The Islamic State in Iraq and the Levant (ISIL) has the world on edge. Since its nadir in the spring of 2010, ISIL is considered to have evolved from a terrorist group on-the-ropes to “a full-blown army,” in the words of U.S. Deputy Assistant Secretary of State for Near Eastern Affairs Brett McGurk. As the Institute for the Study of War noted, ISIL’s overall strategy of consolidating and expanding its caliphate “fundamentally relies upon military superiority to wrest control of land and cities from modern states.”
An analysis of ISIL’s recent military accomplishments is difficult due to the lack of confirmed facts about much of what has transpired in Iraq, particularly during the hectic months since the collapse of federal security forces in Mosul on June 10, 2014. Questions still remain over the actual contribution that ISIL made to the loss of federal control and over the mix of ISIL and non-ISIL forces fighting since June. Nevertheless, using a range of case studies from the Iraqi side of ISIL’s area of operations, this article explores what is currently known about the movement from a military standpoint. If ISIL is an army, what kind of army is it and what are its weaknesses?
This article finds that ISIL is a military power mostly because of the weakness and unpreparedness of its enemies. Lengthy shaping of the battlefield, surprise and mobility made its recent successes possible, but all these factors are diminishing. As a defensive force, ISIL may struggle to hold terrain if it is attacked simultaneously at multiple points or if its auxiliary allies begin to defect.
ISIL’s Multi-Year Offensive
ISIL’s successful offensive since June 2014 can only be understood by situating it in the broader context of its political-military campaigns since the organization “re-booted” under Abu Bakr al-Baghdadi’s leadership on May 15, 2010. ISIL did not suddenly become effective in early June 2014: it had been steadily strengthening and actively shaping the future operating environment for four years. As Brett McGurk noted in congressional testimony in February 2014, ISIL’s planning has been “sophisticated, patient and focused.”
The shattering of Iraqi security forces (ISF) in June 2014 is a case-in-point, the result of years of patient preparatory operations. Early in Abu Bakr al-Baghdadi’s tenure, the Islamic State of Iraq (ISI), the current group’s forerunner, began targeting pro-government Arabs in a powerful multi-year campaign of assassinations that culminated in al-Baghdadi’s “Soldiers Harvest” campaign against on-duty and off-duty security force members from July 29, 2013, to June 2014. In addition to demolitions of soldiers’ homes, the first six months of “Soldiers Harvest” witnessed a sharp 150% increase in the number of sophisticated close quarters assassinations of troops manning checkpoints and effective under-vehicle improvised explosive device (IED) attacks on key leaders.
Although the campaign was executed across Iraq, it was particularly focused on Mosul and Ninawa Province, including escalating efforts to cut off Mosul’s highway communications with Baghdad. By June 2014, according to McGurk, “by day [Mosul] would appear normal, but at night, ISIL controlled the streets.” When ISIL’s offensive began in Mosul on June 6, 2014, the ISF were brittle and comparatively easy to crumble during three days of escalating skirmishes within the city.
Alongside weakening the opposition, al-Baghdadi also used the years preceding this summer’s successes to build the current ISIL force. The U.S. withdrawal from Iraq and the Syrian civil war provided ISIL secure bases and a reinvigorated pipeline of suicide bombers. As analysts have noted, ISIL has developed a highly-motivated cadre of quality light infantry forces since 2012, drawing on the combat experiences of urban and mobile warfare in Syria, as well as from the prior combat experiences of foreign jihadists who served in the Balkans and Chechnya. These lessons have been institutionalized and refined in training camps in Syria and, since the first half of 2013, also in Iraq.
Trained fighters were increasingly shifted from Syria to Iraq from “early 2013” according to McGurk, and new camps were set up on the Iraqi side of the border complete with local anti-aircraft defenses that proved effective at deterring attacks from unarmored Iraqi helicopters. ISIL attacked Mosul on June 6, 2014, with the main strike force deployed from Syria in a motorized infantry column that included “hundreds” of armed utility vehicles. In all these cases, ISIL reinforcements from Syria joined up with local cells within Iraqi provinces that had already kept up a drumbeat of operations year after year. Based on the estimates from a range of experts, the number of fighters directly under ISIL’s control within Iraq may have reached as high as 10,000-15,000, “taking into account defections from other groups such as Jamaat Ansar al-Islam, “repentances” of security force members, and pledges of bay`a (loyalty).”
