Abstract: The United States works with an array of counterterrorism partners in efforts to fight global jihadi groups such as al-Qa`ida and the Islamic State. Counterterrorism partners give the United States additional reach, reduce the cost of counterterrorism, and often bring strong intelligence and military capabilities to the table. Although many U.S. partners are state governments, some are substate groups, including several that have questionable pasts, troubling associations, poor human rights records, and come with diplomatic complications. These are flawed, but often necessary, counterterrorism partners. In navigating these relationships, the United States must consider the costs and burdens these partners bring and recognize that the United States at times risks undermining U.S. values even as it promotes its interests.
The United States does not fight every battle or bear every burden in its struggle against foreign terrorist organizations. Encompassed in the military doctrine ‘by, with, and through,’ the United States has numerous allies and partners that fight terrorism on their own soil, share intelligence, and at times contribute military force to fight groups such as al-Qa`ida and the Islamic State. In most countries, government security services, police, and military forces are the key partners, but at times non-state actors are the only power on the ground to fight terrorists. In still other cases, such as Afghanistan and Syria today, the government itself may be a current or former terrorist group—but still a potential counterterrorism partner.
Many terrorist groups are active in places where the government is weak or non-existent, making traditional counterterrorism partners more difficult to find. Some groups seek to carve out de facto mini-states in areas where government writ is limited, such as Hezbollah in Lebanon. In recent decades, Sunni jihadi groups in Afghanistan, Iraq, Mali, Nigeria, Somalia, Syria, Yemen, and elsewhere have seized control of local areas and joined civil wars, helping defend Muslims and seeking to transform conflicts to spread their jihadi worldview.1
Non-traditional partners can save U.S. lives and cost little money, especially when compared with deployments of U.S. military forces, which can amount to hundreds of millions or even billions of dollars for small operations. Local forces typically have superior knowledge of their own populations, making them better suited to gather intelligence on terrorist operations or personnel. The United States can minimize a hostile backlash from the local population by relying on forces drawn from local communities and avoiding or minimizing the deployment of its own forces.2
The price of cooperation, however, is high. Many of these forces, while demonstrating a degree of military proficiency, require considerable support and training. These forces also are not guaranteed to be loyal to the United States, and may have political goals, internal or external, that cause diplomatic complications. Another challenge is that some partners or specific units commit human rights violations and maintain ties to various dangerous actors, including terror networks hostile to the United States.
To mitigate these problems, the United States must carefully choose which partners it is comfortable working with, and which can deliver the most advantageous results with limited U.S. resources. The United States should also collect intelligence on its partners, to both ensure the credibility of their intelligence and to monitor for human rights abuses or other nefarious actions of partners. Washington should also not be fully reliant on non-traditional partners. If these actors know that the United States has no other alternatives, the bargaining power of the United States decreases significantly. Where possible, the United States should train alternative forces or increase its unilateral capabilities.
The remainder of this article unfolds in four parts. It first presents three recent instances of counterterrorism cooperation with complicated partners: the Sons of Iraq, Kurdish forces in Syria, and Hay’at Tahrir al-Sham, both before and after it came to lead the government in Syria in 2025. The second section assesses the benefit of such partnerships, while section three outlines their costs as well as their limits. The article concludes by proposing several steps for burden-sharing with troubling partners.
Three Cases Involving Troubled Partners
In the post-9/11 era, the United States regularly worked with a wide range of allies, partners, and non-state proxies. Several of the most effective involved considerable tradeoffs, with many having links to other terrorist groups and poor human rights records. This section looks at three different U.S. relationships: the Sons of Iraq (2006-2009); Kurdish fighters in Syria (2015-present); and Hay’at Tahrir al-Sham, its predecessors, and the new Syrian government (2011-present).
