Henri J. Barkey is Adjunct Senior Fellow for Middle East Studies at the Council on Foreign Relations.
What’s the history of the U.S.-Kurdish alliance in Syria?
The United States began helping the Kurdish militia, known as the People’s Defense Units (YPG), fight against the self-declared Islamic state, known as ISIS, in 2014 when the radical group controlled large swathes of those two countries. The U.S. military and the YPG, which later reconfigured into the Syrian Democratic Forces (SDF), succeeded in beating back ISIS, and their alliance endures to this day. Some two thousand U.S. troops are stationed in northeastern Syria to continue counterterrorism operations against ISIS—still seen as a threat—but the campaign faces considerable new challenges in the aftermath of Syria’s regime collapse in December 2024.
How much of a threat is ISIS today in Syria?
More on:
While the bulk of ISIS has been largely defeated, it continues to recruit and operate in Syria and beyond. The recently deposed regime of Bashar al-Assad, weakened by civil war, had never managed to impose its authority in significant parts of the country and had thus relinquished the fight against the Islamic State to the Americans and the Syrian Kurds.
Assad’s spectacular defeat at the hands of Ha’yat-Tahrir al-Sham (HTS), while welcomed by much of the region and the international community, has raised new concerns for several reasons. First, its roots are in al-Qaeda and al-Nusra, two Islamic fundamentalist movements that also share a great deal of the Islamic State ideology. Second, the new leaders understandably have yet to establish complete control over Syrian territory, and it’s extremely difficult at this point to assess HTS’s cohesion and capabilities. Third, given the gargantuan challenges HTS faces, the likelihood of conflict, instability, and failure is great. This explains, in part, why the United States recently decided to increase its forces from nine hundred to two thousand.
What’s the status of the U.S.-SDF alliance amid the historic upheaval in Syria?
The U.S.-SDF partnership is solid, but it remains challenged by Turkey. From the beginning, then-Turkish prime minister and current President Recep Tayyip Erdoğan have opposed U.S. involvement with the SDF. Turkey feels threatened by the fact that YPG has its roots in the Kurdistan Workers’ Party, the PKK, which has battled the Turks and is listed as a terrorist organization by Turkey and the United States, among others.
For its part, the YPG professes to be a Syrian organization set up to defend Syrian Kurds who have suffered a great deal at the hands of ISIS and successive Syrian governments. The U.S. received commitments from the SDF/YPG that it would not conduct operations across the border into Turkey. Turks, however, are more afraid of the possibility that the Syrian Kurds will negotiate a special status for themselves in post-Assad Syria, just like the Iraqi Kurds carved out a federal region within Iraq at the end of the successive Gulf Wars. Turkey fears that such a development would inspire a similar movement with its own Kurdish minority, which represents some 20 percent of the population.
Turkish leaders have thus far been uncompromising, publicly saying their goal is to eliminate the SDF by force if necessary, and dialing up the intensity and frequency of their rhetoric. Erdoğan recently stated that the SDF has “no choice but to surrender their weapons, abandon terrorism, and disband the organization. The other option is to face [Turkey’s] velvet-gloved iron fist.” His Foreign Minister Hakan Fidan subsequently stated that the YPG’s elimination is only a matter of moments. The government is in effect entrapping itself, perhaps deliberately, by elevating expectations among the Turkish public to pressure Washington and Turkish Kurds, with whom Erdoğan has initiated a new and complicated dialogue intended to convince them to end their support for the armed struggle.
More on:
Turkey has already sent its troops to dislodge the SDF from territories in northwestern Syria on three occasions. In addition, it has created and funded the Syrian National Army (SNA), a militia it uses to attack the Syrian Kurds. The SNA, which is technically part of the umbrella group that fought the Assad regime along with HTS, has been focused on continuing its battle with the SDF with Turkish air support. Washington is caught between the demands of its North Atlantic Treaty Organization (NATO) ally, Turkey, and its continuing need to contain ISIS, a task that is impossible to accomplish without the SDF.