Abu Bakr al-Baghdadi’s tenure has also seen ISIL develop its own distinctive style of command and control. During the “Breaking the Walls” campaign (July 2012-July 2013), the then-ISI demonstrated and repeatedly exercised its re-centralized command and control system in 20 multi-city synchronized car bombing waves, a sequence of attacks that continued until the end of 2013. The bombings illustrated al-Baghdadi’s formula of centralized control but decentralized execution, with his command cell setting the date of the attacks but the regional wilayat (provinces) commanders setting their level of participation according to local conditions.
Offensive Operations in 2014
Surprise, mobility and shock are the principal characteristics of ISIL offensive operations in Iraq. The group often achieves tactical surprise, whether against the federal ISF or Kurdish forces. This is attained through rapid approach marches that utilize Iraq’s dense, high-quality road network and often culminate in night or dawn attacks. The relative compactness of Iraq, where good roads allow large swathes of the country to be traversed in a single day, gives an aggressive force strong ability to concentrate forces at a given point of attack. Mobility and deception allow ISIL forces to achieve local superiority in numbers despite their smaller strength in comparison to state armed forces, with aggressive platoon-sized or company-sized raiding columns defeating and dislodging successive ISF or Kurdish positions. Probes and feints appear to be common elements in ISIL offensives, often apparently intended to test opposition, bypass solid defenses, and draw away enemy forces from the main target. ISIL columns have the mobility to rapidly exploit any thinning of enemy forces, as occurred recently when ISIL struck Jalula on August 10, 2014, a town that Kurdish special forces had previously left to meet an ISIL thrust elsewhere at Makhmour. Lacking intelligence analysis skills, wide area surveillance capabilities, or local night vision aids, federal ISF and Kurdish forces are generally not aware of massing ISIL forces until it is too late.
Since the capture of significant stocks of ISF vehicles in June 2014, ISIL often attaches two to five wheeled armored vehicles to such columns for shock effect, in some cases causing “tank fear” when defending troops are of lower quality or lack anti-tank defenses. An early example of ISIL’s armored warfare in Iraq was its July 24, 2014, vehicle-mounted raid on the State Company for Pharmaceutical Supplies, five miles behind Kurdish lines northeast of Mosul city. The assault involved several ISIL 4×4 pickup trucks with mounted 12.7mm machine guns and at least three armored vehicles looted from ISF bases in Mosul. The raid overran the thin peshmerga (Kurdish militiamen) checkpoint screen on Highway 2 and then continued to exploit behind peshmerga lines for an additional five miles after reaching the pharmaceutical factory—a total penetration of 10 miles.
ISIL has also employed artillery barrages, although only in a small number of cases (such as the August 3, 2014, attack on Zummar and Kisik, west of Mosul). When ISIL uses artillery, it typically uses single artillery pieces or small arrays of 57mm rocket artillery and mortars—neither of which are particularly effective. On some occasions, heavy barrages have been recorded, notably at Zowiya (where a 500-round barrage was loosely estimated).
Instead, the heavy weapons most frequently employed by ISIL tend to be its traditional tools—the suicide or remote-detonated car bomb and the suicide vest. When seeking to panic and dislodge enemy troops, ISIL almost always begins its local offensives with one or more mass casualty attacks on enemy headquarters and checkpoints. These storming tactics have been practiced and developed from the earliest days of the ISI’s rebirth in 2010, when al-Baghdadi’s first Ramadan offensive began on June 29, 2010, with the breaching of a police checkpoint in Adhamiyah, allowing the ISI to plant its flag in central Baghdad during daylight hours. From the summer of 2011 onwards, these incidents became increasingly common and usually featured car bombs to create chaos and breach barriers, the attempted passage of suicide vest attackers and gunmen (often wearing security force uniforms) into the affected complexes, and hostage-taking to prolong the incident.
