A U.S. Army soldier in Iraq holds a captured ISIS flag. ISIS and other groups are prepared to go underground to resume an insurgency. Whether they succeed depends on how well the Syrian and Iraqi governments are able to reestablish security, identify and root out the rebel infrastructures, and manage reconstruction and reconciliation.

While the so-called Islamic State (ISIS) has lost control of its statelet in Iraq and Syria, the war against the remnants of the organization is not over, despite President Trump’s claim to the contrary.[1] Anti-Assad rebels still control various parts of Syria with non-ISIS jihadis controlling Idlib in the northwest and the Kurds commanding the northeast. Fighting over these enclaves will likely occupy the immediate future. In addition, any “deescalation” agreements remain subject to collapse or cancellation at the convenience of Assad and his backers.[2] But the longer-term question is what happens next? Will the wars in Syria and Iraq finally end, or will there be another round of insurgencies? And will ISIS again go underground to rebuild as it has before?[3]

While ISIS and other groups have made preparations for going underground to resume an insurgency,[4] the success of such efforts depends on at least two factors: how well the Syrian and Iraqi governments reestablish effective governance and security and are able to identify and root out the rebel infrastructures;[5] and whether these governments can manage reconstruction and reconciliation, especially reintegration of Sunni Arabs.

Governance and security. Reestablishing effective governance and security requires that national governments enforce and maintain effective control over areas previously held by ISIS or other insurgents. If the governments succeed, it will be much harder for opposition groups to go underground and remain functional.

But restoring security will be extraordinarily difficult. For a start, the anti-ISIS war is not over. Though their command structure has largely been shattered, there are still residual ISIS pockets and cells to dig out.[6] Moreover, the parts of ISIS most likely to have survived—senior commanders and the security apparatus—are the parts most able to regenerate the organization.[7] The war against the terrorists has also been only one aspect of the multi-sided civil war in Syria. There are ample opportunities for further wars there and in Iraq. These may be driven by rival nationalisms: Turkey has demonstrated its readiness to go to war against the Kurds in Syria and has occasionally talked about enlarging its borders,[8] and Iraqi Kurds unsuccessfully tried to do so.[9] Factional rivalries and competing ambitions between regional states[10] as well as Israel’s sustained efforts to prevent Iran’s military entrenchment in Syria could lead to a wider conflagration. Various Sunni states may be prepared to continue support of Sunni factions as a way to distract Iran and other enemies or may look the other way when factions within those states give such support.

It is also possible that the Middle East is in the opening round of multiple civil and proxy wars within Islam: between governments and movements that have weaponized Shiite and Sunni Islam;[11] between Shiite factions allied or opposed to Iran, and among the Sunni jihadists. These wars are likely to be protracted and bloody and will further increase religious polarization and violence within the region and within Islam as a whole, and can potentially destabilize much of the Middle East.

The capabilities of both the Syrian and Iraqi governments are limited; their ability to effectively govern and conduct long-term counterinsurgencies is uncertain. While the collapse of the Iraqi security forces in the face of ISIS has been widely noted, the collapse of the Syrian military was even more comprehensive. The Baghdad government and the Assad regime have only partially recovered, with many of the forces nominally aligned with them in reality being factional militias that serve their own agendas or those of foreign sponsors.[12] This is most prominent in Iraq where the Kurds are effectively an autonomous government and where major parts of the Popular Mobilization Forces militias created in the aftermath of the 2014 Iraqi security collapse are under Iranian control. It is also the case in Syria where its Kurds also desire autonomy and where many militias such as the Lebanese Hezbollah function independently of the Assad regime.[13] Will these forces accept and support government policies with which they (or their patrons) disagree? Or are they more likely to pursue their own agendas, if necessary at the expense of the national governments they nominally support?