How is the United States navigating this difficult dynamic?
Washington has tried to negotiate cease-fire agreements between the SDF and the Turks. It has got the SDF to make a series of concessions, such as withdrawing its forces to the east of the Euphrates River and abandoning the town of Manbij, demilitarizing Kobane, and promising to eventually get non-Syrian forces that had joined the SDF to leave Syria. Eventually, the SDF is expected to renounce its links to the PKK.
However, the intensification of SNA’s attacks and Turkish anti-SDF rhetoric is another possible reason why the United States increased the number of troops deployed to Syria to two thousand. This is an unmistakable signal to Turkey that while it is willing to accommodate some Turkish demands, Washington will not tolerate a Turkish incursion into the area. The Turkish government could also be rethinking its policy options because the SNA has proven to be quite ineffective of late in fighting the SDF.
HTS, led by Ahmed al-Shaara, has a long-standing relationship with Turkey. Turkey had initially been quite supportive of the creation of al-Nusra by Shaara, and its supply lines ran through Turkey. Ankara also supported them directly, though discretely. Turkey expects that its past ties to HTS will help enlist Damascus in its struggle against the Syrian Kurds. Turkish Foreign Minister Fidan was among the first to visit Damascus along with Ibrahim Kalin, an Erdoğan confidant and head of intelligence. Shaara has publicly stated that all armed groups must be incorporated into a unified Syrian Army, as he expressly referred to the Kurds. This was evidently at the behest of the Turks, who have argued that HTS should take over the battle against ISIS.
HTS, however, does not have the wherewithal to take over the areas controlled by the SDF, much less take the fight to ISIS. Furthermore, such an effort would alienate Washington, whose support HTS desperately needs as it tries to rebuild Syria. Moreover, the U.S. military, which has developed a strong relationship with the SDF over the past ten years, is unlikely to agree to a change of partners. The United States trained and supplied the SDF, which claims to have lost some 12,000 fighters over this period.
Can ISIS be eradicated in Syria?
ISIS has not been subdued despite its loss of territory over the past decade. The Pentagon warned in mid-2024 that its attacks in Iraq and Syria were on track to double from the prior year. The intensification of U.S. air strikes against ISIS in the aftermath of Assad’s overthrow is an indication of Washington’s worries that the group will try to take advantage of the disarray in Damascus. Notwithstanding its assertions that it has broken with its past, HTS’s fundamentalist pedigree is cause for concern because of the lack of information on the organization’s rank and file. Even in Turkey, despite Erdoğan’s claims that ISIS has been defeated, Turkish Interior Ministry figures show that the security services conducted some 1,400 operations against ISIS targets, arresting 1,279 suspects in 2024.
The most significant threat to countries in the region and beyond rests in the prisons in northeast Syria that hold ISIS detainees, where security is provided by SDF forces. Al-Hol is the largest, and as of March 2024, it held more than forty thousand prisoners and their families. The prisoners come not just from Iraq and Syria but also from many other countries, including those in Europe. Conditions at the camp are reported to be difficult at best. There have been numerous escape attempts and one brazen ISIS effort at freeing their comrades in 2022 in Hasaka that ended up with hundreds killed. Were some or all of these detainees to find freedom, there is no telling what they could decide to engage in, given reports of high levels of indoctrination at the detention camps.
The SDF is widely recognized to have done a good job in managing the prisons. The Turkish foreign minister has suggested that the new Syrian transitional government take over the management of the prisons and said Turkey is ready to provide considerable support. But such Turkish requests are unlikely to go far as HTS recognizes it cannot manage the camps. At American urging, Mazloum Abdi, the commander of the SDF, met with Sharaa where they agreed to resolve the crisis in northeast Syria with the goal of “merging” them into the Syria’s armed forces at some point in the future. In a symbolic move, the SDF agreed to hoist the new Syrian flag in areas it controls.
