Early on January 3, U.S. airstrikes near Baghdad International Airport killed Iranian Islamic Revolutionary Guard Corps’ Quds Force (IRGC-QF)b Major General Qassem Soleimani and Iraqi politician and militia leader Abu Mahdi al-Muhandis, who was deputy chief of the Popular Mobilization Commission and the founder of the Kata’ib Hezbollah militia. These strikes occurred against a background of rising escalation between the United States and Iran in Iraq, particularly after December 27 when Kata’ib Hezbollah, a prominent Iranian proxy, killed a U.S. citizen and pro-Iranian militia members attacked the U.S. embassy in Baghdad just four days later.1
Considered by many to be one of the principal architects of Iran’s extensive regional reach, Soleimani cultivated relationships with dozens of proxies throughout the Middle East and beyond.2 But while the international focus on Soleimani’s death is warranted, the death of al-Muhandis is significant in its own right, both due to his role in Iraq, but also in what it signals about what Soleimani’s, and by extension Iran’s, priorities in Iraq were. In one strike, the United States removed two of the most critical actors in Iranian regional strategy, and the global audience was left wondering: what is next for IRGC-QF’s role in the region, particularly its relationships with its partner militias in Iraq and Syria?c
The Iranian Response
The fallout from the strike is already reverberating throughout the region, as Iranian Supreme Leader Ayatollah Ali Khamenei has vowed retaliation for Soleimani’s death.3 The IRGC-QF commander was a favorite son of Iran, and, in Iran and other areas, the physical and virtual outcry over his death has been guttural. Thousands of Iranian citizens took to the streets to protest his assassination,4 in part due to the Islamic Republic’s coordination of a show of support.5 Online, sympathizers posted on Twitter, echoing a call for a “severe revenge” against the United States.d Khamenei reportedly had a soft spot for Soleimani, favoring him for meetings with foreign dignitaries and giving him considerable autonomy in constructing Iranian regional strategy,6 particularly with regard to proxy relationships.7 Given Soleimani’s popularity among the Iranian people and the Supreme Leader, Tehran—already plagued by internal political and societal fissures—will likely seek a strong counter to demonstrate a resolute, unified response.8
The initial response occurred on January 7 when Iranian forces launched a salvo of ballistic missiles on two Iraqi military bases: Ain al-Assad airbase in Anbar Province in western Iraq and another in the northern Kurdish capital of Erbil, both of which housed U.S., Iraqi, and international troops.9 As of the writing of this article, no casualties were reported, lending credence to those who have called the retaliation “carefully calibrated,”10 notably as a way for Tehran to save face domestically and follow through on its threats internationally.e There is additional evidence to suggest that Iran’s retaliation is not yet complete, though this may be posturing: a senior Iranian military commander on January 9 stated a “harsher revenge” is yet to come.11
In the immediate aftermath of the strike on Soleimani and al-Muhandis, Khamenei appointed Soleimani’s replacement: IRGC-QF Deputy Commander Brigadier General Esmail Qaani.f Qaani was Soleimani’s right hand for the last two decades: he was appointed deputy commander at or around the same time Soleimani was made commander.12 He seemingly has considerable operational background in Africa and Central Asia, specifically in Afghanistan and Pakistan, and he managed IRGC-QF’s financial disbursements to various partners.13 Some consider Qaani to lack the refinement and gravitas that Soleimani possessed,14 but his experience and capability within the IRGC is undeniable. Additionally, while it is true that a great deal of Iran’s proxy network in Iraq, Syria, Lebanon, and Yemen was tied to Soleimani’s personal nurturing,15 the IRGC-QF has directorates in countries in Asia, the Levant, Europe, Africa, and the Americas.16 In other words, the overall efficacy of the IRGC-QF over time has never been entirely contingent on one individual, and Qaani’s experience in other theaters has undoubtedly prepared him to take control of the organization. Additionally, although Soleimani’s influence was likely felt throughout the organization, it is an institution that will continue to operate regardless of who is in command.17 These factors, coupled with Qaani’s close relationship with and ideological proximity to Soleimani, indicate the potential for IRGC-QF activities to pick up more or less where they left off.18