Although such opening gambits usually target one or two buildings with a small number of devices, these attacks are occasionally much larger. On August 11, 2014, ISIL launched an offensive into Jalula that commenced with an armored vehicle suicide car bomb on a peshmerga headquarters, killing more than 20 peshmerga fighters, and a second tanker truck suicide device in the town center, followed by individual suicide vest bombings on 12 checkpoints by fighters wearing Kurdish-style uniforms. Unsurprisingly, this onslaught shattered peshmerga morale and the town was lost.
ISIL also uses various types of exemplary violence, what Robert Scales and Douglas Ollivant termed “strategic killing,” to spook their military adversaries and drive out civilian populations. During the initial ISIL advance in June, the movement used social media (i.e., mainly Twitter) to spread the word that ISIL columns would give no quarter to resisters but that security forces could register and repent to guarantee their safety. Exemplary killings of around 100 security force members were conducted at Tikrit on June 11, 2014, and they were widely publicized. ISIL has also prosecuted a determined campaign of ethno-sectarian cleansing in areas that it controls, removing Shi`a Turkmen, Yazidis, Shabaks, Christians and even Sunni Muslim Kurds from its new territories. Most communities have been warned to leave, then targeted with progressive levels of violence including large-scale kidnap-murder sprees and car bombings that escalate over a two to three week period. ISIL is also purposefully blocking the flow of water and electricity to areas where minorities have been purged, apparently to deter resettlement of these areas.
ISIL’s Defensive Capabilities
For an organization that has benefited so greatly from exploiting mobility, the defense of fixed terrain presents a challenge. As J.M. Berger explained, “the calculus of holding territory has now changed. Prior to the pronouncement [of the caliphate], [ISIL] could have fallen back to its previous domain along the border of Iraq and Syria with little loss of face.” Now, as Jessica Lewis added in a separate article, “to validate its statecraft, [ISIL] must further demonstrate that its physical stronghold is defensible, or at least prevent rival militaries from attacking it.” As a prior CTC Sentinel piece argued, ISIL has “the tiger by the tail” now that its urban strongholds have to be defended. Yet in the face of weak initial counterattacks by the ISF, ISIL has shown itself to be fairly adept at defense, revealing some of the most interesting aspects of its recent military evolution into a hybrid army.
ISIL’s defensive playbook starts with the energetic consolidation of a defensive “crust” on the outer edges of newly-occupied areas in places where an ISF or Kurdish counterattack could be expected. ISIL has used its rough-and-ready field engineering skills to quickly create extensive earth berms and ditches mirroring the enemy’s own hastily-erected frontier defenses. After capturing Jalula on August 11, ISIL bulldozers immediately blocked key counterattack routes that the Kurds might use, emplacing numerous roadside bombs along these arteries. They further created a denied flank on the Diyala River by destroying the Jalula-Kalar road bridge, a common ISIL tactic to shape local geography to impede counterattacks or reinforcement by enemy forces. Flooding of lowlands is another known tactic for denying terrain to the ISF. Small numbers of well-sited heavy weapons are deployed, with anti-armor defense augmented with single hull-down T-55 or T-62 tanks, recoilless rifles, shoulder-fired anti-tank weapons, and, less frequently, guided anti-tank missiles. Extensive booby-trapping is undertaken in locations that are considered likely to be retaken by security forces.
ISIL’s engagement with local stakeholders and militants is perhaps the most critical aspect of its defensive arrangements. Following the defeat of al-Qa`ida in Iraq and the ISI by the Sahwa (Awakening forces), ISIL may recognize that local populations are as great a threat to its holdings as any external adversary. As noted previously, ISIL seeks to drive out any non-Sunni, non-Arab populations from its areas. This seems to be driven by ideological justifications and by more venal considerations (such as widespread looting of villages and ransoming of kidnap victims), but such purges also have the effect of creating depopulated zones. In many defensive environments, from the largely emptied Falluja city to new gains such as Suleiman Beg, ISIL may prefer to work in areas with few civilians, perhaps because of their accentuated fear of local uprisings and informers.
