Abstract: The Islamic State may be driven out of Mosul in the coming months, which would effectively destroy the group’s pretensions of administering a caliphate in Iraq. But the Islamic State has vowed to fight on, and if the past is prologue, the group may eye an opportunity to regenerate in Diyala province, Iraq’s sectarian tinderbox. By escalating terrorist attacks against Shi`a targets there, the group could create a spiral of sectarian violence that it could exploit to make a comeback. The strategy almost worked a decade ago. After the U.S. surge cleared Islamic State of Iraq fighters from Anbar province, the group made significant gains in Diyala by carrying out a terrorist campaign against Shi`a targets designed to plunge the country deeper into civil war.
Mosul may be liberated from the Islamic State in the coming months, presenting Islamic State militants in Iraq with a new set of challenges, opportunities, and decisions. For insurgency-watchers pondering Iraq’s near-future, there may be value in focusing on Diyala province, named after the river by the same name that runs from eastern Baghdad to the Iranian border. Diyala is not unlike a time machine, offering a kind of glimpse into the future, even as the Islamic State had already transitioned back to an insurgency in the province by the start of 2016. Diyala also offers an intriguing window into the other war in Iraq against the Islamic State—the one being fought primarily by Iranian-backed Shi`a militias with practically no involvement of the U.S.-led Combined Joint Task Force–Operation Inherent Resolve (CJTF-OIR). The war in Diyala gives insight into what future counterinsurgency operations of the Iraqi state might look like in cross-sectarian, multi-ethnic areas if CJTF-OIR support is discontinued and Shi`a militias take the lead.
Diyala’s Role as a Base for the Insurgency
Since 2003,a Diyala province1 has served as a fallback location for the takfiri predecessors of the Islamic State—the Islamic State of Iraq (ISI) and before that al-Qa`ida in Iraq (AQI). As Diyala-based coalition interrogator Richard Buchanan noted in 2014, “The recovery and refit area for the Sunni insurgents was always Diyala province. The insurgents who were married moved their families there, and their wounded would be often moved there as well.”2 When the U.S. surge cleared Anbar in 2007, ISI fell back into Diyala and very nearly took over the entire province. In the second quarter of 2007, an average of 418 attacks hit Diyala each month, mostly against Shi`a targets, and the government lost its ability to expend more than two percent of its budget or to distribute salaries or food rations.3 In Baqubah, the provincial capital, ISI controlled the city center, and the U.S. military was forced to lead major urban combat operations to clear the city of ISI fighters.b
The attractiveness of Diyala to Sunni militant groups is partly geographic. Diyala is a hub, connecting many militant operating areas; Tarmiyah and other takfiri bases in southern Salah al-Din province lie to the west. The desolate Jallam Desert and Hamrin Mountain range lie to the north, providing access to northern Iraqi provinces and ultimately Syria. The violent, ethno-sectarian melting pots of Tuz Khurmatu and Kirkuk are to the north, linked to Baghdad by Highway 2, which runs through northern Diyala. In the south, Diyala wraps around the eastern Baghdad metropolitan area, including the key takfiri target of Sadr City, a largely Shi`a metropolis of two million people. Running down the Diyala River Valley (DRV) is the pilgrim route of Highway 5, which brings Shi`a visitors from Iran to Iraq and back throughout the year.
The terrain of Diyala also makes the province an ideal location for insurgents seeking to shelter from security forces. In most rural areas of Diyala, it is impossible to drive for more than two kilometers without meeting a canal or irrigation ditch, complicating counterinsurgency raids. The 90-kilometer Diyala River delta is lined with dense palm groves that extend for one to three kilometers on either side of the river, making this one of the largest rough-terrain corridors in Iraq, twice as big as the hard-to-secure palm groves between Ramadi and Fallujah. The river is sparsely bridged, presenting a serious obstacle to motorized security forces, but is easily traversed by small boat at dozens of points, making monitoring and interdiction difficult for security forces.4 For these reasons, the Islamic State and its predecessors have repeatedly built bases for fighters and their families north of the river in the remote groves of Diyala, a completely different concept from their nesting within pre-existing, semi-urban Sunni areas in Iraq.5 Rural Diyala is currently a true terrorist safe haven.