Sons of Iraq
The Sons of Iraq (SoI) emerged in 2006 following the U.S. invasion of Iraq in 2003. After large-scale combat operations concluded in April 2003, the “war after the war” began with insurgent and terrorist activity increasing throughout the country.3 By the start of 2004, insurgent attacks rose to 200 weekly and in April reached 600, largely perpetrated by al-Qa`ida in Iraq (AQI). These trends continued upward throughout 2005, in some cases reaching over 800 incidents a week throughout the country.4
Many Sunni tribes, alienated by the new Shi`a-dominated Iraqi government and bitter toward the United States for its removal of the Sunni-dominated old regime, passively or directly supported the insurgency early on. However, they eventually began to feel alienated by AQI, which not only failed to protect them against Iraqi government attacks, but also used widespread violence against the Iraqi population—conducting attacks against tribal leaders, enacting extreme regulations, and punishing those who did not fully comply.5
In late 2005, many Sunni tribal militias turned away from the insurgents and began attempting to expel them from their territory, a turnaround known as the Anbar Awakening.6 The Sons of Iraq formed from this Awakening as a U.S.-sanctioned counterinsurgency program.7 The United States funded the SoI program, paying fighters $300 a month.8 Perhaps more importantly, the United States provided them with backup and firepower: If AQI or other groups threatened them, the United States would surge forces in the area and provide air support. In addition, the Iraqi government worked with, rather than targeted, SoI leaders. The Iraqi government promised SoI fighters permanent employment after the conflict, with 20 percent of these fighters to be integrated into its security forces and alternative government employment for the remaining 80 percent. In 2007, the surge saw an increase in both U.S. troops in Iraq and the relationship between SoI and coalition forces, and by 2008, SoI had over 100,000 fighters operating in about two-thirds of the country.9
The Sons of Iraq were a critical partner for the United States in decreasing violence from al-Qa`ida in Iraq. While not authorized to engage in offensive operations, SoI fighters operated in their home provinces, acting as local law enforcement, manning checkpoints, and gathering intelligence on the identities of suspected insurgents and locations of weapons caches or IEDs.10 They were particularly important for obtaining local intelligence: They knew their own communities and had legitimacy, making it easy for them to identify foreign fighters and other AQI members who were not from the area. The SoI were not intended as a permanent solution, but a “temporary measure meant to help the Coalition and Iraqi Security Forces move forward in delivering security.”11 By April 2009, coalition forces had transferred all SoI fighters and responsibilities to the Iraqi government.12
The Awakening and subsequent Sons of Iraq program, combined with the U.S. surge, led to several successes against al-Qa`ida in Iraq. Within the first year of the program, U.S. Marines reported that “without the Awakening, the surge would not have stabilized Iraq by the summer of 2008.”13 The SoI “were responsible for finding, collecting, or reporting locations of literally hundreds of munitions caches which CF and ISF were able to recover or reduce.”14 In addition to seizing weapons, they disrupted insurgent propaganda and training information. SoI intelligence led to the capture of five high-value targets and 100 suspected insurgents. There was also a notable decrease in AQI attacks: “attacks against CF, ISF, and local nationals dwindled from nearly 35 in July 2007 to less than 10 in January and March of 2008.”15 An AQI leader from al-Anbar province confirmed that “the turnaround of the Sunnis against us had made us lose a lot and suffer very painfully.”16 There was a reported 70 percent decrease in AQI members within six months, going from an estimated 12,000 to 3,500.17
Although coalition forces praised the short-term successes of the Sons of Iraq, the Iraqi government’s reservations about their integration led to long-term failures of the program. SoI members’ former support of the insurgency, Sunni religion, and ties to the Baath Party in the Saddam era led to mistrust between them and the Shi`a-dominated Iraqi government.18 This, along with bureaucratic and resource constraints, led to a failure from the Iraqi government to provide promised employment to SoI fighters. In July 2010, less than half of the former SoI had been given jobs.19 The Islamic State in Iraq (ISI), which formed in 2006 from AQI, directed recruitment efforts toward former SoI members who had not received permanent employment in the Iraqi government as promised. Security and political officials reported that hundreds of former fighters had either defected to ISI or become double agents.20 Former local Awakening leader Nathum al-Jubouri stated that “members have two options: Stay with the government, which would be a threat to their lives, or help al-Qaeda by being a double agent.”21 The situation further escalated after security forces began arresting former SoI fighters on terrorism charges. In Diyala province, 90 members were arrested between January and October 2010, half of whom were later released for lack of evidence.22
The Sons of Iraq represented a critical component of U.S. counterinsurgency strategy in Iraq, and there are lessons the United States can draw from this partnership. Being able to provide military backup for proxies made them more willing to oppose insurgents. Offering employment and monthly payments were key components to establishing the Sons of Iraq program and were successful in using people who had defected from AQI. Although it was necessary to transfer management of the program to the Iraqi government, failing to establish a mechanism that would guarantee SoI members were properly integrated into the new government allowed the Iraqi state to abandon these promises, causing widespread dissatisfaction among former militia members. ISI was able to exploit these tensions and recruit the very fighters that were essential to the U.S. strategy in Iraq.