Where populations are present, ISIL is keen to overawe them and create a collaborative framework for the defense of such areas. As Iraq insurgency expert Aymenn al-Tamimi noted, ISIL raiders quickly raise their banners over key administrative and security headquarters and other landmarks to generate and disseminate images that compound the sense that they control areas. The movement issues basic instructions via billboards, leaflets and speakerphone or mosque speakers. In most places, ISIL does not issue—or at least does not police—the extensive Shari`a law city charters that it has introduced in its heartland cities, Raqqa and Mosul. Instead, its interactions are practical and focused on regime security: former ISF must register themselves and repent, commencing an evaluation process whereby such individuals may be recruited, taken as hostages or killed. ISIL usually already has some background in the area after years of studying and interacting with local communities, so its regime security measures are often well-informed.
As well as receiving individual pledges of allegiance, ISIL frequently absorbs whole networks of militants into its ranks in what might be termed as a mergers and acquisitions approach, with like-minded Salafist groups like Jamaat Ansar al-Islam being the simplest to convert. Existing Salafist groups, along with General Military Council forces associated with Jaysh Rijal al-Tariq al-Naqshabandi (JRTN) and other militants, contribute the core defensive manpower in ISIL-dominated areas. ISIL is adept at aligning with tribal needs, such as by plugging into the anti-Kurdish sentiments of Arab tribes around Jalula or allowing Arab tribes to harvest the ripe wheat fields of displaced Shi`a Turkmen farmers at Amerli. As Aymenn al-Tamimi explained, in time these allied groups become more and more closely aligned with ISIL, transitioning from “backing the winning horse” to deeper ideological radicalization, adding that “the longer they put off breaking with [ISIL], the more difficult it will become.” Where tribal groups have stood up to ISIL, they have prompted an extremely aggressive reaction, most notoriously at Zowiya (located at the junction of the Tigris and Lesser Zab rivers), where a tribal revolt was brutally put down with the aid of unusually sustained mortar fire and rampaging ISIL troops on July 7, 2014.
When ISF or Kurdish forces attack areas that ISIL has claimed, the movement has been quick to support the locals with specialized capabilities. Experienced ISIL anti-armor teams have achieved some spectacular results when tank-stalking. For instance, in Humayrah, near Ramadi, an Iraqi Army probe was decimated on April 20, 2014, with the loss of an entire mixed platoon of T-62 tanks and MTLB armored vehicles. In Tikrit, ISIL led a spectacular series of ambushes and suicide bombings against hasty and ill-conceived efforts by the Iraqi Army to take the town on July 16, 2014. At Jalula, ISIL has been fighting a gritty street-by-street battle against Kurdish special forces, armor and artillery, and ISIL led the powerful local counterattacks that restored all the lost neighborhoods to insurgent control on August 11, 2014. An August 8 effort to relieve the besieged town of Amerli was stopped dead by a single well-positioned ISIL-crewed T-55 tank, which shot up a convoy of 250 Shi`a militiamen mounted in utility vehicles.
ISIL’s Key Traits and Vulnerabilities
Although ISIL has undoubtedly done much to shape its own operational environment, it has nonetheless been lucky to face ill-prepared opponents in Iraq. The enfeebled state of the ISF has magnified ISIL’s reputation and confidence, temporarily masking its own weaknesses and vulnerabilities. ISIL is still riding a wave of military successes, but its opponents are recovering and drawing upon increasing international support. Its offensive power has tended to diminish as it approaches majority Shi`a or Kurdish-populated areas. Momentum has tremendous value in war, but it is fragile, and ISIL may be forced to gradually surrender the strategic initiative in Iraq, as it has done on individual Iraqi battlefields such as Kirkuk, which held against ISIL thrusts in mid-June, and Makhmour, which was retaken from ISIL on August 10. The group’s leadership is clearly comprised of talented deliberate planners, capable of crafting far-sighted political-military campaigns that are resilient enough to survive the deaths of their progenitors. Yet the pace of the war against ISIL is accelerating, and the group’s ability to continually shape and control the conflict will be sorely tested. Although they may boast a deep bench of talented individuals following years of prisoner releases, prison breaks and recruitment, leadership casualties will nonetheless complicate their ability to hold the initiative in the future.