Reconstruction and reconciliation. National reconstruction and reconciliation, especially reintegration of the Sunni Arabs, will present uphill struggles. First, there is some question about how much reconstruction the Iraqi and Syrian governments will be able to undertake even with foreign aid. Much of each country has been economically, socially, and physically devastated, both by ISIS rule and by the wars to drive the organization out and their aftermaths.[14]

Ruins in Raqqa, Syria, show extensive damage following repeated battles. There is some question about how much reconstruction the Iraqi and Syrian governments will be able to undertake even with foreign aid. Much of each country has been economically, socially, and physically devastated.

Large parts of Syria have been devastated by the civil war unrelated to ISIS. There are also millions of refugees, mostly Sunnis, which the Assad regime will likely be reluctant to resettle. Meanwhile, both the Iraqi and especially Syrian governments are effectively bankrupt. Assad’s war has been largely bankrolled by Tehran,[15] and his Russian and Iranian patrons are unlikely to be inclined or able to fund the enormous reconstruction costs, estimated to be between $250-300 billion.[16] A preliminary World Bank estimate of Iraqi reconstruction costs from February 2018 was $88 billion.[17] The Trump administration is also unenthusiastic about nation-building, and as of March 2018, had pledged only a $3 billion line of credit.[18] And while the Persian Gulf monarchies have made promises to Iraq,[19] and Riyadh has cautiously opened up to Baghdad to push back against Iranian influence,[20] it remains to be seen whether these governments will actually come up with the money.

Meanwhile, the rest of the international community is likely to experience donor fatigue.[21] Beyond this, is the question of how much of the available money will get to the Sunnis who have been hardest hit: As of early 2019, the Iraqi government had provided virtually no reconstruction money to Ninevah province, which includes Mosul).[22] To whatever degree Syrian and Iraqi Sunni Arabs manage—or are allowed—to recover may be in spite of policies of their governments rather than because of them.

As for national reconciliation, while the Damascus and Baghdad regimes may have made some efforts in that direction in the past, the situations do not look promising. The continuing wars against rebels in Syria will likely be hard and protracted. It is all too likely that ultimately the victors (especially the Assad regime) will pursue a vindictive peace in an atmosphere of religious polarization[23] and widespread individual and group hatred and revenge.[24] Even now, the Assad regime has been confiscating and selling the properties of refugees and those considered rebels.[25]

It is unclear how much the Assad regime will even try to reconcile its Sunni subjects. The Syrian president has made clear his intent to reconquer militarily all of the country, and one must expect the same brutal tactics he has used so far.[26] Assad prefers brutality since his aim is not only to win the war but to intimidate the survivors.[27] The idea that one cannot kill one’s way out of an insurgency is a Western conceit that others, especially the Russians and Middle Easterners, dismiss with contempt—after all, that is precisely what Bashar Assad’s father did to put down a rebellion in the early 1980s.

In Iraq, the previous government of Prime Minister Haidar Abadi made efforts to reconcile the Sunni Arab minority and protect it from blood revenge and collective tribal responsibility for the actions of individual members.[28] Current prime minister Adil Abd al-Mahdi appears to favor a moderate policy, but how much he can actually deliver remains to be seen. He has no independent power base,[29] controls his own government only partially, and has limited or no control over many of the Shiite militias of the Popular Mobilization Forces, who are frequently supported or controlled by Tehran and have driven a sectarian agenda. Meanwhile, it is reasonable to expect that the popular sentiment of much or most of the Shiite and Kurdish populations, not to mention the surviving non-Muslim religious minorities, favor punishing the Iraqi Sunni Arabs for being pro-ISIS or insufficiently anti-ISIS.[30] Villages and tribes often take their own retribution whether it is government policy or not.[31]

Clearly, there are ample grounds for pessimism.

But the situation does not necessarily favor ISIS as the requirements needed to function underground may work against it. While there remains an atmosphere of massive Sunni grievance and a power vacuum that ISIS could theoretically exploit, how well it will be able to do so is still a question.

Australian Abu Khaled is flanked by other ISIS jihadists in an ISIS propaganda video. Foreign fighters provided much of the core strength of ISIS. Most are likely to speak Arabic poorly and to appear non-Arab and will get close attention from the security authorities, hindering them going underground.