Equally important, the human terrain of Diyala is attractive to takfiri militant groups. Around a 60-percent majority of Diyala residents are Sunni Arabs and Sunni Turkmen, with the remainder split between Shi`a Arabs and Shi`a Turkmen (25 percent) and Kurds (15 percent).6 Sunni Arab majorities live in the provincial capital of Baqubah (population 627,000 in 2007) and the DRV farming districts of Muqdadiyah (population 248,000 in 2007).7 There are Shi`a majorities in Khalis (population 319,000 in 2007) and Balad Ruz (population 135,000 in 2007) districts (plus Abu Sayda subdistrict in Muqdadiyah). Iranian-backed Shi`a parties like Badr—formed by Iran during the Iran-Iraq War from Iraqi Shi`a prisoners of war and oppositionists—have worked hard since 2003 to wield disproportionate influence over the Sunni majority,8 cooperating with Kurdish allies to dominate the provincial council, governorship, and police force for all but six of the last 13 years.c Sunnis also fear that the demographic balance may be shifting slowly against them through displacement by unstable conditions, Shi`a militia harassment, and drought.d In 2013, Diyala’s main Sunni bloc ran its provincial election campaigns on the theme of an “existential” threat detailed in a Shi`a militia campaign to “exterminate the people of Diyala.”9 Meanwhile, the Kurds claim the right to evict Sunni settlers brought by Saddam Hussein’s regime into northern Diyala areas like Jalula, Saadiyah, Qara Tapa, and Mandali.10 These identity issues have worked to sustain recruitment by Sunni insurgent groups like AQI/ISI, the Islamic Army of Iraq (IAI), 1920s Revolution Brigades, Hamas al-Iraq, Ansar al-Sunna, and the neo-Ba’athist Jaysh Rijal al-Tariqa al-Naqshbandia (JRTN) and Al-Awda (Return) groups.11 e
Nonidentity-based human terrain factors have also favored militant groups in Diyala. The eastern parts of the province, such as Muqdadiyah and Balad Ruz districts, are exceedingly poor, with 51 percent and 48 percent of households falling into the lowest wealth quintile in Iraq (compared to a national average of 21.7 percent).12 The Sunni tribes, regularly brought in since the 1970s to service the government’s newly irrigated farmlands, are smaller and more fragmented than in Anbar, rural Kirkuk, Salah al-Din, or Nineveh. Most rural families are highly dependent on irrigation systems and the generators that power them, a factor that insurgents have frequently exploited.13 The harvesting cycles in Diyala have also made it very easy for strangers to come and go without notice, blending into the inflow and outflow of seasonal agricultural workers.f All these socio-economic conditions have made it relatively easy for insurgents to control Diyala’s rural populations.
Why Didn’t the Islamic State Capture Diyala?
With all these circumstantial factors in the Islamic State’s favor, it might be intuitive to ask why the movement failed to overrun the security forces in Diyala completely in 2014. The provincial capitals of other Sunni Arab-majority provinces—Mosul, Ramadi, Tikrit—were all captured by the group and held for sustained periods, but not Baqubah. Likewise the Iraqi Army divisions in Nineveh, Kirkuk, and Salah al-Din collapsed entirely but not the 5th Iraqi Army division in Diyala. What accounts for the difference, and how does the explanation impact the Islamic State’s future in Diyala?
One cluster of factors relate to the Islamic State’s low starting base of operations in Diyala when Mosul fell in June 2014. In comparison to Nineveh, where there was an average of 347 security incidents per month in the first five months of 2014, there were only 71 per month in Diyala.14 In the week before Mosul fell, there were a staggering 208 attacks versus 32 in Diyala.15 As RAND’s extensive study of captured ISI documents noted, Diyala was only periodically a priority for AQI/ISI: it generated no funds and was, in fact, a net drain on the budget.16 The province is far from Syria, from where the Islamic State staged and supported its attack on Mosul.17 Moreover, the Islamic State did not have a good level of control over its most dangerous adversaries in the province—other insurgent groups. There are solid indications that the Islamic State was still actively fighting Ansar al-Sunna and JRTN elements in the summer of 2014,18 even as these groups maintained uneasy truces with the Islamic State or were defecting to the Islamic State in other provinces.
But a more important factor was the level of resistance the Islamic State faced from Shi`a paramilitaries and the Kurdish peshmerga. This tough resistance was lacking in nearby rural Kirkuk, where five Arab-populated districts fell to very small Islamic State patrols because the 12th Iraqi Army division had disbanded without a fight. In Diyala, the resisting power of the 5th Iraqi Army division was bolstered by the strong cadre of Badr commanders in the force and by the existing presence of major Shi`a militia forces in the province such as Badr, Asaib Ahl al-Haq (League of the Righteous, AAH), Kata’ib Hezbollah (KH), Moqtada al-Sadr’s Saraya al-Salam (Peace Companies), and Sayyid al-Shuhada.19 From June 13, 2014, Prime Minister Nouri al-Maliki appointed Badr leader Hadi al-Ameri as the provincial security chief in Diyala. Reinforcements from Badr and special forces units of the army and Ministry of Interior quickly reached al-Ameri at his base in Camp Ashraf, north of Baqubah.20 Iran also provided direct military support to the Iraqi and Kurdish security forces in Diyala, extending a security zone 50 kilometers into Iraqi territory and flying dozens of Iranian Air Force F-4E Phantom and Su-25 close-air support missions in support of the Hashd al-Sha’abi (Popular Mobilization Forces, PMF).21 These forces successfully limited the expansion of Islamic State control in Diyala.