What moves might the Donald Trump administration make in Syria?
The Trump administration is unlikely to undermine the delicate status quo, much to the consternation of Ankara. Trump, during his first term, suddenly announced that having defeated ISIS, the United States would withdraw its 900 soldiers from northern Syria. This led to a crisis within the administration, as U.S. Secretary of Defense John Mattis and many others strenuously objected and eventually convinced Trump to reverse his order. Trump may still believe that U.S. troops should come home, but conditions have changed dramatically in Syria and the region.
Not only is Assad gone, but the transitional HTS regime has much distance to cover before the situation is truly stabilized. Between Assad’s departure and Israel’s determined campaign against Hezbollah and other Iranian assets in Syria, Iran has, for the first time, lost its primary ally along with its supply highway to Lebanon. The balance of power has been completely altered. U.S. troops, while stationed in Syria in pursuit of ISIS, also serve as a significant deterrent to pro-Iran Shi’a militias in Iraq, who may be urged to meddle in Syria or for Iranians to return surreptitiously to Syria. The nine hundred or two thousand U.S. troops is a small price to pay to help sustain the makeover.
The recent tragedy in New Orleans, even if committed by an ISIS adherent without the support of the organization, is a cautionary indicator against Trump acting in haste. It takes every bit of intelligence and effort to prevent massive casualty attacks, which ISIS has excelled in.
Trump will undoubtedly be lobbied to pull the troops out by Erdoğan, with whom he had established a close rapport. However, in the past, this putative “friendship” has not prevented Trump from making decisions that displeased Turkey’s leader.
This work represents the views and opinions solely of the author. The Council on Foreign Relations is an independent, nonpartisan membership organization, think tank, and publisher, and takes no institutional positions on matters of policy.
Will the Shake-up in Syria Undermine the Fight Against ISIS?
The United States appears intent on keeping its counterterrorism alliance with the Kurds in post-Assad Syria despite the strains it is causing with ally Turkey.
January 9, 2025 10:17 am (EST)
- Expert Brief
- CFR scholars provide expert analysis and commentary on international issues.
Henri J. Barkey is Adjunct Senior Fellow for Middle East Studies at the Council on Foreign Relations.
What’s the history of the U.S.-Kurdish alliance in Syria?
The United States began helping the Kurdish militia, known as the People’s Defense Units (YPG), fight against the self-declared Islamic state, known as ISIS, in 2014 when the radical group controlled large swathes of those two countries. The U.S. military and the YPG, which later reconfigured into the Syrian Democratic Forces (SDF), succeeded in beating back ISIS, and their alliance endures to this day. Some two thousand U.S. troops are stationed in northeastern Syria to continue counterterrorism operations against ISIS—still seen as a threat—but the campaign faces considerable new challenges in the aftermath of Syria’s regime collapse in December 2024.
How much of a threat is ISIS today in Syria?
More on:
While the bulk of ISIS has been largely defeated, it continues to recruit and operate in Syria and beyond. The recently deposed regime of Bashar al-Assad, weakened by civil war, had never managed to impose its authority in significant parts of the country and had thus relinquished the fight against the Islamic State to the Americans and the Syrian Kurds.
Assad’s spectacular defeat at the hands of Ha’yat-Tahrir al-Sham (HTS), while welcomed by much of the region and the international community, has raised new concerns for several reasons. First, its roots are in al-Qaeda and al-Nusra, two Islamic fundamentalist movements that also share a great deal of the Islamic State ideology. Second, the new leaders understandably have yet to establish complete control over Syrian territory, and it’s extremely difficult at this point to assess HTS’s cohesion and capabilities. Third, given the gargantuan challenges HTS faces, the likelihood of conflict, instability, and failure is great. This explains, in part, why the United States recently decided to increase its forces from nine hundred to two thousand.
What’s the status of the U.S.-SDF alliance amid the historic upheaval in Syria?