Mobility and surprise have allowed ISIL to punch well above its weight in offensive operations, but these advantages may also be diminishing. If U.S. military support for Iraq increases, it will become more difficult for ISIL to achieve tactical surprise using vehicle-mounted raiding forces. Already the distinctive signature of such attacks has wrought disaster for ISIL attacks. In Tuz Khurmatu, for example, ISIL convoys sought to penetrate the city using night movements on August 9 and August 13, but were detected by the U.S. military, which provided Kurdish artillery with the coordinates required to blunt the attacks. Many islands of government or Kurdish control are being consolidated as launch-pads for future operations under the watchful gaze of U.S. intelligence, surveillance and reconnaissance (ISR) assets. ISIL will undoubtedly try to retain the initiative with strategic gambits, but attacking is becoming harder for the movement. This may cause it to fall back on older approaches such as the largely dismounted storming attacks and suicide vest operations used in Jalula on August 11 and in other “commuter insurgencies” such as Ramadi and Baghdad.
Defense may also become harder for the group as the ISF and Kurdish forces escalate their offensive operations. Drawing together the views of various experts, ISIL seems to have a Tigris valley-based offensive strike force (visible at Mosul, Tall Afar, and Tikrit) plus ancillary strike forces in the western Euphrates valley bordering Syria and another around Jalula and adjacent parts of the Hamrin mountain range. Yet these mobile elements are probably small, numbering less than 3,000 fighters, while the majority of ISIL’s defensive manpower, tied to specific areas, is made up of new recruits and allied movements. Although ISIL has momentum and these allies seem solidly behind the group, if the military tide begins to turn, particularly whilst the cement is still setting on ISIL’s relationships, there could be a dramatic reduction in the group’s effective strength. Already ISIL is being forced to relinquish multiple towns—Makhmour, Saadiyya, Muqdadiyah, Zummar, Bashiqa, Bartella, Qara Qosh—and the pace of operations is accelerating. If the ISF and Kurdish forces undertake selective offensive operations on a widening number of battlefields, the ISIL-led defense will undoubtedly become stretched, particularly if its ability to move and mass counterattacking forces is limited. ISIL could morph back into rural insurgents operating largely outside the cities once again.
Dr. Michael Knights is the Lafer Fellow at The Washington Institute for Near East Policy. He has worked in all of Iraq’s provinces, including periods embedded with the Iraqi security forces. Dr. Knights has been briefing U.S. officials on the resurgence of Al-Qa`ida in Iraq since 2012 and provided congressional testimony on the issue in December 2013. He has written on militancy in Iraq for the CTC Sentinel since 2008.
 In June 2014, ISIL declared a caliphate in Syria and Iraq and shortened its name to the “Islamic State.” ISIL was previously known as the Islamic State of Iraq, and prior to that al-Qa`ida in Iraq (AQI), which was led by Abu Mus`ab al-Zarqawi. In February 2014, al-Qa`ida chief Ayman al-Zawahiri disowned ISIL.
 Al-Qa`ida in Iraq amir Abu `Umar al-Baghdadi and war minister Abu Ayyub al-Masri were killed on April 18, 2010, the most senior of 34 top AQI leaders killed in the spring of 2010 (out of 42 top-tier leaders). See Michael Knights, “Back with a Vengeance: Al-Qaeda in Iraq Rebounds,” IHS Defense, Security & Risk Consulting, February 24, 2012.
 Deputy Assistant Secretary of State for Near Eastern Affairs Brett McGurk, testimony before the House Foreign Affairs Committee, July 23, 2014.
 Jessica Lewis, “The Islamic State: A Counter-Strategy for a Counter-State,” Institute for the Study of War, July 2014.
 Knights, “Back with a Vengeance,” pp. 2-3. Also see Murad Batal al-Shishani, “The Islamic State’s Strategic and Tactical Plan for Iraq,” Terrorism Monitor 12:16 (2014).