For a start, since foreign fighters have been killed, captured, or have fled and not been replaced, ISIS has reverted to being more and more Syrian and (especially) Iraqi. Foreign fighters provided much of the core strength of ISIS and replacing them will be difficult. But even if they stayed, these foreign fighters would be ill-suited for underground resistance in their host countries. Thousands of them came from outside the Arab world, in particular the West, sub-Saharan Africa, Asia, and areas of the former Soviet Union, and are likely to speak Arabic poorly and to appear non-Arab. These foreigners, as well as Arabs with non-Syrian or non-Iraqi Arabic accents, or for that matter anyone non-local, are likely to get close attention from the security authorities, hindering them going underground.

Various world, national, regional, and local security forces will also be trying to identify, locate, and eliminate ISIS holdouts gone underground.[32] In the Mosul campaign alone, the Iraqi authorities had more than 30,000 suspects’ names in December 2016, and by January 2018, had some 6,000 captured ISIS suspects awaiting execution. In addition, some factions may not be waiting on legal niceties. Local and regional services, in particular the Assad regime’s, can be expected to err on the side of excess.[33]

ISIS also made many other enemies who will be out for revenge. Syria’s conflict, in particular, has been a multi-sided civil war with ISIS fighting many other anti-Assad factions, including nationalists and various other jihadists.[34] The situation has also been complex in Iraq. Even if ISIS did have some local support that was not coerced or opportunistic,[35] it ruled as conqueror even at the expense of local allies. Indeed, its first purge after taking over Mosul was of former allies.[36] In particular, ISIS and al-Qaeda factions in Syria have spent extensive time and effort killing each other, and there are irreconcilable major differences between ISIS and al-Qaeda Central, particularly over leadership of the global jihadist movement.[37] These conflicts can be expected to continue underground.

Finally, popular resentment of ISIS’s brutal tactics has produced numerous personal grudges to be settled. An obvious way to settle scores will be to turn in ISIS fighters to the security forces. Financial rewards would be a further incentive. And if government screening seems too lenient, or corrupt, individuals personally may target ISIS members for revenge killings.[38]

ISIS is thus unlikely to have the same favorable atmosphere to maintain or rebuild its underground structure as previously, especially in Mosul, where its predecessor organization, al-Qaeda in Iraq/Islamic State of Iraq, was never really removed even when the U.S. military was present in force,[39] and in Syria, where the Assad regime had tolerated, if not supported, their operations against the coalition in Iraq. ISIS may retain a degree of control in some pockets, but many of its survivors are likely to give priority to their own survival, not continuing the war. They may also turn to crime.[40]

Another complicating factor for ISIS will be losing its claim of the right to rule. Aside from the loss of legitimacy due to losing a war and bringing vast devastation to the people on whose behalf the war was supposedly fought, as ISIS tries to return to the underground its narrative will have been discredited. It will only be able to spin defeat for so long. It is much more difficult to argue from failure than from success, and the physical and psychological attractions of the “caliphate” will no longer exist. ISIS will be unable to offer the thrill of being a warrior for God and a licensed outlaw, or promise the availability of sex slaves for unmarried young men, or the expectation of living in a truly Islamic utopia.

Much of the support ISIS received was due to its claim to be in control of territory. The self-named “caliph” Abu Bakr Baghdadi (above) claimed his position by right of conquest. But without territory, ISIS may find it harder to recruit fighters.

Much of the support ISIS received, especially foreign, was due to its claim to be a genuine state in control of territory and its apparent success in routing its enemies. Previously, ISIS could claim to be living up to its motto of “Remaining and Expanding.”[41] The self-named “caliph” Abu Bakr Baghdadi claimed his exalted position by right of conquest.[42] Since these successes were considered manifestations of God’s favor, what will happen now that those are gone? At what point will it become impossible to ignore that God is no longer intervening on their behalf or that the state Baghdadi claimed to rule is no longer on the map? Assuming Baghdadi has not fled, it will be difficult for him to claim to be ruler of much of anything. He is unlikely to find sanctuary in a neighboring state—such as al-Qaeda Central and the Taliban had in Pakistan and Iran after 9/11 and the previous iteration of the Islamic State had in Syria. However, Turkey remains a remote possibility as the Erdoğan government has been suspiciously lenient toward ISIS and may hope to use ex-ISIS fighters against the Kurds.[43] If Baghdadi is shown to be killed, it will automatically dissolve all oaths of allegiance made to him, which will both dissolve the organization and leave the survivors up for grabs.

