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President Trump’s sudden announcement that the U.S. would withdraw forces from along the Syria-Turkey border has already had dramatic consequences. Turkish armed forces launched an invasion into northern Syria dubbed “Operation Peace Spring,” in response to which the Syrian Democratic Forces (SDF), the predominantly Kurdish military backed by the U.S.-led coalition, has warned that it will be forced to withdraw some of its guards from the Islamic State detention centers and camps to deal with the invasion. Meanwhile, both the Islamic State and Syrian President Bashar al-Assad are taking advantage of the Turkish invasion to launch their own attacks within Syria: On Oct. 9, the Islamic State attacked an SDF position in Raqqa, the former de facto capital of the Islamic State, and Assad’s Russian-backed forces moved further into Manbij and Idlib. The same day, the U.S. reportedly helped move some of the “most dangerous” Islamic State detainees out of SDF custody but subsequently ordered a halt to any further operations against the Islamic State.
As Robert Chesney predicted on Lawfare, Trump’s decision could create the triggering conditions that lead to a collapse of the SDF detention system and a release of thousands of Islamic State fighters. For the same reason, the Turkish invasion of northern Syria underlines the urgency of figuring out how best to detain Islamic State members and hold them accountable for crimes they may have committed while fighting alongside the group.
By some estimates, the SDF is currently holding more than 10,000 Islamic State fighters—including at least 8,000 Iraqis and Syrians and 2,000 foreign fighters—in overflowing temporary detention centers in northeastern Syria. Thousands of family members of detainees are being held in camps for internally displaced persons in the same region. According to Maj. Gen. Alex Grynkewich, the deputy commander of the U.S.-led military coalition to defeat the Islamic State, these camps are potential hotbeds of extremism and the “greatest long-term strategic risk to the overall global campaign against ISIS.” The biggest camp, al-Hol, houses around 70,000 people, including about 10,000 foreigners and 30,000 Islamic State loyalists.
The SDF has consistently asserted that it has limited capabilities to guard these facilities and has continually called for support from the coalition countries. Even before Trump’s announcement on Sunday, the head of the Kurdish forces expressed concern that the camp was at risk of falling under the control of the Islamic State. Despite the general consensus that the status quo was not sustainable, coalition countries have done little to address the problem and there has been no agreement on how to handle these fighters and their families.
Most countries have refused to repatriate their citizens who traveled to join the Islamic State, and some have argued that these foreign fighters should be tried in local courts in Syria or Iraq or stripped of their citizenship. However, even if countries were willing to repatriate their citizens, the majority of detainees who are Syrian or Iraqi would still be left in the hands of the flawed local judiciaries. To simultaneously avoid the problems of repatriation and of leaving the detainees with the local authorities, a small subset of European governments—along with the SDF—have been calling for some sort of tribunal to deal with the detainees.
As Turkey’s offensive continues, it’s useful to review where things stood in relation to the Islamic State detainees before Trump’s announcement and what the future might hold for these prisoners. The situation may depend on who—among the SDF, Turkey, Syria and Russia—gains control of the northeastern territory. But if the security surrounding the detainees deteriorates, the Islamic State will likely exploit the situation and create a further opportunity for its ongoing resurgence.
Local Accountability Proceedings
Although national courts in a conflict region usually provide the most obvious mechanism for criminal proceedings, neither Iraq nor the Kurds controlling territory in Syria have courts that are capable of achieving a just and fair form of accountability. Since 2014, the Iraqi judiciary has been prosecuting thousands of Islamic State suspects, both local and foreign, under broad counterterrorism laws in a way that raises questions about the rigor of process protections. Many defendants in these cases are convicted on charges of membership in a terrorist organization based on confessions obtained in extremely brief trials that run as short as five minutes. These defendants are frequently sentenced to the death penalty or to life in prison. The criminal justice system in the Kurdish Autonomous Administration of North and East Syria faces similar challenges as the Iraqi system and, unlike its Iraqi counterpart, is not internationally recognized. As such, the Kurds are not willing or able to prosecute foreign fighters and have allegedly transferred some of their detainees, including foreigners, to Iraq to stand trial.
This transfer of Islamic State suspects from Syria to Iraq raises additional international legal concerns. Nonetheless, some European countries, including France, may be condoning the practice. Iraq reportedly intends to execute at least seven French nationals who were convicted under charges of being members of the Islamic State. There has been little clarity about exactly how these French citizens who had been fighting in Syria ended up in Iraqi detention centers, but experts suspect that they were transferred to Iraq by the SDF at the request of the French government after the French refused to allow them to return home.
Foreign Fighters: Repatriation and Prosecution
Some see local prosecutions in Syria and Iraq as unrealistic options for foreign fighters, arguing instead for active repatriation followed by possible prosecution in the fighters’ home countries. This is also the option being urged by the U.S. government. Some practitioners even argue that European countries have an obligation to bring foreign fighters to justice under certain international legal instruments (specifically under U.N. Security Council resolutions 2178  and 2396 ).
Countries outside of western Europe, including Kosovo, Kazakhstan, Uzbekistan and Tajikistan have demonstrated the most initiative in repatriating their nationals. Kosovo, the country that had the highest number of its citizens per capita leave to join the caliphate, has made particularly notable repatriation efforts. In April, for example, the Balkan republic brought back 32 women, 74 children, and four men from SDF custody in Syria. The male returnees were immediately placed in detention, pending prosecution, while the women and children were allowed to return home.
