth to avoiding the limelight. The US and allied military response to 9/11, as well as beefing-up of homeland security and intelligence capabilities, were devastating for al-Qaeda. Allowing ISIS to distract the world while it quietly rebuilt itself was just about the best thing that could have happened to al-Qaeda.
As a result, it’s genuinely unclear whether al-Qaeda is currently planning another 9/11-style attack in the United States. It’s certainly possible, but it’s by no means certain. On the other hand, ISIS is almost certain to continue to stage smaller-scale attacks despite its military decline. “If we’re talking about what I’d expect in terms of terrorist attacks over the next 12 to 18 months, I definitely would see ISIS as the more dangerous of the two,” Gartenstein-Ross says.
But there are signs this calculus could be changing: that al-Qaeda believes it’s strong enough to once again begin targeting the West.
This May, Hamza bin Laden issued a video with “advice for martyrdom-seekers in the West,” urging al-Qaeda supporters to “follow in the footsteps of martyrdom-seekers before you.” And Monday, on the 16th anniversary of 9/11, al-Qaeda released four statements commemorating the attack, including one showing Hamza’s face on the towers as they burn:
The point, then, is that localization may represent more of a tactic than an overall strategic shift. The group could well shift focus again if it decided that was in its interests, and redeploy its growing strength toward planning more major attacks in the West. This is why it is, in the long run, scarier than ISIS: Its leadership is more deliberate, more strategic, and — at least when it comes to the US — historically far more deadly.
“Al-Qaeda retains the capability to attack the United States, but it decided not to,” Zimmerman says. “I haven’t yet determined what would be the offensive trigger.”