The Kurds in Syria
The Kurdish people—through the Syrian Democratic Forces (SDF)—have been critical in U.S. efforts to defeat the Islamic State in Syria. The Kurdish community in Syria is small compared to that of Iran, Iraq, or Turkey: Only around 2.5 million Kurds live in Syria, mostly in the northeast.23 Following the outbreak of the Syrian civil war in 2011 and the rise of the Islamic State in 2014—and the failure of a U.S. program to train Syrian rebels to fight the Islamic State—the United States supported the creation of the SDF in October 2015.24 The SDF is a multi-ethnic military coalition of former U.S.-aligned Kurdish, Arab, Turkmen, Assyrian, and Armenian groups operating in the Democratic Autonomous Administration in North and East Syria (DAANES).25
The Kurdish People’s Protection Unit (YPG) dominates the SDF.26 The YPG is the military wing of the Democratic Union Party, the leading Kurdish political party in northern Syria.27 Kurdish fighters make up approximately 40 percent of the SDF’s estimated 50,000 fighters.28
The SDF established itself as the West’s main—and often only reliable—local partner in its fight against the Islamic State in Syria.29 Its partnership with U.S. Special Operations Joint Task Force – Operation Inherent Resolve (SOJTF-OIR) was instrumental in defeating the Islamic State’s territorial caliphate in March 2019. Since then, Washington has continued supporting—through advise and assist missions, equipment, training, intelligence, and logistics support—SDF counterterrorism operations.30
The overall effectiveness of the U.S.-Kurdish partnership was evident in the operations following the Islamic State’s announcement of its caliphate in 2014 and the official establishment of the SDF. The SDF began clearing villages and towns in northwest Syria with coalition support in 2015.31 The SDF conducted operations in, and successfully liberated, key sites, including the Tishrin Dam in 2015, Raqqa in 2017, and Deir ez-Zor in 2019.32 In most of these operations, the United States provided intelligence, standoff strikes via air and other platforms, and other critical support, while the SDF did much of the heavy fighting on the ground, with losses estimated at 11,000 SDF soldiers during this time.33
The SDF role continued following the defeat of the physical Islamic State caliphate in 2019. Washington continued to focus on advising the SDF on “partnered patrols” and “combined exercises.”34 Advisors conducted training on counter-IED tactics and “noted improved capability in that area.”35 As one example of operations, in a June 2020 mission, the SDF detained 69 Islamic State members and seized multiple weapons and ammunition caches.36 From December 2024 to February 2025, the SDF reported that it had carried out 75 operations against the Islamic State.37
During operations against the Islamic State from 2014 to 2019, the SDF established prisons and detention camps to hold Islamic State fighters and their affiliates. The SDF maintains control of these prisons today, with an estimated 50,000 Islamic State-affiliated individuals detained, including women and children linked to fighters.38
The prisons and camps were a short-term solution that has become a difficult longer-term issue. These prisons and camps have caused numerous concerns regarding the effectiveness of such camps, human rights abuses by SDF forces, and the radicalization risk it carries for those imprisoned.39 The United States will likely continue to support these prisons, even indirectly, due to a lack of realistic alternatives for what to do with the Islamic State-affiliated individuals. Several E.U. countries do not wish to repatriate their citizens who traveled to Syria to fight alongside the Islamic State.40
While the Islamic State’s physical caliphate fell in 2019, there are still an estimated 2,500 Islamic State fighters operating in Syria and Iraq today.41 In addition to the continuation of Islamic State attacks, there are key complications and policy failures that have hindered the U.S.-SDF partnership. The SDF’s affiliation with the Kurdistan Workers’ Party (PKK) complicates the U.S.-Turkey relationship. The PKK is a Kurdish separatist group originally formed to create an independent Kurdish state in Turkey, and the United States has designated it as a foreign terrorist organization (FTO) since 1997.42 The YPG was formed by former PKK members and maintains links to the PKK.43 Turkey views the two groups as directly linked, making the SDF complicit in all PKK activity. Following a pause in fighting, violence between the PKK and Ankara resumed in 2015, subsequently increasing Turkish attacks against Kurdish-controlled territory. Turkey, along with its Syrian allies, seized territory in northeast Syria in 2018 and 2019, forcing the SDF to shift troops and resources away from their counterterrorism goals and putting two important U.S. allies in conflict.44
Further, when SDF troops redeployed to respond to Turkish-backed forces, as was done in October 2019, it decreased the number of troops guarding detention camps.45 The Ain Issa camp went from 700 guards to 60 or 70. After Turkish bombs struck near the camp, an estimated 850 detainees escaped, 100 of whom were reportedly not recaptured.46
The United States has established a counterterrorism partnership with the SDF that avoids other regional dynamics, including ethnic tensions, governance, or security concerns from other states. The limited nature of the partnership has both benefits and consequences, however. Ankara’s continued attacks against the SDF will hinder its ability to protect the territory it controls, guard Islamic State prisons, and conduct counterterrorism operations.
Hay’at Tahrir al-Sham, the New Syrian Government, and Counterterrorism in Syria
Hay’at Tahrir al-Sham (HTS, or the Organization for the Liberation of the Levant) emerged from the Syrian civil war that began in 2011. After over a decade of hard fighting, in December 2024 HTS led the overthrow of the regime of Bashar al-Assad and assumed power in Syria, officially establishing a new government in March 2025.