The Islamic State briefly threatened the western side of the capital Baqubah—the newer and poorer residential areasg like Gatun, Muallimeen, and Mafraq—on June 17, 2014, with Iraqi SWAT teams carrying out the preemptive execution of around 50 detainees when insurgents threatened to overrun the Mafraq police compound.22 In Buhriz, to the south of Baqubah city, insurgents overran and held the local police station for several hours before being pushed out by Shi`a militiamen supported by Iraqi Army Aviation Mi-35 helicopters. The clearance of Buhriz was accompanied by the torching of civilian houses and mosques, the execution of up to 30 military-aged males, and the displacement of much of the local population.23 Outside Baqubah, the scattered 5th Iraqi Army division forces and PMF units secured Khalis and regained contact with all the DRV towns by early July.24
The Islamic State seems to have concentrated its efforts in northern Diyala, specifically the towns “Arabized” by the Saddam Hussein regime such as Jalula, Saadiyah, and Qara Tapa, within what ISI called the Azim sector.h In the spring of 2014, the Islamic State was clearly preparing to evict Iraqi Army forces from these areas, readying the battlefield in a manner similar to its lead-up to the Mosul offensive. These shaping operations included attacking bridges with car bombs in order to obstruct security force reinforcement of the area; use of platoon-sized assaults to overrun police stations; and larger assaults on headquarters involving very large, water-tanker suicide VBIEDs and follow-on infantry assaults.25 Much of the Islamic State’s reinforcements in Diyala in 2014 seems to have been fed into the northern fight against the Kurds for control of Jalula, which the Islamic State seized in a massive deliberate assault on August 11, 2014, that employed 20 suicide vest bombers. This northern preference seems to have been based on the Islamic State’s alliance with local tribes in the Lake Hamrin area, arguably the only place in Diyala where AQI/ISI and later the Islamic State maintained a strong, pre-existing base of support in 2014. When Kurdish forces moved forward to replace a collapsing Iraqi security forces (ISF) presence in late June and July, the Islamic State quickly struck deals with anti-Kurdish Sunni tribes such as the Kerwi and strongly supported a joint operation against the Kurds.i
Islamic State Regeneration since 2015
Between the fall of Mosul in June 2014 and January 2015, the Iraqi Army and various Shi`a militias working under the rubric of the Hashd al-Sha’abi (Popular Mobilization Forces, or PMF) recaptured territory in Diyala. In January 2015, the Tigris Operations Command declared the liberation of Diyala province.26 But Badr’s “mission accomplished” moment in Diyala only marked the beginning of a new phase of the local conflict with the Islamic State and one in which the insurgents have partially regained the initiative. The Islamic State has fallen back into the ungoverned spaces of Diyala: the dense palm groves of the DRV between Muqdadiyah and Baqubah; the inhospitable wastes of the Iranian border; and the Hamrin Mountains, where parallel striations, or ridgelines, greatly slow motorized security forces, giving insurgents plenty of time to relocate or set ambushes.