While ISIS may find it difficult to recover, these difficulties may not apply to other insurgent groups, in particular Hayat Tahrir ash-Sha’m (HTS) in Syria and whatever Sunni nationalist groups have managed to survive in Iraq.

Hayat Tahrir ash-Sha’m. At one time known as al-Qaeda in Syria,[44] Hayat Tahrir ash-Sha’m split off from ISIS (and also from al-Qaeda) and is, aside from the ambiguous case of the Syrian Kurds, probably the largest of the remaining non-ISIS, anti-Assad factions. Significantly, it appears to have learned from past mistakes and gradually modified its strategy and tactics from those previously standard to al-Qaeda. It may even have made these changes in spite of the policy of al-Qaeda Central, as did other al-Qaeda affiliates and branches, especially in Yemen and Mali.[45] Among its major adaptations,

• It has sought to collaborate and build alliances with existing Islamist (or even non-Islamic) rebel groups and to a degree reflects their concerns.[46] It has thus selectively prioritized local rather than international operations, which means it can potentially tap into significantly larger reservoirs of support than ISIS, such as other jihadists that ISIS has alienated. It can also exploit latent support for jihadism and appeal to the substantial portion of Islamic opinion that is functionally radical by claiming to wage a defensive jihad rather than an offensive one.[47]
• Instead of trying to impose its version of Shari’a immediately, it has sought to do so gradually, pursuing what might be called jihadization from below, intending to cultivate a base of support and ultimately build a mass movement.[48]
• It has been more selective, or at least less indiscriminate, in targeting of terrorist attacks. In 2013, Aymann Zawahiri, leader of al-Qaeda Central, instructed al-Qaeda to avoid mass casualty attacks, especially those that kill Muslim civilians.[49]
• To deal with the collapse of governments, it has tried to set up a governing structure and enforce order. In Syria, it has assumed control of courts and law enforcement, leaving other administration to other groups.[50]

For these reasons, and especially in comparison to ISIS, Hayat Tahrir ash-Sha’m has come to be considered a “moderate” extremist group, the only one that could plausibly provide other factions with protection from ISIS.[51] These changes have the potential to make it appear less foreign, gain some local support, and at least significantly reduce the reasons for al-Qaeda’s past loss of popular support. In particular, a degree of local support may enable Hayat Tahrir ash-Sha’m to maintain an underground organizational structure in Syria even if its current enclave in Idlib is overrun.

Iraq’s Sunni Arab nationalist groups. The situation is different in Iraq. There the al-Qaeda brand has likely been profoundly damaged by ISIS as the direct descendent of al-Qaeda in Iraq/Islamic State in Iraq and the murderously bloodthirsty Abu Musab al-Zarqawi; al-Qaeda cannot claim any separation between itself and ISIS. Further, in Iraq, ISIS has pretty much monopolized the jihadists. However, this handicap does not necessarily apply to other insurgents, especially Sunni Arab nationalist groups. Prior to ISIS, the most significant of these was the Jaysh Rijal at-Tariqa an-Naqshbandia (JRTN, Army of the Men of the Naqshbandi Order /Naqshbandi Army). This is a nominally non-sectarian (though it claims some roots in Sunni-Sufi Islam) and neo-Baathist organization formed by Izzat ad-Duri, one of Saddam Hussein’s top chieftains, after the Iraqi dictator was executed. Largely composed of Saddam-era military officers and officials, it aims to restore the Baathist system.[52] In late 2014, it was considered the second most powerful Sunni insurgent force in Iraq after ISIS, with at least some degree of popular support.[53] In the past JRTN has operated with and hired other groups, using them as a force multiplier.[54] Initially it cooperated with ISIS (which designated a former Baathist general from the JRTN as the first governor of Mosul when it took over), but in 2016, it claimed to be attacking ISIS when coalition forces began the recapture of Mosul.[55] However, at present, no additional information is available on the JRTN, its ties with other groups, with other Sunni nationalist groups, its present situation, or whether the group survived ISIS.