After the civil war began, a host of jihadis, both local and foreign, joined the fray.47 HTS grew out of the jihadi civil war that began in Syria in 2013 between the Islamic State in Iraq and Syria, which later became the Islamic State, and various other jihadis, including those linked to al-Qa`ida, particularly Jabhat al-Nusra. During this time period, the United States regularly bombed al-Nusra and tried to kill its leaders. U.S. officials believed that al-Nusra members planned external operations that would target the United States and its allies and that al-Nusra’s growth in Syria would enable a long-term al-Qa`ida presence there that would increase the risk of international terrorism.48
After having fallen out with the Islamic State, Jabhat al-Nusra then publicly split from al-Qa`ida in 2016 and formed a new organization that, over time, became HTS, with over 10,000 fighters under arms.49 Since 2017, HTS has controlled parts of Idlib Province. The leader of Jabhat al-Nusra, Abu Mohammad al-Julani, retained control of HTS and is now the leader of Syria, going by the name of Ahmed al-Sharaa. In 2018, the U.S. Department of State designated HTS as a terrorist organization because of its Jabhat al-Nusra legacy, and this lasted until July 2025. The United Nations continues to designate HTS.50
Despite these ties, HTS and after December 2024 the new Syrian government, has repeatedly attacked and suppressed al-Qa`ida-linked individuals, Islamic State forces, and the Lebanese Hezbollah in areas under its control. The enmity between HTS and Hezbollah runs deep. The Lebanese Hezbollah closely backed the former Syrian government of Bashar al-Assad, and when it controlled the Idlib area, HTS cracked down on Hezbollah and Iran. Even before that, in the days when it was Jabhat al-Nusra, the group conducted cross-border attacks and suicide bombings against Hezbollah targets in Lebanon and arrested Hezbollah fighters in Syria.51
Bad blood between HTS and the Islamic State has persisted for over a decade. During its time in control of Idlib, Islamic State fighters refused to recognize HTS’ authority, and the Islamic State kidnapped, assassinated, beheaded, and otherwise attacked HTS officials and fighters and tried to coerce the population under HTS’ control. In response, HTS security services arrested (and at times killed) Islamic State fighters—over 62 operations in total.52 By 2018, HTS had successfully suppressed Islamic State attacks in areas it controlled.53
The United States, however, was slow to recognize the genuine break between HTS and other jihadi groups, in part because of continuing contact, rhetoric support, and other linkages and uncertainties.54 In 2013, as the break between Jabhat al-Nusra and the Islamic State was beginning, the two groups continued to conduct joint operations, and al-Julani even praised the head of the Islamic State.55 Islamic State leaders, including two of its self-proclaimed caliphs, also tried to hide out in HTS territory. Leading HTS scholar Aaron Zelin assesses that HTS probably was not aware of their presence there and that the leaders were simply taking advantage of the relative anonymity they enjoyed in this area, but even the possibility of cooperation was troubling.56 Even as these possible ties continued, HTS may have also been a U.S. counterterrorism partner: Syria expert Wassim Nasr contends it is possible that by 2017, HTS was providing information on al-Qa`ida and other groups to enable U.S. targeting.57
Since taking power in Syria, the government (led by former HTS members) has continued to act against the Islamic State and Hezbollah, and it is not known to have provided support to any externally oriented terrorist groups. Before taking power, HTS tried to disrupt the flow of arms to Hezbollah in Lebanon from Iran, which for years has used Syria as a transit route. HTS has also disrupted Hezbollah cells in parts of Syria. With the Syrian government’s tacit support, the United States had continued airstrikes against the Islamic State in Syria, working with the Syrian Democratic Forces, which operate uneasily under the new government and control several governorates in Syria where the Islamic State remains active. The Syrian government, acting on information provided by U.S. intelligence, has also stopped an Islamic State bombing attempt in Damascus. The new government also shared information it gleaned from arrests to help target Islamic State operatives in Iraq.58
HTS was valuable as a counterterrorism partner before it led the overthrow of the Assad government, and the regime it leads today remains valuable as a counterterrorism partner for several reasons. The Syrian regime exercises control of much of Syria and, as such, controls the legal system; commands a large number of police, intelligence, military, and paramilitary figures; and otherwise is able to monitor and disrupt Islamic State and Hezbollah cells and operations. Sharing information from arrests and raids also allows Iraq and other countries to disrupt terrorist cells on their soil. In addition, HTS leaders’ jihadi background gives it familiarity with jihadi networks, key individuals, and other vital components of groups such as al-Qa`ida. The Syrian regime’s disruption of Hezbollah’s presence in Syria removes a longstanding pillar the Lebanese group relied on and also makes it harder for Iran to support Hezbollah. According to Sebastian Gorka, the president’s senior counterterrorism advisor, “We are working to try and make Damascus better at doing counterterrorism.”59
Despite these advantages, the new Syrian government poses several difficulties, some severe, as a counterterrorism partner. Although the group is not known to have active ties to al-Qa`ida, individuals in what was HTS maintain ties to terrorists of various stripes from their days as Jabhat al-Nusra.60 It is difficult to separate out how much contact, if any, is operational, especially with regard to external operations. HTS also had ties to Central Asian groups that have their own links to al-Qa`ida and the Islamic State.61 Making this unclear picture even murkier, it is difficult to know HTS-linked individuals’ genuine beliefs and true intentions. HTS in 2021 praised Hamas operations against Israel, and its ideologues in the past praised attacks in the West, including a beheading in France in 2020.62 These associations and possible sympathies raise the risk of being wrong about whether HTS has truly changed and, in so doing, the United States would be providing assistance to a regime led by secret terrorists sympathizers and supporters.