 Deputy Assistant Secretary of State for Near Eastern Affairs Brett McGurk, testimony before the House Foreign Affairs Committee, February 5, 2014.
 Jessica Lewis, “AQI’s ‘Soldier’s Harvest’ Campaign,” Institute for the Study of War, October 9, 2013, pp. 2-4.
 All insights in this paragraph are drawn from The Washington Institute’s Iraq violence dataset. In the most affected province, Kirkuk, quality attacks (involving advanced intelligence preparation, advanced tactics or use of special weapons or suicide devices) rose from 42 per month in July 2013 to 104 per month by May 2014.
 Lewis, “AQI’s ‘Soldier’s Harvest’ Campaign,” p. 8.
 McGurk, July 23, 2014.
 Ibid. McGurk’s statement provides details and a compelling narrative of the crumbling of ISF defenses in Mosul from June 8-10, 2014.
 Douglas A. Ollivant and Brian Fishman, “State of Jihad: The Reality of the Islamic State in Iraq and Syria,” War on the Rocks, May 21, 2014.
 Robert Scales and Douglas Ollivant noted that a key difference between ISIL and its predecessors in Iraq is that ISIL has “learned to build fighting units and teach weapons and tactics very well.” See Robert Scales and Douglas Ollivant, “Terrorist Armies Fight Smarter and Deadlier Than Ever,” Washington Post, August 1, 2014. Also see Kenneth Pollack, “Iraq: Understanding the ISIS Offensive Against the Kurds,” The Brookings Institution, August 11, 2014.
 See discussions of new ISIL training camps in Iraq in McGurk, July 23, 2014. Also see discussion of the dangers faced by unarmored Iraqi helicopter sorties over “ISIL camps defended by PKC machine guns and anti-aircraft platforms” in McGurk, February 5, 2014.
 McGurk, July 23, 2014. Ahmed Ali, Jessica Lewis, and Kimberly Kagan put the number at 150 vehicles with 500-800 personnel in “The ISIS Battle Plan,” Institute for the Study of War, June 12, 2014.
 Alex Bilger, “ISIS Annual Reports Reveal a Metrics-Driven Military Command,” Institute for the Study of War, May 22, 2014. The report, based on ISIL’s claims, suggests that ISIL carried out an average of 640 attacks per month in 2013, representing the majority of violence in the country. (Counting only the types of attacks that ISIL records, ISIL’s claims equate to around 64% of The Washington Institute’s Iraq violence dataset in the same period. This seems like an accurate reflection of ISIL’s balance of effort within Iraq’s insurgency.)
 The author held conversations with Aymenn al-Tamimi and Aaron Zelin, two scholars on ISIL, and factored in the views of Dr. Hisham al-Hashimi, who has had access to ISIL data captured from the safe house of Abu Abdul Rahman al-Bilawi, al-Baghdadi’s military chief of staff for Iraq. See Ruth Sherlock, “Inside the Leadership of Islamic State: How the New ‘Caliphate’ is Run,” Daily Telegraph, July 9, 2014.
 Personal interview, Aaron Zelin, August 16, 2014.
 Jessica Lewis presciently noted that the ISI emerged from the campaign as “a military organization typified by its operational planning, as opposed to a disrupted and leader-centric terrorist organization.” See Jessica Lewis, “Al-Qaeda in Iraq Resurgent, Part II,” Institute for the Study of War, October 9, 2013.
 This is a U.S. military term. See Curtis E. LeMay, Center for Doctrine Development and Education, Volume I, Basic Doctrine, October 14, 2011, pp. 59-60.
 ISIL’s wilayats in Iraq currently include: Wilayat Ninawa; Wilayat Anbar; Wilayat Kirkuk; Wilayat Salah ad-Din; Wilayat Diyala; Wilayat Shamal Baghdad (north Baghdad); and the Wilayat Janub (south Baghdad and Jurf al-Sakhr). The author would like to thank Aymenn al-Tamimi for his generous assistance in supporting this article.
 Accounting for such variations is the aim of Lewis, “Al-Qaeda in Iraq Resurgent, Part II.” The messy character of some multi-city mass casualty waves is very familiar to the author from his own experiences monitoring the daily significant actions in Iraq from within a private security company. Some cells were largely independent, particularly in Anbar, while others consistently undertook attacks early or late.