While one should not, therefore, overstate the impact of Soleimani’s death, it would also be a mistake to suggest this is not a significant loss of capability and experience for the IRGC-QF. Qaani’s preparation and the institutional nature of the IRGC-QF aside, Soleimani was the architect of Iran’s regional strategy.19 The Supreme Leader and Soleimani had congruent aspirations for the Islamic Republic’s expanding influence in the region, and much of the present proxy network design is a result of Soleimani’s vision.20 Additionally, Soleimani was central to the network’s success: he was a charismatic partner to Iranian-sponsored militias in the region, traveling extensively to meet with their leaders and key stakeholders.21 As such, he became an international symbol of the IRGC’s effectiveness and power.22 g
Iranian regional influence peaked in 2018, when Hezbollah solidified control of the Lebanese parliament, Iranian-backed militias supported Assad’s government in the aftermath of the Islamic State’s territorial loss, and the Iranian-sponsored militias were integrated into the Iraqi political and security systems.23 Over the course of the last few months, a series of protests in these areas chipped away at Iran’s influence throughout the region. In Lebanon, weeks of protests contested Hezbollah’s influence.24 The dwindling of the Syrian civil war and restructuring of the conflict landscape also adjusted Iran’s influence in Damascus, forcing Tehran to reinforce its soft-power approach in Syria.25 In Iraq, protests since October have called for the removal of not just Tehran’s influence, but that of all external actors. Iran and its proxies were initially able to violently counter the demonstrations,26 but that ability diminished quickly as the protests persisted.
Regional Implications: Iraq
In many ways, Iraq is critical for Iran’s strategy in the region, serving as a gateway into Syria and a physical buffer against Saudi Arabia. Iran has long-backed proxies in Iraq, including the Badr Corps and the Supreme Council for Islamic Revolution in Iraq (SCIRI),27 whose progeny continue to collaborate with Iran to this day. Since the U.S. invasion in 2003, Iran has strategically backed Iraqi politicians and proxies to protect itself against a hostile Iraqi government and put pressure on U.S. troops in the country.28 Presently, Iran directly backs a contingent of the most prolific militias in the Hashd al-Shaabi, or Popular Mobilization Forces, including Kata’ib Hezbollah, Asa’ib Ahl al-Haq, and Badr Organization, among others.29 For example, the IRGC-QF provided a broad portfolio of support to Harakat al-Nujaba from 2013-2019, including training, weapons, and funding.30 During this time frame, Iranian officials (overwhelmingly IRGC personnel) met with Harakat al-Nujaba roughly 30 times. Soleimani attended about five of these meetings, highlighting the earlier point about his close relationships with Iranian proxies.h
From Iran’s perspective, its reach in Iraq has suffered a setback as a result of Soleimani airstrike, at least temporarily. This is possibly just as much a result of the death of al-Muhandis as it is due to the death of Soleimani. Largely regarded as “Tehran’s man in Baghdad,”31 al-Muhandis was crucial in implementing much of Iran’s directives with respect to the Hashd.32
Al-Muhandis’ death “highlights Iran’s influence in Iraqi armed groups.”33 An Iraqi national, he fled to Iran after Saddam Hussein came to power and fought on the Iranian side during the Iran-Iraq War.34 i Al-Muhandis has been involved in two of the most prominent Iranian-backed militias in Iraq: he led the Islamic Supreme Council of Iraq’s Badr Brigades in the 1990s, and in the power vacuum after Hussein’s death, al-Muhandis founded Kata’ib Hezbollah.35 Notably, he was integral to the founding and success of the Hashd al-Shaabi.36 As Michael Knights wrote, “the central nervous system of IRGC-QF influence in Iraq is Abu Mahdi al-Muhandis and Kata’ib Hezbollah, which maintains a stranglehold over most of the key relationships and posts in the PMF structure.”37 Toward this, he was also central to the Iranian-led suppression of Iraqi demonstrations in October 2019.38
