To Whom It May Concern:

We, the undersigned, have devoted decades to the fight against terrorism. We have lost colleagues and friends. We have borne witness to the violent rise of al-Qaeda, the Taliban, and ISIS. We have studied the conditions that brought those groups into being and allowed them to grow in strength. Today, 18 years since 9/11, we see some of the same conditions arising once again in Syria and Iraq, and we will not be silent while history repeats itself.

ISIS may have been defeated on the battlefield; but thousands of Western fighters and their families remain in detention in Syria and Iraq. We do not expect terrorists to attract much sympathy. But the majority of detainees are not terrorists; they are children. At the largest detention camp, al-Hol in northeastern Syria, around two-thirds of the approximately 70,000 detainees areunder the age of twelve. The Red Cross describes conditions there as “apocalyptic.” Childrenroutinely die of malnutrition and hypothermia. Education, medical care, and trauma counseling are practically non-existent. Extremist indoctrination is rife.

Most detainees at al-Hol are from Iraq and Syria, but some are from Western countries. Western governments, for the most part, have refused to take their nationals back. Some have revoked their citizenship. Others have called for an international tribunal based in Iraq, which amounts to another means of avoiding the tough, but necessary, responsibility of dealing with their own citizens. Their trepidation is understandable; by blocking the return of people they regard as dangerous, these states believe that they are protecting their citizens at home.

In reality, however, this “hands off” stance will only create greater danger in the future. Thesqualor of the camps and the lack of just treatment there, especially for children, fuels the Salafi- jihadist narrative of grievance and revenge that has proven so potent in recruiting followers. Many of the women are victims of physical and emotional abuse, but some are also deeply radicalized, preaching toxic ISIS propaganda to the increasingly desperate detainees of al-Hol. Detained children, growing up in brutal conditions and subjected to persistent indoctrination, are at particular risk of becoming radicalized and pursuing the path of terrorism. The denial of citizenship by their home nations will bolster their sense of being, in effect, citizens of the Islamic State, potentially preparing them to form the core of a future resurgence.

Similar conditions brought the modern Salafi-jihadist movement into being in the first place. Thecore membership of the Taliban, a word that literally means “pupils,” were students at extremistSeptember 11, 2019madrassas in Pakistani refugee camps every bit as squalid as al-Hol. Around the same time, a number of Arab countries prevented the return of their citizens who had fought the Soviets in Afghanistan. Some, including Osama bin Laden, eventually had their citizenships revoked. This group of outcasts began coordinating a global network of Salafi-jihadists, whose acts of terrorism—including the 9/11 attacks—changed the world as we knew it.

Later, following the U.S.-led invasion of Iraq in 2003, prolonged detention of Salafi-jihadists and Baathists brought together some of the key elements that would form ISIS. The abuses againstprisoners at Abu Ghraib and elsewhere stoked the group’s calls for revenge against the West.

Today, the danger is even more acute. ISIS has more reserve funding than any Salafi-jihadist group in history, having smuggled an estimated $400 million out of Iraq. It has proven adept at radicalizing young people through social media. And, once radicalized, those young people have myriad opportunities to participate in the global jihad, because affiliates of ISIS and al-Qaeda have embedded themselves in local conflicts from North Africa to the Philippines.

Yet the picture is not all negative. In fact, the present situation represents an opportunity. With most detainees in confined locations and under the control of (more or less) cooperative authorities, it should in many cases be feasible right now to investigate their crimes and, wherever possible, build cases to be pursued in our respective judicial systems. The UN-mandated investigative mechanism UNITAD, which is doing excellent work documenting ISIS crimes in Iraq, should have its mandate extended to Syria. The West should give the Syrian Democratic Forces, which manage al-Hol and other camps, the resources and expertise they need to ensure that extremists cannot use their time in detention as an opportunity to plot more violence. With regard to their own nationals, Western countries should initiate investigations, enact any laws needed to deal with this issue in the future, and follow up by repatriating their nationals—men, women, and children—with a view to prosecution or rehabilitation as they deem appropriate and secure.

By prosecuting militants and their enablers, the West will reveal these people for the violent criminals they are—not the martyrs they claim to be—while at the same time showing that democratic states are capable of delivering justice. By working to deradicalize former supporters, the West will create credible spokespeople, capable of warning would-be recruits about the violence and misery of life in the movement. By reintegrating innocent family members into society, the West will unmask the Salafi-jihadist lie that Western countries have no place for true Muslims. None of this will be easy. But our countries are more than capable of pursuing a limited number of admittedly difficult prosecutions while developing appropriately tailored rehabilitation and reintegration programs.

The choice, then, is clear: pay a relatively small price now, or pay a huge price later. Again and again, we have seen what happens when the West insufficiently reacts to the warning signs ofterrorism: we saw it on September 11, 2001, on the Madrid commuter rail system, at the Bataclan theater in Paris, at the Manchester Arena, at the Brussels Airport, and in other cities across the Western world. Breaking the cycle of violence will not be easy, but it is better than sleepwalking back into the mistakes of the past. The West must act now.

Sincerely,