The U.S.-SDF partnership is solid, but it remains challenged by Turkey. From the beginning, then-Turkish prime minister and current President Recep Tayyip Erdoğan have opposed U.S. involvement with the SDF. Turkey feels threatened by the fact that YPG has its roots in the Kurdistan Workers’ Party, the PKK, which has battled the Turks and is listed as a terrorist organization by Turkey and the United States, among others.
For its part, the YPG professes to be a Syrian organization set up to defend Syrian Kurds who have suffered a great deal at the hands of ISIS and successive Syrian governments. The U.S. received commitments from the SDF/YPG that it would not conduct operations across the border into Turkey. Turks, however, are more afraid of the possibility that the Syrian Kurds will negotiate a special status for themselves in post-Assad Syria, just like the Iraqi Kurds carved out a federal region within Iraq at the end of the successive Gulf Wars. Turkey fears that such a development would inspire a similar movement with its own Kurdish minority, which represents some 20 percent of the population.
Turkish leaders have thus far been uncompromising, publicly saying their goal is to eliminate the SDF by force if necessary, and dialing up the intensity and frequency of their rhetoric. Erdoğan recently stated that the SDF has “no choice but to surrender their weapons, abandon terrorism, and disband the organization. The other option is to face [Turkey’s] velvet-gloved iron fist.” His Foreign Minister Hakan Fidan subsequently stated that the YPG’s elimination is only a matter of moments. The government is in effect entrapping itself, perhaps deliberately, by elevating expectations among the Turkish public to pressure Washington and Turkish Kurds, with whom Erdoğan has initiated a new and complicated dialogue intended to convince them to end their support for the armed struggle.
More on:
Turkey has already sent its troops to dislodge the SDF from territories in northwestern Syria on three occasions. In addition, it has created and funded the Syrian National Army (SNA), a militia it uses to attack the Syrian Kurds. The SNA, which is technically part of the umbrella group that fought the Assad regime along with HTS, has been focused on continuing its battle with the SDF with Turkish air support. Washington is caught between the demands of its North Atlantic Treaty Organization (NATO) ally, Turkey, and its continuing need to contain ISIS, a task that is impossible to accomplish without the SDF.
How is the United States navigating this difficult dynamic?
Washington has tried to negotiate cease-fire agreements between the SDF and the Turks. It has got the SDF to make a series of concessions, such as withdrawing its forces to the east of the Euphrates River and abandoning the town of Manbij, demilitarizing Kobane, and promising to eventually get non-Syrian forces that had joined the SDF to leave Syria. Eventually, the SDF is expected to renounce its links to the PKK.
However, the intensification of SNA’s attacks and Turkish anti-SDF rhetoric is another possible reason why the United States increased the number of troops deployed to Syria to two thousand. This is an unmistakable signal to Turkey that while it is willing to accommodate some Turkish demands, Washington will not tolerate a Turkish incursion into the area. The Turkish government could also be rethinking its policy options because the SNA has proven to be quite ineffective of late in fighting the SDF.
HTS, led by Ahmed al-Shaara, has a long-standing relationship with Turkey. Turkey had initially been quite supportive of the creation of al-Nusra by Shaara, and its supply lines ran through Turkey. Ankara also supported them directly, though discretely. Turkey expects that its past ties to HTS will help enlist Damascus in its struggle against the Syrian Kurds. Turkish Foreign Minister Fidan was among the first to visit Damascus along with Ibrahim Kalin, an Erdoğan confidant and head of intelligence. Shaara has publicly stated that all armed groups must be incorporated into a unified Syrian Army, as he expressly referred to the Kurds. This was evidently at the behest of the Turks, who have argued that HTS should take over the battle against ISIS.