The Islamic State’s use of historic Diyala River delta bastions such as Zaghaniyah, Qubbah, Mukhisa, and Abu Karmah is particularly problematic for the security forces. In the riverside groves to the north of these areas, the Islamic State has returned to the old AQI/ISI habit of creating major defensive bunker complexes, bomb-making factories, supply points, and training camps.j In August 2015 insurgents extended their presence into the DRV groves south of Baqubah, with IED cells operating from bastions on the west bank of the Diyala River between Baqubah and Khan Bani Saad.27 The Islamic State is increasingly hard to ignore in these areas because they are using the groves to launch an escalating drumbeat of effective IEDsk and mortar strikesl on local villages and security outposts and, lately, also larger assaults on outposts and fixed checkpoint positions. In the first of many similar assaults, an ISF outpost in the groves near Muqdadiyah was attacked on July 15, 2015, by a platoon-sized Islamic State cell in a sustained engagement that lasted for several hours.28 By December 2015, platoon-sized Islamic State fighting cells were conducting night raids on ISF in the Buhriz area, just four kilometers south of the provincial capital.m By October 2016, DRV towns like Qubbah and Abu Karmah were being isolated by Islamic State patrolling and snap checkpoints, a potential precursor to an overrun.29
The Badr-led security effort in Diyala has struggled to come to grips with the Islamic State rural bastions. Some areas such as the Mandali and Nida areas on the Iranian border and the shores of Lake Hamrin appear to have been yielded to the insurgents, and ISF only goes in temporarily during ineffective clearance operations.30 The groves around Mukhisa—dubbed the “Kandahar of Diyala” by local security officials 31—have been the scene of painful, IED-initiated ambushesn against ISF patrols attempting to push into the bush. The Tigris Operations Command is bulldozing and burning back the ancient palm groves to protect better the extension of fixed security checkpoints and patrols along the roads.o Retaliation against the local Sunni population has been a regular occurrence over the last three years 32 and is likely to increase as Iraqi Army and PMF frustrations and casualties grow.p
A Strategic Terrorist Campaign
The Islamic State may not place much priority on the control of Baqubah and southern Diyala, but the movement will find the province immensely useful if it wishes to resurrect the idea of fomenting a Shi`a-Sunni war in Iraq by drawing sectarian retaliation onto the Sunnis and driving them toward the Islamic State for protection. This was Abu Musab al-Zarqawi’s specific intent in his February 2004 letter to Ayman al-Zawahiri.33 The Islamic State has already begun to bait Badr and the PMF with local car bombings. VBIEDs have targeted Shi`a civilians and PMF in Baqubah, Khalis, Muqdadiyah, and also in the Shi`a-majority agricultural towns of Balad Ruz and Kan’an. Such attacks can be highly lethal; on July 17, 2015, a massive ice truck VBIED hit a market in Khan Bani Sa’ad, killing over 120 Iraqis.34 The Islamic State has also upped its attacks on electricity transmission pylons and gas pipelines that are intended to increase Baghdad’s power supply.q
Mass-casualty attacks are effective in stirring local sectarian and tribal tensions in cross-sectarian areas like Diyala. Following a January 11, 2016, double bombing in a café in Muqdadiyah that killed over 46, including a local Badr commander, roving bands of Badr and Asaib Ahl al-Haq (AAH) fighters cruised the city, using loudspeakers to call on Sunni families to leave or face execution. Militiamen also torched Sunni-owned shops and houses and firebombed seven Sunni mosques, despite the curfew in place and the deployment of Diyala police reinforcements.35 Another suicide bombing of a Shi`a militia funeral in a village outside Muqdadiyah in February 2016 resulted in over 50 fatalities, including several AAH and Badr commanders. The attack was followed by clashes between police and militias at the Muqdadiyah police headquarters when militiamen attempt to storm the jail and execute detainees.36
The Islamic State has also used Diyala as a base to launch attacks on Baghdad, particularly Shi`a-majority east Baghdad, which is accessible at multiple points from Balad Ruz and Baqubah districts.r On July 3, 2016, a suicide car bomb detonated in front of a shopping mall in Baghdad’s Karrada peninsula, sparking a fire that killed over 300 Iraqis, one of the deadliest single attacks in Iraq since 2003.37 The Iraqi Ministry of Interior indicated the car bomb had been constructed in Diyala and passed through a checkpoint near Khalis before driving on to Baghdad. A wave of three car bombs in Sadr City and east Baghdad in early May 2016 was also traced back to Diyala.38 If further car bombings spark sectarian reprisals in Baghdad or elsewhere, or skew the shape of sectarian politics and electioneering or security force appointments, then the Islamic State may be able to quickly move past its battlefield defeats with a highly consequential strategic terrorist campaign.
The Future of the Islamic State in Diyala and in Iraq
The Islamic State would undoubtedly prefer to control Mosul, Ramadi, Fallujah, or Tikrit than rural Diyala, but the group is rapidly being denied that option. Diyala has always been a fallback, a place to hide and recover, which suits exactly the Islamic State’s current needs. The exclusion of coalition forces from Diyala due to Badr’s stranglehold on the Tigris Operations Command will make it far harder for ISF to penetrate the Islamic State’s rural bastions, which historically required U.S. intelligence, surveillance, and reconnaissance plus special operations, precision-strike capabilities, and local Sunni militias. Without determined sectarian and ethnic peace-building efforts, the identity politics of Diyala will keep the Islamic State and allied movements stocked with recruits in the years to come and deny the security forces vital intelligence on the enemy.