Yet, thus far, most western European countries have been reluctant to take back their citizens out of fear that they might not have sufficient evidence to convict the alleged former Islamic State members in domestic court. But, there are still some western European examples of the successful handling of returned foreign fighters:
- In July, a Dutch Islamic State fighter was put on trial in the Netherlands for crimes committed while fighting with the Islamic State in Syria. This was the first trial in the Netherlands dealing with war crimes committed by Islamic State fighters. The defendant had already been arrested and convicted in Turkey, but he was released while waiting on appeal and found his way back to the Netherlands, where he was arrested. He was convicted of violating the personal dignity of a victim (a war crime), participating in a terrorist organization, and preparing terrorist crimes and was sentenced to seven and a half years in prison.
- In June, Italy repatriated one of its citizens who allegedly traveled to Syria in 2014 to fight with the Islamic State. Samir Bougana, also known as Abu Abdullah, was captured in Syria by Kurdish forces in August 2018 as he was planning to enter Turkey. After almost a year in the custody of Kurdish forces, the Italians took him home and plan to put him on trial. The State Department praised the Italian government and urged other western European countries to “follow Italy’s example and take responsibility for their citizens in Syria.”
- In April, a German national, identified as Jennifer W., was put on trial in Munich for enslaving a five-year-old Yazidi girl and letting her die of thirst. Jennifer had traveled to Iraq in 2013 to join the Islamic State and was deported back to Germany in 2016 while trying to renew travel documents in Turkey. She was charged with murder, war crimes, membership in a terrorist organization, and weapons violations; proceedings are ongoing. Jennifer W. is one of a number of female returnees in Germany who are currently on trial or have been convicted for their involvement with the Islamic State in Syria and Iraq. For example, Sabine S., another returnee, was recently sentenced to five years in jail after a German court found her guilty of contributing to the Islamic State’s terror activities in Syria.
- In general, western European countries have also demonstrated a bit more willingness to repatriate children, particularly orphans, who are associated with the Islamic State only through their parents. For example, France brought back 17 children from Syria, Germany brought back four, and Norway repatriated five orphans but chose to leave 35 other Norwegian children behind in Syrian camps. However, these efforts have been ad hoc at best.
The European Union has also recently set up a counterterrorism register meant to facilitate prosecutions of returning foreign fighters from Iraq and Syria. The database is intended to be a repository for information from all EU countries about ongoing investigations and prosecutions of terrorist suspects who fought in Iraq and Syria so that all 28 member states have access to the same data and evidence.
It is also worth noting that there have been ongoing efforts in Europe to investigate and prosecute Syrian citizens who have sought asylum in European countries after allegedly fighting with the Islamic State in Syria or Iraq. Germany, for instance, opened a structural investigation—a broad preliminary investigation without suspects—in 2014 to gather evidence of crimes under international law committed by the Islamic State in Syria and Iraq and recently charged a 33-year-old Syrian citizen with war crimes for acts he committed while fighting with the Islamic State in Syria.
Finally, the U.S. has already brought home a number of American citizens, men and women, who traveled to Syria to fight with the Islamic State. Most have been charged with federal crimes, such as conspiring to provide material support to a designated foreign terrorist organization, and either are awaiting trials or have agreed to plea deals. The children of these U.S. citizens, some of whom traveled with their parents to Iraq or Syria and others of whom were born abroad, have been repatriated without facing charges.
Calls for a Tribunal
There have also been a growing number of calls for the establishment of some sort of ad hoc international criminal tribunal to deal with Islamic State fighters. Leaders from relevant U.N. agencies, Sweden, the Netherlands and the SDF have raised the idea of an international tribunal located in the region to deal with the detainees. While the idea has been gaining traction, supporters of the international tribunal have been vague on the specifics. Academics and practitioners have largely dismissed the idea of an international tribunal.
The most recent iteration of talks about an ad hoc tribunal took place during the U.N. General Assembly when the Netherlands organized a meeting with leaders from Iraq and 20 other countries to discuss accountability mechanisms for the Islamic State fighters. During this meeting, the Netherlands pushed to establish a coalition of countries that can come together to create a tribunal to prosecute high-level Islamic State fighters. This Dutch-proposed international tribunal would run parallel to national prosecutions in Iraq for mid- and low-level perpetrators. Some critics view this as an attempt by the Dutch to avoid having to repatriate their own citizens and deal with them locally.
In light of the Turkish offensive, the future could play out for the Islamic State detainees in a few different ways. It is possible that the SDF will maintain weakened but steady control over the detainees for the foreseeable future and accountability already in place will continue to apply. However, if the SDF’s guards are forced to completely withdraw from their posts at the prisons and camps, the future will become much less clear.
President Trump maintains that Turkey will take control of the Islamic State prisoners, but it is unclear whether any Turkish officials agreed to assume this responsibility and the detainees are located further inside Syria than Turkey is expected to occupy during the current phase of their offensive. Even if the Turkish forces did start to police the camps, there is concern that Turkey’s security would be inadequate given the country’s past failures to crack down on and contain Islamic State cells within its own borders. Alternatively, if not the Turks, then the Russian-backed Syrian forces may end up in control of the detainees since the U.S. withdrawal from Syria has created an opening for Assad to strike a deal with the SDF. Given Assad’s history of putting thousands of Syrians into “filthy dungeons” to be “tortured and killed,” the Islamic State detainees would potentially be subjected to severe conditions with no prospect of a fair trial.
The question of Islamic State fighter detention is particularly urgent given that any deterioration of security at the prisons is likely to lead to greater radicalization and to the escape of hardened fighters. The Islamic State has a history of liberating prisons to boost manpower, and it can be expected to exploit any lapse in detention security to its advantage. Leaving the Islamic State members in detention facilities and displaced persons camps with little oversight has already given the group an opportunity to recruit and indoctrinate new fighters. If security collapses, hardened fighters may escape the prisons and reengage with the 18,000 fighters in Islamic State cells across Iraq and Syria to help fuel an already-burgeoning Islamic State resurgence.