While ISIS may intend to resume its underground existence in Syria and Iraq, this may turn out to be much more difficult than expected. Although at first glance, the postwar environment may appear fertile for the terror group to pursue such a strategy, there are other factors that may make it difficult for ISIS fighters, especially foreigners, to go underground—in particular, widespread factional and popular hostility to ISIS and the loss of theological/ideological and functional legitimacy due to defeat.

But while ISIS may be less of a threat than commonly supposed, this does not mean it will not be a threat at all. ISIS survived and recovered from a previous massive defeat in Iraq because its enemies did not finish the job of eradicating it—a situation with ominous parallels to the present.[56] Even more important, ISIS is not the only force of insurgents in the field, especially in Syria.

Hayat Tahrir ash-Sha’m, ambiguously an al-Qaeda offshoot, has modified its strategy and has pursued a long-game of sinking roots into Syrian society while pursuing jihadization from the ground up. Over time, the group is likely to absorb surviving jihadists from other organizations, possibly including ISIS survivors. Since there is no reason to believe that Assad will modify his murderous method of rule, one should expect at least one or more low-level insurgencies in Syria.

The present situation in Iraq is somewhat less acute, and the country has better prospects for recovery and reconciliation than Syria.[57] But this depends on the Iraqi government effectively carrying out reconstruction and reconciliation policies. If this does not happen, it is reasonable to expect at least a continuing low-level insurgency, either by ISIS remnants or, more likely, by Sunni Arab nationalists.

There is not a great deal Washington can do to influence events in either country. If recent Middle Eastern history teaches anything, it is that one should never underestimate local players’ ability to make bad situations even worse.

[2] Christopher Kozak, “Warning Update: Pro-Assad Coalition Set to Escalate in Southern Syria,” Institute for the Study of War, Washington, D.C., Jan. 31, 2018.

[3] Patrick Cockburn, “Inside Syria: With its enemies diverted or fighting each other, ISIS is making a swift and deadly comeback,” The Independent (London), Mar. 4, 2018.

[4] Patrick Ryan and Patrick Johnston, “After the Battle for Mosul, Get Ready for the Islamic State to Go Underground,” War on the Rocks (Washington, D.C.), Oct. 18, 2016.

[5] John Arterbury, “To destroy the Islamic State, We must follow it into the desert,” The New Statesman (London), Dec. 2, 2016.

[6] NBC News, Jan. 20, 2018.

[7] Asaad Almohammad and Charlie Winter, “From Directorate of Intelligence to Directorate of Everything: The Islamic State’s Emergent Amni-Media Nexus,” Perspectives on Terrorism, Feb. 2019.

[8] Nick Danforth, “Turkey’s New Maps Are Reclaiming the Ottoman Empire,” Foreign Policy, Oct. 23, 2016.

[9] Joost Hiltermann and Maria Fantappie, “Twilight of the Kurds,” Foreign Policy, Jan. 16, 2018.

[10] Liz Sly, “10 new wars that could be unleashed as a result of the one against ISIS,” The Washington Post, Sept. 7, 2016.

[11] Ali Fathollah-Nejad, “The Iranian-Saudi Hegemonic Rivalry,” Belfer Center Special Initiative Iran Matters, Cambridge, Mass., Oct. 25, 2017.

[12] Jack Watling, “After ISIS, Iraq’s Militias Face Another Fight: Legitimacy,” Defense One (Washington, D.C.), Dec. 22, 2016.