Neither Badr nor the Kurds seem likely to adopt effective counterinsurgency approaches such as the reconciliation and Sunni empowerment initiatives that suppressed AQI/ISI in Diyala in 2007-2009. In May 2015, the pan-Shi`a and Kurdish blocs colluded with some Sunni factions to replace the Sunni provincial governor Amer al-Majmais with Badr’s own Muthanna al-Tamimi, a Shi`a politician.39 Though Badr has offered to support a Sunni provincial governor after new local elections (due in 2017),40 the likelihood is that Badr will continue to dominate local politics and security. Where Sunnis feel divided and powerless in the political sphere, the lure of armed opposition will grow.
Badr has various options if it seeks to secure the support of Diyala’s fractured Sunni population. Albeit for its own factional motives, Badr is starting to crack down on rival militia AAH,t the militia most regularly linked to sectarian massacres, criminal rackets, and highway checkpoint shakedowns.u Hadi al-Ameri has also splintered and co-opted some Sunni tribes by facilitating—or withholding—the return of internally displaced persons to their homes.v Badr is also allowing some returned tribes to serve as Hashd al-`Asha’iri (tribal mobilization forces) in order to penetrate Islamic State rural bastions.w But outside of these rural northern Diyala hotspots, Badr is still rejecting alliances with Sunni fighters. For instance, nearly 3,000 original pre-2011 Diyala “Popular Committee” fightersx have been demobilized since the fall of Mosul,41 suggesting Badr prefers to blanket Sunni areas with Shi`a militias rather than trust Diyala Sunnis with weapons. Unlike in other Sunni-majority provinces where Sunni leaders command the Hashd forces, the Diyala PMF are led by provincial councilman Qasim al-Maamuri, a Shi`a ally of Badr.42 The Kurds do not allow any Arab paramilitary forces in the areas they control and have even stated that no members of the Kerwi tribe, which backed the Islamic State, will be allowed to return to Jalula.y
Diyala offers a look into the near-future of Iraq’s security situation in areas where ethno-sectarian tensions are neglected or even exacerbated by government policies and the presence of uncontrolled militias. The Islamic State’s partial regaining of the initiative, very quick recovery, and transition back toward insurgency and strategic terrorism in Diyala is instructive, though it may not be matched in other provinces due to the unique mix of geography and human terrain in each Iraqi governorate. If Diyala continues on its present path, it is likely to become the Islamic State’s main safe haven location in Iraq, back-to-back with other key operational locations like Tarmiyah, the Jallam Desert, the Hamrin Mountains, the Iranian border, and the eastern approaches to Baghdad.
Michael Knights, a Lafer Fellow with The Washington Institute for Near East Policy, has worked in all of Iraq’s provinces, including periods spent embedded with Iraqi security forces. His latest study is the Washington Institute report “The Long Haul: Rebooting U.S. Security Cooperation in Iraq.” Follow @mikeknightsiraq
Alex Mello is lead Iraq security analyst at Horizon Client Access, an advisory service working with global energy companies. Follow @AlexMello02
[a] Use of the term takfiri in this article refers to Sunni insurgent groups that justify violence against some Muslims and all non-Muslims because their religious beliefs are not compatible with their groups’ ideology. Key takfiri groups in Iraq include the Islamic State, Islamic Army of Iraq, and Ansar al-Sunna/Ansar al-Islam.
[b] Operation Arrowhead Ripper, launched on June 18, 2007, was the culminating point. See Kimberly Kagan, “The Battle for Diyala,” Iraq Report IV, Weekly Standard, May 7, 2007.
[c] A good example is Diyala police chief Ghanem al-Qurayshi, a Badr-affiliated former military officer who worked from 2005-2008 to reduce Sunni involvement in local security forces. See Dahr Jamail, “‘Provincial Saddam’ Goes, Finally,” Inter Press Service, August 14, 2008. At the district level, the situation was no better. The Muqdadiyah police chief, another Badrist, ran an extensive car stealing and arrest extortion racket that principally targeted local Sunnis. See Joel Wing, “How Iraq’s Civil War Broke Out In Diyala Province: Interview With Former Interrogator Richard Buchanan,” Musings on Iraq, July 28, 2014.
[d] It should be noted that Shi`a have an equally justified fear that Sunni militants are trying to cleanse them from the province.
[e] The author received a detailed map-aided briefing on concentration levels in the insurgent areas of control. AQI/ISI dominated in western and northern Baqubah, the Hamrin area, Iranian border areas, and the groves of the DRV. Ansar al-Sunna had strongholds near Balad Ruz. The other former regime and Iraqi takfiri groups were mainly located in eastern Baqubah (where there were Republican Guard communities) and in Muqdadiyah and Hamrin.