Despite this blow to Iranian influence in Iraq, there are other Iranian partners in the Hashd al-Shaabi, including Qais al-Khazali, the leader of Asa’ib ahl al-Haq; Akram al-Kaabi, commander of Harakat al-Nujaba; and Iran’s long-time fair-weather friend, Muqtada al-Sadr.39 Most notably, in the aftermath of the strike, al-Sadr reactivated the long-retired Mahdi Army, a group responsible for stoking sectarian conflict in Iraq from 2004-2008.40 j Not all are absolutely firm in their partnerships with Iran, however. For example, al-Khazali has wavered in his support for Tehran on multiple occasions.41 That said, these connections should mean that Iran still has a direct line to various proxies in Iraq, many of which control swaths of territory.42
Much of Tehran’s reach in Iraq—and the rest of the region—will be determined by how Iran reacts to the strikes and evolves in its strategy in Baghdad.k In addition to the strikes, the United States designated Asa’ib Ahl al-Haq (AAH) as a foreign terrorist organization and sanctioned two of its leaders,43 l demonstrating a multi-pronged approach to diminish Iranian influence in Iraq, where and how it can.m The increased attention from the United States and pressure from the Iraqi public to remove Iranian influence could have implications on how effectively Iran can operate in Iraq through its proxies. Collectively, these two factors indicate a less permissive environment for Iranian influence and Tehran will likely need to make adjustments towards its proxy network in Iraq, a challenging feat given the present policy was decades in the making. For instance, it may be that IRGC-QF officials may meet with Iraqi partners at secondary locations outside Iraq, making meeting more cumbersome and difficult to coordinate and more susceptible to operational security failures. Alternatively, it may be that Iran opts for Hezbollah to act as intermediary between it and its Iraqi proxies, which is more common in its Syrian strategy, as discussed later in this article. It could also have implications for the amount of tactical support Iran may provide proxies: training militants and shipping weapons, among other forms of materials, may be more challenging for the IRGC-QF under more scrutiny from the United States.
Iran’s continued entrenchment in Iraq has considerable implications for U.S. forces, as the U.S. military’s presence in Iraq has become more contested since the summer, after a series of U.S. and Israeli airstrikes on Iranian-supported militias within the Hashd al-Shaabi.44 With the killing of al-Muhandis (an Iraqi official), Washington may have further stoked tensions for the 5,000 and counting U.S. troops in Iraq, as evidenced by the most recent parliament vote for the expulsion of U.S. troops.45 Even so, the United States has a number of allies in the Iraqi parliament and may be able to work with them to remedy tensions.46 Separately, the U.S. military’s focus on Iranian escalations could detract from the fight against the Islamic State. A potential removal of troops from Iraq may create a vacuum in certain parts of Iraq and Syria for the Islamic State to regenerate.47 n Already, there is evidence that the pause in U.S. military support during the past month, as tensions with Iran escalated, has directly impacted Iraqi armed forces’ ability to conduct trainings and operations against the Islamic State.48 Additionally, the contingent of about 1,000 U.S. troops still deployed in Syria depends on the Americans in Iraq for support.49
Regional Implications: Syria
A similar line of thought can be extended to Iraq’s neighbor to the west, where Iranian influence was probably impacted but not crippled as a result of Friday’s airstrike. Because of its relatively stronger position in Syria, Iran has more options in the long-term to retaliate against the United States in this theater.
