The United States is at risk of another “Mission Accomplished” moment. On Wednesday, President Trump declared by tweet, “We have defeated ISIS in Syria, my only reason for being there during the Trump presidency.” President Trump is right that the United States has made tremendous progress against the Islamic State, and we’ve been honored to support that mission from the White House across two administrations as senior counterterrorism officials. But the Islamic State has not been “defeated” — and our mission in Syria has not been fully accomplished.
The recent Christmas market terrorist attack in Strasbourg that left five dead and at least a dozen injured serves as an all-too-vivid reminder that the threat posed by the Islamic State persists. With the attacker dead, the Islamic State has now claimed the attack as its own. Thankfully, these types of jihadist terrorist attacks in the West have become notably rarer and smaller in scale than they were even just three years ago, when horrific attacks in Paris and San Bernardino, Calif., cast a pall over the 2015 holiday season.
There’s been remarkable progress against the Islamic State in those three years, but perhaps the hardest part is yet to come: addressing the remnants of the group’s core in Iraq and Syria. Indeed, for all of the counterterrorism successes the United States has achieved since Sept. 11 — and there have been many — we’ve yet to figure out fully how to turn the corner from degrading groups like Al Qaeda and the Islamic State to actually defeating them.
Failing to do so can prove deadly: It was, after all, the seemingly dying embers of Al Qaeda in Iraq that rose from the ashes to become the Islamic State and control a territory the size of Britain. Ultimately, it’s vital to remember that groups like the Islamic State and Al Qaeda think of themselves as sublime movements, and thus their ideologues are convinced that they went to war to fulfill divine obligations, making setbacks merely temporary — with remnants sure to carry on the fight.
So, as we look to 2019, it’s important to stay focused on landing a body blow against the Islamic State’s remnants in Iraq and Syria. That includes eradicating the last vestiges of the group’s network of fighters, supporting resurgent governance in the areas the group once held, developing sustainable intelligence sources and law enforcement options for the group’s terrorist network, and increasing the pressure against the group in what remains a virtual safe haven: the internet.
Defeating the Islamic State, at least in Iraq and Syria, begins with eradicating the group’s remaining fighters. (Its fighters elsewhere, such as in Libya and West Africa, will pose a considerable challenge for the foreseeable future, even as important American counterterrorism efforts against them continue.) Finding and targeting the Islamic State’s fighters is a considerable challenge, as they’ve largely been driven into an area of Syria where United States intelligence collection may have fewer inroads, where our main partners on the ground — the Syrian Kurds — have chosen not to follow, and where some local refuge may be available.
The areas successfully cleared of the Islamic State demand continued attention, too. It’s the absence and inadequacies of local governance that often allow terrorists to carve out a foothold in the first place; and the deadly civil war consuming Syria threatens to leave large swaths of the country effectively ungoverned. Working with international partners to provide the resources, training and diplomatic support needed for at least a bare minimum of governance to take root — a Sunni alternative to the horrific brand of governance offered by the Islamic State — is an urgent priority not just for counterterrorism but also for humanitarian reasons. And cutting such resources at this juncture is a dangerous recipe for a resurgent terrorist threat that plays into the Islamic State’s own narratives that only it is capable of governing, as the group indeed tried to do for a time.
The Islamic State has already adapted to its shrinking territorial control by putting in place an underground network that, from the shadows, can inflict destabilizing violence in Syria and Iraq, and potentially throughout the region. This is the same retreat from terrorist insurgency to terrorist network that we saw from Al Qaeda in Iraq; and it demands building U.S., Iraqi, and other partners’ intelligence capabilities to penetrate this network by disrupting its attacks, seizing funds, and detaining those sustaining the network.
Even with diminished territorial holdings, the Islamic State will still be able to radicalize and mobilize followers so long as the group retains a virtual safe haven online. Leading technology companies have stepped up their efforts to contest terrorists’ presence on their platforms, but terrorist groups have adapted, altering their content and regenerating accounts in ways that challenge the companies’ approaches and that connect with would-be followers just long enough to shift those followers into end-to-end encrypted chats to avoid detection. The United States must lead the way by sharing, to the maximum extent classification permits, the latest information on terrorist trends and tactics online with companies so they can use new and emerging tools to contest terrorists’ online foothold.
Stripping the Islamic State of territory and even fighters is not the same as achieving the group’s defeat. Forced from one redoubt, it will reappear in other territories, potentially even in less detectable — but more lethal — forms. It’s not the time to end the mission, lest we soon find ourselves facing a resurgent adversary.
Joshua A. Geltzer is the executive director and visiting professor of law at Georgetown University Law Center’s Institute for Constitutional Advocacy and Protection and a fellow at New America. He served from to 2015 to 2017 as the senior director for counterterrorism at the National Security Council and, before that, as deputy legal adviser to the NSC. Christopher P. Costa is the executive director of the International Spy Museum. From 2017 to 2018, he served as special assistant to the president and senior director for counterterrorism at the National Security Council. He is a former career intelligence officer.