[f] The province is the center of citrus and date farming in Iraq and is a major producer of cereals.
[g] These areas were historically strong AQI/ISI operating areas, adjacent to the ISI Tarmiyah sector on the west side of the Tigris and next to Hibhib, where Abu Musab al-Zarqawi was killed in 2006.
[h] This refers to Uzaym/Udaim, a river running parallel to the Diyala, including Udaim town and dam, Qara Tapa, and Deli Abbas, a key launch-pad location within the Diyala River delta north of Muqdadiyah. See Patrick B. Johnston, Jacob N. Shapiro, Howard J. Shatz, Benjamin Bahney, Danielle F. Jung, Patrick Ryan, and Jonathan Wallace, Foundations of the Islamic State: Management, Money, and Terror in Iraq, 2005–2010 (Santa Monica, CA: RAND Corporation, 2016), pp. 85-89.
[i] The Kerwi tribesmen are long-time inhabitants of the Lake Hamrin area and include a high proportion of former military officers as well as farmers. “Diyala Governor Splits Sunnis to Defeat Impeachment Bid,” Inside Iraqi Politics 134.
[j] In August 2015, ISF cleared a large insurgent training camp, refit and support base, and IED-manufacturing site deep in the groves near Mukhisa. See Ali Salem, “Diyala destroys the camp Zarqawi used to recruit and train extremists,” New Sabah, August 21, 2015.
[k] In a recent example on January 11, 2016, Islamic State fighters infiltrated across the Diyala River from Sherween (north of Abu Sayda) to set up two daisy-chained roadside IEDs that were used against a Sunni tribal militia working with the ISF, wounding one fighter. All incident data is drawn from the authors’ geolocated Significant Action (SIGACT) dataset. The dataset brings together declassified coalition SIGACT data plus private security company and open-source SIGACT data used to supplement and extend the dataset as coalition incident collection degraded in 2009-2011 and was absent in 2012-2014.
[l] These are typically mortar salvos of five to seven rounds that appear to be carefully surveyed. Firing against static and unprotected targets like checkpoints or civilian villages, the attacks frequently cause fatalities and multiple injuries. Authors’ SIGACT dataset.
[m] An Islamic State photo report released in December 2015 showcased the operations of a platoon-sized Islamic State unit in the Buhriz area raiding the houses of ISF personnel and carrying out battlefield extrajudicial killings. See imagery in “IS’ Diyala Province Releases Photo Report on Raiding Enemy Sites in Buhriz,” SITE Intelligence Group, December 2, 2015.
[n] In another recent example on July 12, an ISF patrol on a rural road four kilometers east of Mukhisa was hit with an IED and engaged with small-arms fire from insurgents in groves. Authors’ SIGACT dataset.
[o] In May 2016, the Tigris Operations Command began implementing a new security plan for the area supported by the deployment of provincial SWAT units from Baghdad and Wasit, pushing new roads into the groves along the Diyala River, setting up new fixed checkpoints on the farm roads linking the villages, and stepping up patrolling. See “Security forces in Diyala open road amid orchards to control the areas Daesh,” Alhurra Iraq, available on Youtube.com, May 17, 2015.
[p] In the first three quarters of 2016, the number of openly reported ISF and PMF casualties in frontline fighting in Muqdadiyah district were 40-50 killed and 80-90 wounded. Diyala is less open to journalists than other parts of Iraq, and considering that ISF casualties are generally underreported, the above numbers likely represent a half or a third of actual security force casualties. Authors’ SIGACT dataset.
[q] Since 2013, the Islamic State has carried out a persistent multi-year campaign on electricity pylons carrying Iranian voltage to Iraq and more recently has struck Iranian pipeline crews working on a pipeline to bring Iranian gas to Diyala power stations (and eventually to Baghdad). On December 13, 2013, 15 Iranians were shot dead along with three Iraqis in one such attack on pipeline teams. More recently, ISF captured an Islamic State cell on April 26, 2016, in Imam Ways (north of Muqdadiyah) involved in IED attacks on pylons and repair crews. Authors’ SIGACT dataset.
[r] Along with the Tarmiyah area just north of Baghdad city, the Baghdad Operations Command views Diyala as the chief source of the car bomb threat against the capital. Author (Knights) interview, Baghdad security official, 2016.
[s] Al-Majmai was himself a puppet of the Shi`a parties in Baghdad, replacing another Sunni governor, Omar al-Humayri, ousted by a Badr-led intrigue. The authors wish to thank Kirk Sowell and Nate Rabkin of the Inside Iraqi Politics team for their outstanding work on the collation and analysis of political trends in Diyala.