Iran and Syria have a long-standing relationship, dating back to the Iran-Iraq War.50 At the onset of the Syrian civil war, Iranian support of Shiite actors in Syria was an ideological and geostrategic endeavor to protect the Assad regime and project power in the Middle East and to counter Saudi Arabian, U.S., and Israeli influences in the region.51 Iran approached this strategy by partnering with the Assad regime and Russia, while sending in proxies from Iraq and elsewhere.52 o Iran established several militias in Syria, such as the Liwa Abu Fadl al-Abbas network, to complement Syrian and Iranian armed forces, including the IRGC.53 Even as recently as March 2019, there were reports of Tehran and Damascus cooperating to form a Syrian militia that would implement Iran’s directives in the country.54 Iran’s activity in Syria provides an avenue for the potential solidification of Iran’s long-term goal of connecting an air and land bridge from Tehran to the Mediterranean, thereby having a route to exert influence and equip its proxies.55 At the height of Iran’s influence, it was not uncommon for it to provide multiple forms of support to Syrian groups. For example, in the case of Jaysh al-Shabi, the IRGC-QF provided various forms of tactical and operational support, including training, weapons, and funding, from 2012-2015.56 In this theater, Iran heavily leveraged Lebanese Hezbollah as an intermediary. On more than one occasion, Hezbollah established, trained, and maintained Iranian proxies in Syria.p Lebanese Hezbollah founded two Iranian proxies in the country, Harakat al-Imam Zain al-Abedin and Quwat al-Ridha.57 In the case of the former militia, Hezbollah also recruited for the group, primarily from the Deir ez-Zor province where the bulk of Iran’s influence and activity seems to be centered.58
Iran’s influence in Syria was solidified in late 2019 after U.S. forces withdrew.59 Notably, this led to an expansion of Iranian entrenchment in northeastern Syria,60 q both directly and through its proxies.61 Many of the Iranian proxies in Iraq operate and wield influence in Syria,62 including facilitating financial support from the IRGC to Syrian militants and providing educational and religious social services to local populations, notably in Deir ez-Zor.63
Iranian-backed militias in Syria (to include both Syrian groups and Syrian branches of Iraqi groups) will likely be better able to weather the fallout from the Soleimani airstrike than their counterparts in Iraq. They may serve as an avenue for Iran to regroup its Middle East strategy. The relative weakness of the Assad regime and Syria’s geographic proximity to Iran’s regional adversaries—Saudi Arabia and Israel—could be one way for Iran to project its influence. That said, if Iran must focus on consolidating power in Iraq (or on conflict with the United States), it may distract from its goals in Syria. If escalation with U.S. forces continues elsewhere, Iran may struggle to maintain its hold on Damascus, providing an avenue for additional Russian influence over the country and Assad. It is possible that instead of direct involvement, Hezbollah may act in Tehran’s stead to maintain the Iranian-backed proxy network in Syria. As previously discussed, the Lebanese group already has a great deal of clout in the country and is a formidable partner.64
In sum, it is difficult to know how the Iranian government will evolve its policy to maintain influence and relevance in Iraq and Syria after Soleimani’s death. In Iraq, Tehran will seek to maintain a buffer against Saudi Arabia, a pathway into Syria, and a friendly government in Baghdad, which may be challenging given additional scrutiny by the United States and the Iraqi public. Similarly, in Syria, Iran will want to keep supporting Assad and actualize the land and air bridge from Tehran to the Mediterranean to maintain a pathway to Lebanese Hezbollah. With a fractured domestic public and government in Tehran, it seems unlikely that Iran will do anything to jeopardize its precarious position in the region. Much will depend on Qaani’s ability to fill Soleimani’s shoes in terms of maintaining relationships with the proxies.
There are some signs that Iran’s regional proxy network may not slow in terms of its operations. First, al-Muhandis’ replacement has a long-standing relationship with Tehran: Hadi al-Ameri, presently an Iraqi parliamentary official and commander of the Badr Organization, has been tapped as al-Muhandis’ successor.65 Second, the Islamic State may have an opportunity to regenerate if the United States has to refocus on escalations, however limited, with Iran. Additionally, with the Iraqi people and government’s growing dissatisfaction with U.S. forces, a potential withdrawal could mean the United States is no longer able to use or leverage Iraqi military facilities and/or station its forces and assets there.r This could negatively affect its priorities in the Middle East, notably in countering Iran. Should the Islamic State continue to be a threat, the Iranian-backed contingent in the Hashd will continue to be needed in Iraq to secure contested areas and fight the group.s In Syria, where Iran’s influence has not changed as considerably as it has in Iraq, Tehran may elect to continue its existing policy and leverage Hezbollah as an intermediary. Additionally, while it is true that a great deal of the proxy network in Iraq and Syria was shaped by Soleimani’s personal touch,66 the IRGC-QF is an institution and Soleimani has been replaced by an experienced leader.67 In short, the proxy war that Iran has fought in earnest in the region since the inception of the Islamic Republic is far from over, and is likely just entering a new phase of evolution.
[a] The author would like to thank CTC Director Brian Dodwell and CTC Director of Research Daniel Milton for their invaluable feedback on previous drafts of this article.
[b] IRGC-QF is also referred to as Nirooy-e Sepah-e Qods-e (QF) Sepah-e Pasdaran-e Enghelab-e Eslami (IRGC). This body is primarily responsible for extraterritorial missions for the Iranian government but has some internal reach. For more information, see “The IRGC Quds Force,” IranWire, April 9, 2019.