HTS, however, does not have the wherewithal to take over the areas controlled by the SDF, much less take the fight to ISIS. Furthermore, such an effort would alienate Washington, whose support HTS desperately needs as it tries to rebuild Syria. Moreover, the U.S. military, which has developed a strong relationship with the SDF over the past ten years, is unlikely to agree to a change of partners. The United States trained and supplied the SDF, which claims to have lost some 12,000 fighters over this period.
Can ISIS be eradicated in Syria?
ISIS has not been subdued despite its loss of territory over the past decade. The Pentagon warned in mid-2024 that its attacks in Iraq and Syria were on track to double from the prior year. The intensification of U.S. air strikes against ISIS in the aftermath of Assad’s overthrow is an indication of Washington’s worries that the group will try to take advantage of the disarray in Damascus. Notwithstanding its assertions that it has broken with its past, HTS’s fundamentalist pedigree is cause for concern because of the lack of information on the organization’s rank and file. Even in Turkey, despite Erdoğan’s claims that ISIS has been defeated, Turkish Interior Ministry figures show that the security services conducted some 1,400 operations against ISIS targets, arresting 1,279 suspects in 2024.
The most significant threat to countries in the region and beyond rests in the prisons in northeast Syria that hold ISIS detainees, where security is provided by SDF forces. Al-Hol is the largest, and as of March 2024, it held more than forty thousand prisoners and their families. The prisoners come not just from Iraq and Syria but also from many other countries, including those in Europe. Conditions at the camp are reported to be difficult at best. There have been numerous escape attempts and one brazen ISIS effort at freeing their comrades in 2022 in Hasaka that ended up with hundreds killed. Were some or all of these detainees to find freedom, there is no telling what they could decide to engage in, given reports of high levels of indoctrination at the detention camps.
The SDF is widely recognized to have done a good job in managing the prisons. The Turkish foreign minister has suggested that the new Syrian transitional government take over the management of the prisons and said Turkey is ready to provide considerable support. But such Turkish requests are unlikely to go far as HTS recognizes it cannot manage the camps. At American urging, Mazloum Abdi, the commander of the SDF, met with Sharaa where they agreed to resolve the crisis in northeast Syria with the goal of “merging” them into the Syria’s armed forces at some point in the future. In a symbolic move, the SDF agreed to hoist the new Syrian flag in areas it controls.
What moves might the Donald Trump administration make in Syria?
The Trump administration is unlikely to undermine the delicate status quo, much to the consternation of Ankara. Trump, during his first term, suddenly announced that having defeated ISIS, the United States would withdraw its 900 soldiers from northern Syria. This led to a crisis within the administration, as U.S. Secretary of Defense John Mattis and many others strenuously objected and eventually convinced Trump to reverse his order. Trump may still believe that U.S. troops should come home, but conditions have changed dramatically in Syria and the region.
Not only is Assad gone, but the transitional HTS regime has much distance to cover before the situation is truly stabilized. Between Assad’s departure and Israel’s determined campaign against Hezbollah and other Iranian assets in Syria, Iran has, for the first time, lost its primary ally along with its supply highway to Lebanon. The balance of power has been completely altered. U.S. troops, while stationed in Syria in pursuit of ISIS, also serve as a significant deterrent to pro-Iran Shi’a militias in Iraq, who may be urged to meddle in Syria or for Iranians to return surreptitiously to Syria. The nine hundred or two thousand U.S. troops is a small price to pay to help sustain the makeover.
The recent tragedy in New Orleans, even if committed by an ISIS adherent without the support of the organization, is a cautionary indicator against Trump acting in haste. It takes every bit of intelligence and effort to prevent massive casualty attacks, which ISIS has excelled in.
Trump will undoubtedly be lobbied to pull the troops out by Erdoğan, with whom he had established a close rapport. However, in the past, this putative “friendship” has not prevented Trump from making decisions that displeased Turkey’s leader.
This work represents the views and opinions solely of the author. The Council on Foreign Relations is an independent, nonpartisan membership organization, think tank, and publisher, and takes no institutional positions on matters of policy.