[t] On September 21-26, 2016, Badr paramilitaries and AAH paramilitaries were fighting for control of the sub-district center of Abu Sayda. In Tuz Khurmatu, meanwhile, Badr moved against AAH locations within the town. Authors’ SIGACT dataset.
[u] For example, on February 23, 2013, leaflets signed by AAH threatened families living in Muqdadiyah unless they left their homes in 48 hours. Authors’ SIGACT dataset.
[v] Badr leader Hadi al-Amiri personally accompanied 400 Sunni families returning to Mansouriyah in May 2016. See “Diyala Governor Splits Sunnis to Defeat Impeachment Bid,” Inside Iraqi Politics 134, July 11, 2016.
[w] Badr seems to have made good progress with the Azzawi tribe, a major grouping in the Hamrin and Muqdadiyah area, with the Tigris Operations Command nominally led by an Azzawi figure, Major General Muzhir al-Azzawi. Jabbouri confederation Hashd al-Asha’ir fighters also work with Badr in northern Diyala, as they do in the Tikrit and Kirkuk areas.
[x] This was the highly successful Diyala version of the “Sahwa” (Awakening). Numerous Sunni paramilitary volunteer groups flipped from anti-coalition insurgency to anti-AQI/ISI operations in 2007-2009. For a useful reference, see Multi-National Division–North PAO Press Release No. 20061210-09, “Sheiks continue discussions of security, stability for Diyala,” Dec. 10, 2006, and Multi-National Division–North PAO, “Sheiks sign peace agreement,” May 3, 2007.
[y] The Kerwi are the largest Sunni tribe in Jalula, and Diyala’s elected Provincial Council Chairman, Omar al-Kerwi, is from this tribe. Inside Iraqi Politics 134.
 For primers on Diyala, see Eric Hamilton, “Expanding Security in Diyala,” Institute for the Study of War, August 2008; Kimberly Kagan, “The Battle for Diyala,” Iraq Report IV, Weekly Standard, May 7, 2007; and Michael Knights, “Pursuing Al-Qaeda into Iraq’s Diyala Province,” CTC Sentinel 1:9 (2008).
 Joel Wing, “How Iraq’s Civil War Broke Out In Diyala Province: Interview With Former Interrogator Richard Buchanan,” Musings on Iraq, July 28, 2014.
 A very sharp picture of AQI/ISI’s near-victory and the total loss of government control is given in Patrick B. Johnston, Jacob N. Shapiro, Howard J. Shatz, Benjamin Bahney, Danielle F. Jung, Patrick Ryan, and Jonathan Wallace, Foundations of the Islamic State: Management, Money, and Terror in Iraq, 2005–2010 (Santa Monica, CA: RAND Corporation, 2016), pp. 35, 50.
 Wing, “How Iraq’s Civil War Broke Out In Diyala Province.”
 For a detailed account of AQI’s takeover of the rural Diyala River villages in 2006-2007, see James Few, “The Break Point: AQIZ Establishes the ISI in Zaganiyah,” Small Wars Journal, April 17, 2008.
 See Knights, “Pursuing Al-Qaeda into Iraq’s Diyala Province” and Annex 5 on 2005 provincial election results in Michael Knights and Eamon McCarthy, “Provincial Politics in Iraq: Fragmentation or New Awakening?” Washington Institute for Near East Policy, 2008.
 “Iraq Household Socio-Economic Survey,” Comprehensive Food Security and Vulnerability Analysis (CFSVA), Central Organization for Statistics & Information Technology (COSIT), and United Nations World Food Programme, 2008, pp. 129-136.
 For a summary of Badr’s long involvement in Diyala, see Michael Knights, “Iraq’s Bekaa Valley,” Foreign Affairs, March 16, 2015.
 “Shift to Extreme Polarization Continues,” Inside Iraqi Politics 83, April 19, 2014, p. 2.
 For a good explanation on the parts of Diyala claimed by the Kurds, see Sean Kane, “Iraq’s Disputed Territories: A View of the Political Horizon and Implications for U.S. Policy,” U.S. Institute for Peace, 2011.
 Author (Knights) interview, Iraqi intelligence officers, Diyala province, 2011.
 “Iraq Household Socio-Economic Survey,” pp. 130-132.
 A good summary of trends can be found in “The Water Wars Waged by the Islamic State,” Stratfor, November 25, 2015.
 All incident data is drawn from the authors’ geolocated Significant Action (SIGACT) dataset. The dataset brings together declassified coalition SIGACT data plus private security company and open-source SIGACT data used to supplement and extend the dataset as coalition incident collection degraded in 2009-2011 and was absent in 2012-2014.