[c] Some of the content of this article is drawn from an ongoing CTC study by the author. The focus of this project is Iranian-sponsored militias in Iraq and Syria, the countries on which this article focuses. This is not to dismiss the importance of Iran’s regional policy in Yemen and Lebanon.
[d] Sympathizers used the hashtag, “انتقام_سخت” (a severe, or harsh, revenge) threatening U.S. forces and citizens, using images of rows of caskets draped with American flags, and other related imagery.
[e] This is partially evidenced from reports about the strike in Iranian state media. The semi-official, IRGC-linked Tasnim News Agency stated that, “at least 80 Americans were killed” during the attack, which was completed by missiles with “such a high velocity that American defense systems” were unable to intercept. For specifics, see “Exclusive: US Base in Iraq Hit by Iranian Fragmentation Missiles,” Tasnim News Agency, January 8, 2020; “Source: At Least 80 Americans Killed in IRGC Attack on US Base in Iraq,” Tasnim News Agency, January 8, 2020.
[f] Alternatively spelled in English as: Ismail Ghani.
[g] Despite his effectiveness, Soleimani suffered from some mistakes in recent years, such as botched operations and backing failed political candidates. For more information, see Michael Knights “Does Soleimani’s Death Matter? Findings from a 2019 Workshop,” Washington Institute, January 3, 2020.
[h] These observations are based on preliminary results of a CTC study by the author examining Iranian-sponsored militias in Iraq and Syria.
[i] When al-Muhandis moved to Iran, he changed his name to Jamal al-Ibrahimi, which he kept upon returning to Iraq in 2003. After his involvement in the 1983 bombings against the US and French embassies in Kuwait was found out, he fled to Iran once again, only to return after the withdrawal of U.S. troops in 2011. See “Who was Abu Mahdi al-Muhandis?” Middle East Eye, January 3, 2020, for more information.
[j] The Mahdi Army was formally disbanded in 2008.
[k] The author would like to thank CTC Research Associate Muhammad al-`Ubaydi for his insight here.
[l] The author would like to thank Cynthia Loertscher for her insight here.
[m] The author would like to thank CTC Associate Seth Loertscher for his insight here.
[n] A recent issue of Al Naba, the Islamic State’s weekly online newsletter, discussed the Soleimani strike and its consequences for its opponents (seemingly Iran, Iraq, and the United States). For more information, see Al Naba, Issue 216, January 9, 2020. The author would like to thank CTC Research Associate Muhammad al-`Ubaydi for his insight here and translation of the newsletter.
[o] According to Knights, Soleimani suggested the alliance with Russian forces. For more information, see Knights, “Does Soleimani’s Death Matter?”
[p] These observations are based on preliminary results of a CTC study by the author examining Iranian-sponsored militias in Iraq and Syria.
[q] The author would like to thank CTC Associate Seth Loertscher for his insight here.
[r] The author would like to thank CTC Director of Strategic Initiatives Don Rassler for his insight here.
[s] Various Iranian-supported Hashd militias effectively control parts of Iraqi territory. For instance, within Baghdad, several militias, including Kata’ib Hezbollah, Saraya Salam, and AAH, Badr Organization, and Kata’ib al-Imam Ali, share dominance of different neighborhoods and parts of Diyala province in Iraq where the Iraqi army is stretched thin.
 Jason M. Blazakis, “The US Recently Made a Smart Move Toward Iran. Killing Soleimani Wasn’t It,” Defense One, January 3, 2020.
 Claire Parker and Rick Noack, “Iran has invested in allies and proxies across the Middle East. Here’s where they stand after Soleimani’s death,” Washington Post, January 3, 2020.
 Alexander Smith, “Iran vows revenge and ‘harsh retaliation’ after U.S. kills its top general,” NBC News, January 3, 2020.
 “Protests sweep Iran after US assassination of top general Qassem Suleimani,” Guardian News, January 3, 2020; “The Killing of Gen. Qassim Suleimani: What We Know Since the US Airstrike,” New York Times, January 3, 2020.