In addition to these troubling associations, the Syrian government, run by al-Sharaa and other members of what was HTS, as a whole is weak: It does not control all of Syrian territory, and Syria’s economy suffers from many problems as a result of over a decade of civil war and decades more of economic mismanagement. As a result, the government’s resources are stretched thin and groups such as the Islamic State remain active in parts of Syria. This will limit the value of the Syrian regime as a counterterrorism partner, even though it still offers many benefits. Beyond its counterterrorism performance, al-Sharaa appears to have authoritarian leanings, reflected both in HTS’ policies when, as a rebel group, it governed the Idlib area and when government-linked Bedouins and others have attacked groups such as the Druze and other perceived opponents they often paint as apostates.63 To be clear, the regime so far is less brutal than the Assad regime and makes gestures to include various Syrian communities, but its commitment to an open system remains unclear, and the apparent toleration of violence against the Druze raises troubling questions.64 Bolstering the Syrian regime in the name of counterterrorism thus may strengthen an authoritarian government.
A Necessary Evil?
As with other counterterrorism partners, working with groups like the Sons of Iraq, SDF, and (indirectly) HTS both as a rebel group and as the government of Syria reduces the burden on the United States. These groups have provided, or provide, much of the fighting power against key terrorist groups active in the Levant, which has reduced the cost to the United States and the risk to U.S. personnel. By providing training, intelligence, resources, and military support to these three entities, U.S. counterterrorism efforts have been more effective and far cheaper than they would have been with a more unilateral approach.
In all three instances examined above, the United States had few alternatives to the partners in question. Because terrorist groups are likely to operate in areas where the government is weak, the United States will often have to work with substate groups or other non-traditional partners, some of whom will have troubling histories or unsavory ties, as part of its CT efforts. In Syria, for example, the Obama administration saw the Assad regime as an enemy and repeatedly tried to work with various Syrian factions, spending hundreds of millions of dollars to little avail—only the SDF proved a competent and politically acceptable partner for the United States. The new Syrian government led by former HTS members is now the most powerful force in the country, and its cooperation is vital when seeking to suppress Islamic State remnants there. Similarly, support for the Sons of Iraq became necessary because existing Kurdish and government allies in Iraq had little support in Sunni areas where AQI was strong—indeed, they were often seen as an enemy force. The need for effective counterterrorism cooperation has often trumped concerns over the histories, associations, or other actions of these partners. Common counterterrorism goals between the United States and the three partners described has guided such cooperation and allowed each party to overcome concerns.
In addition to fighting power, partners on the ground offer intelligence and legitimacy. By working with fighting forces drawn from local communities as with the SoI and SDF, the United States was able to develop a granular intelligence picture. This helped identify al-Qa`ida and Islamic State fighters and their supporters and, just as importantly, reduce the likelihood of arresting or killing individuals not affiliated with the group and thus reducing the risk of blowback from the local community.
The Costs and Risks of Troubling Partners
Non-traditional partners come with their own problems and risks. Although all of these partners demonstrated a degree of military proficiency, they have many limits. Both the SoI and the SDF required considerable U.S. airpower and other military support to conduct effective operations. There was also a noticeable shift in the SDF’s capabilities—both in military strength and local intelligence capability—once operations began moving south to the Deir ez-Zor governorate, where there were no Kurdish communities. The battle in Deir ez-Zor lasted twice as long as Mosul, for example.65 Further, forces that Assad supported were able to lift the siege in the town of Deir ez-Zor in two months, while the SDF’s military campaign to the east lasted over a year.66
Many partners are involved in human rights abuses. HTS, for example, governed territory it controlled in an authoritarian manner, subordinating minority groups, and that record today, as it has pivoted to leading Syria, raises many questions.67 SDF forces have been accused of forcefully entering into cities the Assad regime pulled out of, detaining or killing civilians, torturing prisoners in its detention camps, and recruiting child soldiers.68 One observer described some SoI forces as “hunt[ing] al-Qaeda down with vengeance. They dragged al-Qaeda guys through streets behind cars… It was pretty much just a ruthless slaughter.”69 Such partners are also not confined to U.S. rules of engagement and can operate without accountability to the international community. This risks U.S. resources or weapons being used in unintended ways, with the United States potentially being implicated for its assistance. Nor are these partners necessarily aligned with the United States, especially after the immediate shared enemy is defeated. They have come together due to shared interests, but they seek to maximize the power of their community or faction, even if it conflicts with broader U.S. goals.