[13] Tobias Schneider, “The Decay of the Syrian Regime Is Actually Much Worse Than You Think,” War on the Rocks, Aug. 31, 2016; Roy Gutman, “Assad Used Nerve Gas Because He’s Desperate. Expect Worse to Come,” The Daily Beast (New York), Apr. 12, 2017.

[14] Associated Press, Aug. 13, 2016.

[15] Eli Lake, “Iran Spends Billions to Prop Up Assad,” Bloomberg (New York), June 9, 2015.

[16] Associated Press, Jan. 13, 2019.

[17] Rhys Dubin, “The Post-Islamic State Marshall Plan That Never Was,” Foreign Policy, Feb. 15, 2018.

[18] Newsweek, Feb. 13, 2018.

[19] Dubin, “The Post-Islamic State Marshall Plan That Never Was.”

[20] Fathollah-Nejad, “The Iranian-Saudi Hegemonic Rivalry.”

[21] Carla E. Humud, Christopher M. Blanchard, and Mary Beth D. Nikitin, “Armed Conflict in Syria: Overview and U.S. Response,” Congressional Research Service, Washington, D.C., Apr. 7, 2017, pp. 19-20.

[22] CNN, Mar. 5, 2019.

[23] Brandon Friedman and Uzi Rabi, “Sectarianism and War in Iraq and Syria,” E-Notes, Foreign Policy Research Institute, Phila., Jan. 5, 2017.

[24] Peter Bergen, “Will Iraq survive victory over ISIS in Mosul?” CNN, Mar. 21, 2017.

[25] “Bulldozing Over the Revolution: Syria’s regime is stealing land from its opponents,” The Economist, Nov. 2, 2017.

[26] Ben Taub, “The Assad Files: Capturing the top-secret documents that tie the Syrian regime to mass torture and killings,” The New Yorker, Apr. 18, 2016.

[27] “Report of the Independent International Commission of Inquiry on the Syrian Arab Republic,” United Nations General Assembly, New York, Feb. 2, 2017.

[28] Osama Gharizi and Haidar al-Ibrahimi, “Baghdad Must Seize the Chance to Work with Iraq’s Tribes,” War on the Rocks, Jan. 17, 2018.

[29] Simona Foltyn, “Will Iraq’s Old Divisions Undermine Its New Prime Minister?” Foreign Policy, Feb. 5, 2019.

[30] Emile Hokayem, “The end of the Islamic State will make the Middle East worse,” The Washington Post, Oct. 28, 2016.

[31] VOA News, Jan. 25, 2018.

[32] Noura Hourani and Maria Nelson, “The network: A virtual hunt for Islamic State fighters fleeing Syria,” Syria Direct (Amman), Jan. 26, 2018.

[33] Josie Ensor, “British jihadists fleeing Mosul could face the death sentence in Iraq’s makeshift courts,” The Telegraph (London), Dec. 2, 2016; PBS NewsHour, Jan. 4, 2017; Der Spiegel (Hamburg), May 2, 2017; The Washington Post, Dec. 28, 2017.

[34] Fabrice Balanche, “Status of the Syrian Rebellion: Numbers, Ideologies, and Prospects,” Washington Institute for Near East Policy, Washington, D.C., Nov. 22, 2016.

[35] CNN, Mar. 1, 2019.

[36] Ghaith Abdul-Ahad, “The bureaucracy of evil: how Islamic State ran a city,” The Guardian (London), Jan. 29, 2018.

[37] Brian Fishman , The Master Plan (New Haven: Yale University Press, 2016), pp. 247-59; Daveed Gartenstein-Ross, Jason Fritz, Bridget Moreng, and Nathaniel Barr, “Islamic State vs al- Qaeda,” New America, Washington, D.C., Dec. 2015; Clint Watts, “Deciphering Competition Between al-Qa’ida and the Islamic State,” CTC Sentinel (West Point), July 27, 2016.

[38] Matt Cetti-Roberts, “Mosul’s Avenging Angels; with locals’ help, Iraqi police round up ISIS supporters,” War Is Boring, Mar. 8, 2017; Newsweek, Oct. 2, 2017; ABC News (Australia), Dec. 17, 2017.