 Masih Alinejad, “Don’t believe Iranian propaganda about the mourning for Soleimani,” Washington Post, January 6, 2020; Kasra Naji, “Soleimani: Why huge crowds turned out for Iran commander’s funeral,” BBC, January 7, 2020.
 “Soleimani Receives Iran’s Highest Military Medal From Khamenei,” MENAFN, March 11, 2019; Mehrzad Boroujerdi, “Javad Zarif Returns—to a Foreign Ministry Still Out in the Cold,” Foreign Affairs, March 6, 2019.
 Michael Knights “Does Soleimani’s Death Matter? Findings from a 2019 Workshop,” Washington Institute, January 3, 2020; Parker and Noack; Ali Soufan, “Qassem Soleimani and Iran’s Unique Regional Strategy,” CTC Sentinel 11:10 (2018).
 Morad Veisi, “The Appointment Of New IRGC Commanders Shows The Concerns Of Iran’s Ruling Clerics,” Radio Farda, May 18, 2019; “Academics, Students Warn Khamenei About Divide Between People And Government,” Radio Farda, January 2, 2020; Rym Momtaz, “1/ Why did Iran militarily escalate in the Gulf lately? Shooting down a US drone, seizing tankers, bombing Saudi oil infrastructure? …,” Twitter, January 3, 2020.
 “Iran-US hostilities: IRGC fires missiles at US troops in Iraq,” Rudaw, January 8, 2020; Michael Safi, Oliver Holmes, and Ghaith Abdul-Ahad, “Iran launches missiles at Iraq airbases hosting US and coalition troops,” Guardian, January 8, 2020.
 “Trump: News sanctions on Iran but U.S. ‘ready to embrace peace,’” CBS News, January 8, 2020.
 “Iranian commander vows ‘harsher revenge’ against U.S,” CBS News, January 9, 2020.
 Ali Alfoneh, “Esmail Qaani: the next Revolutionary Guards Quds Force commander?” American Enterprise Institute, January 11, 2012.
 Nawal Sayed, “Esmail Ghaani: Who is Qasem Soleimani Successor?” See News, January 3, 2020; “Treasury Targets Iranian Arms Shipments,” U.S. Department of Treasury, March 27, 2012; Alfoneh.
 “Khamenei Appoints Hardliner General to Replace Soleimani,” Radio Farda, January 3, 2020; Duz, Zehra Nuz, “Iran’s supreme leader names new commander of Quds Force,” Anadolu Agency, January 3, 2020.
 Parker and Noack; Alfoneh.
 For specifics, see “Sepah: Infographic,” IranWire; “The IRGC Quds Force,” IranWire, April 9, 2019; “Islamic Revolutionary Guard Corps (IRGC),” Counter Extremism Project, January 3, 2020.
 For additional contextualization, see Afshon Ostovar, “Qaani will hit the ground running. The IRGC is part of a broader system. It relies much less on individuals …,” Twitter, January 3, 2020.
 Khaled Yacoub Oweis and Ben Farmer, “Who is Esmail Qaani, the new Iranian elite force commander?” National, January 3, 2020; Alfoneh.
 Knights, “Does Soleimani’s Death Matter?;” Nakissa Jahanbani, “What Iran Foreign Secretary’s Attempted Resignation Reveals About Today’s Iranian Politics,” Globe Post, April 5, 2019.
 Knights, “Does Soleimani’s Death Matter?;” Parker and Noack.
 Knights, “Does Soleimani’s Death Matter?”
 Ben Hubbard and Hwaida Saad, “Lebanon Elections Boost Hezbollah’s Clout,” New York Times, May 7, 2018; Renad Mansour, “Why Are Iraq’s Paramilitaries Turning on Their Own Ranks?” Washington Post, February 18, 2019; Michael Knights, “Iran’s Expanding Militia Army in Iraq: The New Special Groups,” CTC Sentinel 12:7 (2019).
 “Hezbollah head says gov’t fall could push Lebanon into ‘chaos,’” Al Jazeera, October 25, 2019.
 Oula A. Alrifai, “The ‘Rebuild Syria’ Exhibition: Iranian Influence and US Sanctions,” Washington Institute, September 17, 2019; Oula A. Alrifai, “What Is Iran Up To in Deir al-Zour?” Washington Institute, October 10, 2019.