These partners often have troubling associations. The SoI grew out of AQI, and HTS grew out of the jihadi movement in Syria. In both cases, this background gave them superior knowledge of their eventual terrorist enemies, but it also risks lingering ideological sympathy and, as happened with the SoI, some members could later join a terrorist group if conditions change.70 It also increases the risk that weapons, intelligence, and funding might be diverted to terrorist groups.
These partners also cause diplomatic complications, including with host or neighboring governments. Turkey, an important NATO ally, saw the Kurdish-dominated SDF as a potential threat to its own stability and firmly opposed U.S. support for the group. The SoI’s independence angered the government of Iraq, which saw it as a rival as well as a counterterrorism partner. The new Syrian government, which is led by many former HTS members, will be important for containing the Islamic State and Hezbollah, but Israel sees the government as a potential threat and has launched military strikes on its forces, putting the United States at odds with an important ally.
Future Considerations on Burden-Sharing
Because the United States is reluctant to deploy large numbers of its own forces to fight terrorists everywhere around the globe, it will continue to rely on local actors, and this will often lead to strange bedfellows. Gorka, the president’s senior counterterrorism advisor, noted that he considers the Taliban a cooperative counterterrorism power.71 In addition to Afghanistan, the United States is expanding ties to the new Syrian government, and, in the future, Washington might consider increasing efforts to combat jihadi groups in Africa, which could involve an array of unsavory partners. In such cases, the partners’ poor human rights records, ties to terrorists, and diplomatic complications will make them troubling counterterrorism allies.
The United States will need to approach burden-sharing with a clearer understanding that such cooperation is inherently transactional, fragile, and shaped by shifting local power balances. Taliban cooperation with the United States against the Islamic State Khorasan (ISK) branch is based on the threat ISK poses to the Taliban’s rule and is further complicated by the Taliban’s relationships with different power brokers within Afghanistan itself. Providing the Taliban with intelligence on ISK is sensible, but the long-term U.S.-Taliban relationship is likely to remain fraught.72
Furthermore, reliance on these partners complicates long-term strategy and demands sustained U.S. engagement beyond immediate battlefield objectives—for which the United States must prepare. Partners such as the Sons of Iraq show that tactical gains can collapse if the United States fails to support governance, economic inclusion, and political reintegration after fighting ends. When U.S. commitment is uncertain or when host governments later sideline or punish these partners, groups may splinter, re-arm, or even defect to terrorist organizations—as occurred when many former Sons of Iraq members were recruited by the Islamic State. Therefore, burden-sharing must be paired with long-term political planning and monitoring to avoid undermining initial security gains.
Future burden-sharing will require the United States to accept a persistent tension between effectiveness and values. Working with actors tied to prior insurgencies or human rights abuses risks moral compromise, diplomatic friction with allies, and reputational damage. The Taliban, for example, have a poor human rights record, and Israel is hostile to the new Syrian government.73 Yet, refusing cooperation because of these or similar concerns may leave the United States without partners in key theaters. The implication is that burden-sharing going forward will not simply involve distributing military responsibilities. It will require continuous risk management: vetting partners, collecting intelligence on their behavior, maintaining fallback options, and being prepared to withdraw or shift support when partners diverge from U.S. interests. Burden-sharing will remain essential, but it will continue to be a strategic balancing act rather than a stable or low-cost solution. CTC
Iselin Brady is a student in the Security Studies Program at Georgetown University.
Daniel Byman is a professor in the School of Foreign Service at Georgetown University and the Director of the Warfare, Irregular Threats, and Terrorism Program at the Center for Strategic and International Studies.
© 2025 Iselin Brady, Daniel Byman
Citations
[1] Thomas Hegghammer, “The Rise of Muslim Foreign Fighters: Islam and the Globalization of Jihad,” International Security 35:3 (2010): pp. 53-94; Daniel Byman, Road Warriors: Foreign Fighters in the Armies of Jihad (Oxford: Oxford University Press, 2019).
[2] Many of these points are developed in the literature on proxy wars. See, inter alia, Andrew Mumford, Proxy Warfare: War and Conflict in the Modern World (Cambridge: Polity Press, 2013); Tyrone L. Groh, Proxy War: The Least Bad Option (Stanford: Stanford University Press, 2019); Vladimir Rauta, “Proxy Warfare and the Future of Conflict: Take Two,” RUSI Journal 165:2 (2020): pp. 1-10; and Daniel Byman, “Outside Support for Insurgent Movements,” Studies in Conflict & Terrorism 36:12 (2013): pp. 981-1004.
[3] Richard Shultz, “‘The Irreducible Minimum’: An Evaluation of Counterterrorism Operations in Iraq,” PRISM 7:3 (2018): pp. 102-117.