[39] Tallha Abdulrazaq and Gareth Stansfield, “The Enemy Within: ISIS and the Conquest of Mosul,” Middle East Journal, Autumn 2016, pp. 525-42.

[40] “Iraq; Military Operation Defeats White Flag,” STRATFOR Snapshots, STRATFOR, Austin, Tex., Feb. 7, 2018.

[41] Dabiq, Al-Hayat Media Center, ISIS, no. 5.

[42] Abu Muhammad al-Adnani, “This Is the Promise of Allah,” Jihadist News, SITE Institute, Bethesda, Md., June 29, 2014.

[43] Meira Svirsky, “Secrets and Lies: Turkey’s Covert Relationship with ISIS,” The Clarion Project, Washington, D.C., Mar. 29, 2016; Uzay Bulut, “Turkey Releases ISIS Suspects,” The Clarion Project, Apr. 3, 2016; Aaron Stein, “The Islamic State in Turkey: A Deep Dive into a Dark Place,” War on the Rocks, Apr. 6, 2016; Patrick Cockburn, “Turkey accused of recruiting ex-Isis fighters in their thousands to attack Kurds in Syria,” The Independent, Feb. 7, 2018.

[44] Colin Clark, “Al-Qaeda in Syria Can Change Its Name, but Not Its Stripes,” Cipher Brief (Washington, D.C.), Mar. 23, 2017.

[45] Charles Lister, “How Al-Qaeda Lost Control of Its Syrian Affiliate: The Inside Story,” CTC Sentinel, Feb. 2018; Thomas R. McCabe, “Has al-Qaeda Learned From Its Mistakes?” Middle East Quarterly, Spring 2018.

[46] Aymenn Al-Tamimi, “The Formation of Hay’at Tahrir al-Sham and Wider Tensions in the Syrian Insurgency,” CTC Sentinel, Feb. 22, 2017.

[47] McCabe, “Has al-Qaeda Learned from Its Mistakes?”

[48] Yasir Abbas, “How al-Qaeda Is Winning in Syria,” War on the Rocks, May 10, 2016; Charles Lister, “The Dawn of Mass Jihad: Success in Syria Fuels al-Qa’ida’s Evolution,” CTC Sentinel, Sept. 7, 2016.

[49] Bruce Hoffman, “Al-Qaeda’s Resurrection,” Council on Foreign Relations Expert Brief, Washington, D.C. and New York, Mar. 6, 2018.

[50] Samuel Heller, “The Governance Strategy of Jabhat al-Nusra and Jabhat Fatah al-Sham,” in Aaron Y. Zelin, ed., How al-Qaeda Survived Drones, Uprisings, and the Islamic State (Washington, D.C.: Washington Institute for Near East Policy, 2017), p. 42.

[51] Colin P. Clarke, “The Moderate Face of al Qaeda,” Foreign Affairs Snapshot, Oct. 24, 2017; Tamimi, “The Formation of Hay’at Tahrir al-Sham.”

[52] Michael Knights, “The JRTN Movement and Iraq’s Next Insurgency,” CTC Sentinel, July 2011; Aymen Jawad Al-Tamimi, “The Naqshbandi Army’s Current Situation in Iraq,” Pundicity blog, Dec. 26, 2014; “Jaysh Rijal al-Tariqa al-Naqshbandia (JRTN),” Mapping Militant Organizations, Stanford University, July 27, 2015.

[53] “Jaysh Rijal al-Tariqa al-Naqshbandia (JRTN).”

[54] Ibid.

[55] Emily Anagnostos, Jessica Lewis McFate, Jennifer Cafarella, and Alexandra Gutowski, “Anticipating Iraq’s Next Sunni Insurgency,” Institute for the Study of War, Washington, D.C., Nov. 30, 2016.

[56] The New York Times, Mar. 7, 2019.

[57] See, for example, Kevin Baron, “The War in Iraq Isn’t Done. Commanders Explain Why and What’s Next,” Defense One, Mar. 22, 2018.