 Suadad al-Salhy, “Revealed: How Iran led brutal suppression of Baghdad protests,” Arab News, October 23, 2019; Michael Knights, “Exposing and Sanctioning Human Rights Violations by Iraqi Militias,” Washington Institute, October 22, 2019; “Exclusive: Iran-backed militias deployed snipers in Iraq protests – sources,” Reuters, October 17, 2019.
 Joseph Felter and Brian Fishman, “Iranian Strategy in Iraq: Politics and ‘Other Means,’” Combating Terrorism Center, October 13, 2008, pg. 6-8.
 Ibid., pg. 8-10, 83-86; James Risen, Tim Arango, Farnaz Fassihi, Murtaza Hussain, and Ronen Bergman, “A Spy Complex Revealed,” Intercept, November 18, 2019.
 Nancy Ezzeddine, Matthias Sulz, and Erwin van Veen, “The Hashd is dead, long live the Hashd!” Clingendael Institute, July 2019; Renad Mansour and Faleh A. Jabar, “The Popular Mobilization Forces and Iraq’s Future,” Carnegie Endowment, April 2017; Knights, “Iran’s Expanding Militia Army in Iraq.”
 Garrett Nada and Mattisan Rowan, “Pro-Iran Militias in Iraq,” Wilson Center, April 27, 2018; Abdullah Almousa, “Front lines to watch for upcoming battles in Syria,” Daily Star (Lebanon), February 11, 2017; Christy Cooney, “FIRST STRIKE How Iran could cripple US in the Middle East by using bloodthirsty jihadi militias armed with war drones and deep sea mines,” Sun (UK), May 22, 2019; Michael Pregent, “Countering Iranian Proxies in Iraq,” House of Representatives Committee on Foreign Affairs, September 26, 2018; “Iraqi Militant Dragged into Iranian Proxy War in Syria Claims being Deceived,” Asharq Alawsat, August 11, 2017.
 Inna Rudolf, “From Battlefield to Ballot Box: Contextualising the Rise and Evolution of Iraq’s Popular Mobilisation Units,” ICSR, 2018, pg. 20.
 Knights, “Iran’s Expanding Militia Army in Iraq.”
 “Who was Abu Mahdi al-Muhandis?” Middle East Eye, January 3, 2020.
 Ibid.; Matthew S. Schwartz, “Who Was The Iraqi Commander Also Killed In The Baghdad Drone Strike?” NPR, January 4, 2020.
 “Who was Abu Mahdi al-Muhandis?;” Schwartz.
 “Who was Abu Mahdi al-Muhandis?”
 Knights, “Iran’s Expanding Militia Army in Iraq.”
 Knights, “Exposing and Sanctioning Human Rights Violations by Iraqi Militias;” al-Salhy.
 Bryce Loidolt, “Iranian Resources and Shi`a Militant Cohesion: Insights from the Khazali Papers,” CTC Sentinel 12:1 (2019); “Sheikh Akram Al-Kaabi, Leader of Iraqi Pro-Iran Al-Nujaba Militia: ‘Our Response [To The U.S.] Will Not Be Only A Missile Attack… We Will Draw Closer to Them, And Surprise Them’; ‘Al-Hashd Al-Sha’bi Is Directly Subordinate To The Iraqi Prime Minister;’” MEMRI, February 20, 2019; “Hashed al-Shaabi: Muqtada al-Sadr’s presence alongside Ayatollah Ali Khamenei is a clear message to the Zionist regime,” Resalat, September 14, 2019.
 Richard Hartley-Parkinson, “Shia cleric activates powerful anti-US army after airstrike killed Iran general,” Metro (UK), January 3, 2020.
 Michael Knights and Frznd Sherko, “Can Asaib Ahl al-Haq Join the Political Mainstream?” Washington Institute, February 14, 2018.
 Knights, “Iran’s Expanding Militia Army in Iraq.”
 “US Sanctions Iraq’s Asaib Ahl al-Haq,” Asharq al-Awsat, January 3, 2020.
 “Iraq’s powerful bloc calls for withdrawal of US troops after Israeli attacks,” ABNA, August 27, 2019; Mamoon Alabassi, “With wave of strikes, Israel starts new phase in war on Iranian proxies,” Arab Weekly, August 31, 2019.