[4] Ibid.
[5] Najim Abed al-Jabouri and Sterling Jensen, “The Iraqi and AQI Roles in the Sunni Awakening,” PRISM 2:1 (2010): pp. 3-18.
[6] “Iraqi Government Assumes Responsibility for All ‘Sons of Iraq,’” DVIDS, April 1, 2009.
[7] Nizar Mohamad, “A Coalition of Negatives: The Case of the Sons of Iraq and the US in their Counterinsurgency Alliance,” Journal of Military Strategic Studies 18:4 (2018): pp. 149-176.
[8] Farook Ahmed, “Backgrounder #23: Sons of Iraq and Awakening Forces,” Institute for the Study of War, February 21, 2008.
[9] Govinda Clayton and Andrew Thomson, “The Enemy of My Enemy is My Friend … The Dynamics of Self-Defense Forces in Irregular War: The Case of the Sons of Iraq,” Studies in Conflict & Terrorism 37:11 (2014): pp. 920-935.
[10] Ahmed.
[11] Ibid.
[12] “Iraqi Government Assumes Responsibility for All ‘Sons of Iraq.’”
[13] Shultz.
[14] Andrew W. Koloski, “Thickening the Lines: Sons of Iraq, A Combat Multiplier,” Military Review (January-February 2009): pp. 41-53.
[15] Ibid.
[16] Ahmed.
[17] Ibid.
[18] Ibid.
[19] Adam Weinstein, “U.S. troops transitioning ‘Sons of Iraq’ to local control,” U.S. Army, December 9, 2008.
[20] Timothy Williams and Duraid Adnan, “Sunnis in Iraq Allied With U.S. Rejoin Rebels,” New York Times, October 16, 2010.
[21] Shultz.
[22] Williams and Adnan.
[23] “Kurds in Syria,” Minority Rights Group, March 2018.
[24] Hassan Hassan, “The Battle for Raqqa and the Challenges after Liberation,” CTC Sentinel 10:6 (2017).
[25] Eric C. Bullard, “Syrian Democratic Forces,” EBSCO, 2025.
[26] Hassan, “The Battle for Raqqa and the Challenges after Liberation.”
[27] Genevieve Casagrande, “The Road to Ar-Raqqah: Background on the Syrian Democratic Forces,” Institute for the Study of War, November 22, 2016.
[28] Mohammed Hassan, “Building Syria’s new army: Future plans and the challenges ahead,” Middle East Institute, June 12, 2025.
[29] Wladimir van Wilgenburg, “Syrian Democratic Forces (Syria),” European Council on Foreign Relations, n.d.
[30] Ibid.; “SDF Begins Raqqa Offensive, Progress Continues in Mosul,” U.S. Department of War, June 6, 2017.
[31] Terri Moon Cronk, “US-led coalition’s support to continue after Raqqa’s liberation, Army major general says,” U.S. Army, November 2, 2017.
[32] Ibid.; Seth Frantzman, “The strategic Tishrin Dam has become a flashpoint in post-Assad Syria,” FDD’s Long War Journal, January 26, 2025.
[33] “Squaring the Circles in Syria’s North East,” Middle East Report N°204, International Crisis Group, July 31, 2019.
[34] “Home: Who We Are,” Operation Inherent Resolve, n.d.
[35] Ibid.
[36] Brandon Ames, “Syrian Democratic Forces Display Strength, Capabilities through Successful Operations,” U.S. Army Central, July 20, 2020.
[37] Samer Yassin, “SDF carries out 75 anti-ISIS operations since December – Spokesman,” North Press Agency, February 17, 2025.
[38] Ido Levy, “Supporting the SDF in Post-Assad Syria,” Washington Institute for Near East Policy, December 13, 2024.
[39] “Report to Congress on An Interagency Strategy with Respect to ISIS-affiliated Individuals and ISIS-related Detainee and Other Displaced Persons Camps in Syria,” U.S. Department of State, 2025.
[40] Van Wilgenburg. For further research on how to deal with foreign fighters detained by the SDF, see Brian Michael Jenkins, “Options for Dealing with Islamic State Foreign Fighters Currently Detained in Syria,” CTC Sentinel 12:5 (2019).
[41] Caroline Rose and Colin P. Clarke, “The Return of ISIS,” Foreign Affairs, September 18, 2025.
[42] “Kurdistan Worker’s Party (PKK),” National Counterterrorism Center, April 2025.
[43] Van Wilgenburg; “Counter-terrorism Pitfalls: What the U.S. Fight against ISIS and al-Qaeda Should Avoid,” Special Report N°3, International Crisis Group, March 22, 2017.
[44] Mohammed A. Salih, “US Policy in Northeast Syria: Toward a Strategic Reconfiguration,” Foreign Policy Research Institute, May 6, 2024.