 Authors’ SIGACT dataset.
 Johnston et al., pp. 20-22.
 Ned Parker, “Special Report: How Mosul fell – An Iraqi general disputes Baghdad’s story,” Reuters, October 14, 2014.
 An excellent collation of open-source articles on these intra-insurgent clashes is provided in Joel Wing, “Iraq’s Diyala Province An Insurgent Stronghold,” Musings on Iraq, February 2, 2015.
 For an excellent breakdown of these groups, see “Appendix 5: Iraq’s New Iranian-Influenced/Proxy Militias” in Phillip Smyth, “The Shiite Jihad in Syria and Its Regional Effects,” Policy Focus 138, Washington Institute for Near East Policy, February 2015.
 Susannah George, “Breaking Badr,” Foreign Policy, November 6, 2014.
 David Cenciotti, “Previously unknown details about Iranian F-4, F-5, Su-24 and UAVs involvement in air strikes on ISIS targets in Iraq,” Aviationist, December 4, 2015.
 Ahmed Ali, Heather L. Pickerell, and ISW Iraq Team, “ISW Iraq Situation Report,” June 17, 2014; “Iraq conflict: Clashes on approaches to Baghdad,” BBC, June 17, 2014; Oliver Holmes, “Sunnis accuse Iraq forces of jailhouse massacre,” Reuters, June 19, 2014.
 Ned Parker, Ahmed Rasheed, and Raheem Salman, “Sectarian strife threatens Iraq ahead of election,” Reuters, April 27, 2014; Ghaith Abdul-Ahad, “Iraq election holds little hope of change for town scarred by decade of war,” Guardian, April 29, 2014.
 Ghaith Abdul-Ahad, “Iraq: on the frontline with the Shia fighters taking the war to Isis,” Guardian, August 24, 2014.
 Matt Bradley and Ali A. Nabhan, “Fledgling Iraqi Military Is Outmatched on Battlefield,” Wall Street Journal, May 1, 2014.
 Wing, “Iraq’s Diyala Province: An Insurgent Stronghold.”
 “Diyala governor pushes for ‘quick solutions’ to curb the killings and set up improvised explosive devices in the village of Bani Saad,” Almada Press, August 22, 2015.
 Authors’ SIGACT dataset.
 “A mortar shell fell on the farming village northeast of Baquba,” Al Sumaria, October 3, 2016.
 For a good characterization of ISF’s missteps in the Lake Hamrin area, see “Badr’s Bid to Lead Shia Camp Struggles in Diyala, Tuz,” Inside Iraqi Politics 130, pp. 5-6, June 20, 2015.
 `Ammar Tariq and Nida’ Fu’ad, “Amn Abi Sayda: Al-Makhisa Qandahar Diyala wala Nahtaj ila Athan Al-Siyasiyyin li Darb Al-Irhab,” Al-Sumaria, April 19, 2014, http://www.alsumaria.tv/news/98297/#
 A thorough collation of ISF and PMF atrocities in Diyala can be found in Wing, “Iraq’s Diyala Province: An Insurgent Stronghold.” For a close look at early 2014 atrocities, see “Low-Level Sectarian Violence Defies Reconciliation Efforts,” Inside Iraqi Politics 78, February 3, 2014, p. 8.
 A translation of this letter is available on the U.S. State Department website.
 Kevin Conlon, Jason Hanna, and Mohammed Tawfeeq, “Iraq ice truck bombing kills 120,” CNN, July 19, 2015.
 A good summary of the events in Muqdadiyah is available in Joel Wing, “Iraq’s Diyala Province Explodes in Sectarian Violence after Islamic State Bombing,” Musings on Iraq, January 14, 2015.
 “Iraq crisis: Suicide bomb kills 38 at Shia funeral,” BBC, February 29, 2016.
 Ali A. Nabhan and Karen Leigh, “Death Toll from Sunday Baghdad Bombing Nears 300,” Wall Street Journal, July 7, 2016.
 “Kayfa Dakhalat Al-Sayyarah Al-Mufakhakha ila Madinat Al-Sadir?” Al-Mu`alimmah, May 11, 2016.
 “Militia Clashes Raise Issue of Stability in Liberated Areas,” Inside Iraqi Politics 111, pp. 4-5, May 21, 2015; “Sunni Provincial Leaders Emasculated,” Inside Iraqi Politics 112, pp. 5-7, June 20, 2015.
 “Awakening warns of absence for its fighters in Diyala area,” Al Sumaria, July 5, 2016.
 “Diyala: Militias Push for More Professional Organization,” Inside Iraqi Politics 94, October 21, 2014, p. 4.