 Elizabeth McLaughlin, “Pentagon to deploy roughly 3,500 more troops to Middle East with others placed on alert status, amid tensions with Iran,” ABC News, January 3, 2020; Mustafa Salim, Missy Ryan, Liz Sly, and John Hudson, “In Major Escalation, American strike kills top Iranian commander in Baghdad,” Washington Post, January 3, 2020; Arwa Ibrahim, “Iraqi parliament calls for expulsion of foreign troops,” Al Jazeera, January 5, 2020.
 Katie Bo Williams, “Soleimani Strike Could Imperil US Troops in Iraq,” Defense One, January 3, 2020.
 David D. Kirkpatrick, “Conflict with Iran Threatens Fight Against ISIS,” New York Times, January 4, 2020.
 Jeff Seldin, “Iraqi Forces Trying to Keep Pressure on Islamic State,” Voice of America, January 6, 2020; “Iranian commander vows ‘harsher revenge’ against U.S,” CBS News, January 9, 2020.
 Phillip Smyth, “The Shiite Jihad in Syria and Its Regional Effects,” Washington Institute, February 2015; Parker and Noack; Soufan.
 Soufan; Nakissa Jahanbani, “Iran’s Regional Influence Spreads with Militia Recruitment in Afghanistan,” Globe Post, August 22, 2018.
 Phillip Smyth, “How Iran Is Building Its Syrian Hezbollah,” Washington Institute, March 8, 2016.
 Sirwan Kajjo and Mehdi Jedinia, “Report: Iran Forming All-Syrian Militia in Syria,” Voice of America, March 2, 2019.
 David Adesnik and Behnam Ben Taleblu, “Burning Bridge: The Iranian Land Corridor to the Mediterranean,” Foundation for the Defense of Democracies, June 2019; Risen, Arango, Fassihi, Hussain, and Bergman.
 “Senior Administration Officials on Terrorist Designations of The Al-Nusrah Front as an Alias for Al-Qaida in Iraq,” States News Service, December 11, 2012; Tim Lister, “How the U.S. and Iran found common interests in unlikely places,” CNN, March 3, 2015; “Israel intel boss, ‘Assad preparing to use chemical weapons’; Iran, Hezbollah & Syria forming ‘People’s Army’,” ANSA English Media Service, March 14, 2013; Karen DeYoung and Joby Warrick, “Iran and Hezbollah build militia networks in Syria, officials say,” Guardian, February 12, 2013.
 “Hizbullah militia strengthens its presence in Deri Ezzor through the Zine El Abidine Brigades,” Zaman Al Wasl, June 19, 2016; Smyth, “How Iran Is Building Its Syrian Hezbollah.”
 Aymmen Jawad Al-Tamimi, “Liwa al-Imam Zain Al-Abidain: Building a ‘Resistance’ in Eastern Syria,” Syria Comment, September 18, 2016; Alrifai, “What Is Iran Up To in Deir al-Zour?”
 Oula A. Alrifai, “Assad is growing stronger under Trump’s nonexistent Syria policy,” Washington Post, December 29, 2019; Ariane M. Tabatabai and Colin P. Clarke, “Iran’s Proxies Are More Powerful Than Ever,” Foreign Policy, October 16, 2019.
 David M. Halbfinger, “Syria Pullout by U.S. Tilts Mideast Toward Iran and Russia, Isolating Israel,” New York Times, December 20, 2018.
 Alrifai, “What Is Iran Up To in Deir al-Zour?”
 Ibid.; Knights, “Iran’s Expanding Militia Army in Iraq.”
 Alrifai, “What Is Iran Up To in Deir al-Zour?”
 Parker and Noack.
 “Hadi al-Ameri appointed as new leader of PMU,” Mehr News Agency, January 3, 2020; Shahrvand Daily, “#HadialAmeri, successor to #AbuMahdial-Muhandis, Vice President of the Iraqi Popular Mobilization Organization #HashdalShaabi,” Twitter, January 3, 2020, translated from Persian to English; Pregent.
 Parker and Noack.
 For additional contextualization, see Ostovar.