[45] Martijn Vugteveen and Joshua Farrell-Molloy, “Turkish Military Offensive in Syria: Consequences for Counter-Terrorism Operations,” International Centre for Counter-Terrorism, June 28, 2022.
[46] Ibid.; Aron Lund, “What is the ‘Khorasan Group’ and Why Is the United States Bombing It in Syria,” Carnegie Endowment, September 13, 2014.
[47] Byman, Road Warriors, pp. 164-203.
[48] Martin Chulov, “Al-Nusra Front cuts ties with al-Qaida and renames itself,” Guardian, July 28, 2016.
[49] “Hay’at Tahrir al-Sham (HTS): TNT Terrorism Backgrounder,” Center for Strategic and International Studies, October 4, 2018; Daniel L. Byman and Jennifer R. Williams, “ISIS vs. Al Qaeda: Jihadism’s global civil war,” Brookings Institute, February 24, 2015.
[50] Marco Rubio, “Revoking the Foreign Terrorist Organization Designation of Hay’at Tahrir al-Sham,” U.S. Department of State, July 7, 2025; Jason M. Blazakis, “Understanding the Trump Administration’s Delisting of Hay’at Tahrir al-Sham,” Just Security, July 18, 2025.
[51] “HTS Condemns U.S. Terror Designation, Demands Evidence of AQ Link,” SITE Intelligence Group, June 1, 2018; Aaron Y. Zelin, “Jihadi ‘Counterterrorism:’ Hayat Tahrir al-Sham Versus the Islamic State,” CTC Sentinel 16:2 (2023); Aaron Y. Zelin, “The New Syrian Government’s Fight Against the Islamic State, Hezbollah, and Captagon,” CTC Sentinel 18:3 (2025).
[52] Zelin, “The New Syrian Government’s Fight Against the Islamic State, Hezbollah, and Captagon.”
[53] Zelin, “Jihadi ‘Counterterrorism.’”
[54] “Amendments to the Terrorist Designations of al-Nusrah Front,” U.S. Department of State, May 31, 2018.
[55] Zelin, “Jihadi ‘Counterterrorism.’”
[56] Ibid.
[57] Wassim Nasr, “The Syrian Civil War Part 1,” “Conflicted” podcast, February 12, 2025, see minutes 27 and 31.
[58] Zelin, “The New Syrian Government’s Fight Against the Islamic State, Hezbollah, and Captagon;” Warren P. Strobel, Ellen Nakashima, and Missy Ryan, “U.S. shared secret intelligence with Syria’s new leaders,” Washington Post, January 24, 2025.
[59] “Sebastian Gorka on the Trump Administration’s Approach to Counterterrorism,” C-Span, August 21, 2025.
[60] Michelle Nichols, “Exclusive: UN report sees no active Syrian state links to Al Qaeda,” Reuters, July 11, 2025; “Twenty-second report of the Analytical Support and Sanctions Monitoring Team submitted pursuant to resolution 2368 (2017) concerning ISIL (Da’esh), Al-Qaida and associated individuals and entities,” United Nations Security Council, July 27, 2018.
[61] Kathleen Collins, “Uzbek Foreign Fighter Groups in the Syrian Jihad: The Evolution of KIB and KTJ from 2011 through 2025,” CTC Sentinel 18:9 (2025).
[62] Zelin, “Jihadi ‘Counterterrorism.’”
[63] Ibid.; Beatrice Farhat, “Syria: Nearly 100 killed in fighting between Druze, Sunni tribes,” Al-Monitor, July 14, 2025.
[64] Christopher Blanchard, “Syria: Transition and U.S. Policy,” Congressional Research Service, September 5, 2025.
[65] Hassan Hassan, “A Hollow Victory over the Islamic State in Syria? The High Risk of Jihadi Revival in Deir ez-Zor’s Euphrates River Valley,” CTC Sentinel 12:2 (2019).
[66] Ibid.
[67] Nury Turkel et al., “Factsheet: Religious Freedom in Syria,” United States Commission on International Religious Freedom, November 2022.
[68] “2023 Country Reports on Human Rights Practices: Syria,” Bureau of Democracy, Human Rights, and Labor, U.S. Department of State, 2023; “Syria 2024,” Amnesty International, n.d.
[69] Jon Moran, “State Crime, Irregulars and Counter-Insurgency,” State Crime Journal 4:2 (2015): pp. 154-174.
[70] Williams and Adnan.
[71] “Sebastian Gorka on the Trump Administration’s Approach to Counterterrorism.”
[72] “Senior Study Group on Counterterrorism in Afghanistan and Pakistan: Final Report,” United States Institute of Peace, May 14, 2024; Dan De Luce, Mushtaq Yusufzai, and Tom Winter, “The Enemy of my Enemy: Biden Admin Weighs Working with the Taliban to Combat ISIS-K,” NBC News, July 3, 2024.
[73] “Afghanistan: Events of 2024,” Human Rights Watch, n.d.