 A good example of ISIL’s use of tactical surprise is the attack on Samarra on June 5, 2014. See Kareem Fahim, “In Brazen Strike, Sunni Militants Storm Central Iraqi City,” New York Times, June 5, 2014. Kurdish forces suffered debilitating tactical surprise at numerous points between August 1-11. See Pollack.
 One recent Tuz Khurmatu night attack is mentioned in ISW Iraq Team, Lauren Squires, and Nichole Dicharry, “Iraq Situation Report: August 13, 2014,” Institute for the Study of War, August 21, 2014.
 A point made by Pollack.
 Most ISIL columns seem to comprise 10-30 vehicles, almost all of which are reliable soft-skinned utility vehicles, some carrying heavy machine-guns or anti-aircraft cannons. Tanks and tracked personnel carriers remain rarer, in part due to their lack of long-distance mobility. See personal interview, Alexandre Massimo, August 12, 2014.
 In retrospect, the opening shot of the June offensive, the Samarra attack, may have been a strategic feint to distract Iraqi government attention and resources, which it did. See Fahim.
 Personal interview, Kurdistan region security official, August 14, 2014.
 Personal interview, Alexandre Massimo, August 12, 2014.
 This is a phrase from the dawn of tank warfare in World War I to denote the dissolving effect on troop morale when soldiers face an armored vehicle that they believe they cannot damage. See David Stevenson, With Our Backs to the Wall: Victory and Defeat in 1918 (London: Penguin, 2011), p. 222.
 These included at least one M117 Guardian armored security vehicle, one Dzik-3 infantry mobility vehicle, and one MT-LB tracked personnel carrier. See personal interview, Alexandre Massimo, August 12, 2014.
 Personal interview, Kurdistan region security official, August 14, 2014.
 Mohammed al-Dulaimy and Hannah Allam, “Witnesses Describe How Islamists Leveled Sunni Village as a Warning,” McClatchy Newspapers, July 11, 2014.
 ISIL has significant numbers of suicide operators and car bombs to utilize in such attacks. Due largely to the influx of foreign fighters attracted by the Syrian jihad, suicide operations have risen from an average of six per month in Iraq in 2010 to an average of 43 in 2013. Car bombings rose from 10 per month in 2010 to 71 per month in 2013. See Michael Knights, “The Resurgence of Al-Qaeda in Iraq,” testimony before the House Foreign Affairs Committee, December 12, 2013. For the full testimony, see www.washingtoninstitute.org/uploads/Documents/testimony/KnightsTestimony20131212.pdf.
 Government reinforcements were targeted with a series of roadside bombs. The attack, in which 23 security personnel were killed, generated widespread publicity. See Knights, “Back with a Vengeance,” p. 3.
 Personal interview, Alexandre Massimo, August 12, 2014.
 Scales and Ollivant, “Terrorist Armies Fight Smarter and Deadlier Than Ever.”
 McGurk stated: “The fall of Iraq’s second largest city to ISIL was combined with a social media campaign indicating that ISIL columns would soon be heading down the Tigris River Valley to Baghdad with no mercy for anyone who resisted.” See McGurk, July 23, 2014.
 Sarah Leah Whitson, “Iraq: ISIS Abducting, Killing, Expelling Minorities: Armed Group Targeting Christian Nuns, Turkmen, Shabaks, Yazidis,” Human Rights Watch, July 19, 2014. Massacre videos were also re-released at the close of the Soldier’s Harvest campaign on July 30, 2014. See Damien McElroy, “Islamic State Jihadists Issue 30-Minute Killing Spree on Video,” Daily Telegraph, July 30, 2014.
 To give examples from the Shi`a Shabak community east of Mosul, ISIL started its campaign with a double suicide car bombing in the Shabak town of Khuzna Tappah area on June 6, the opening day of the Mosul uprising, followed by another suicide car bombing in Khuzna Tappah on June 26. In Bazwayah, a Shabak town of 3,500 residents, 105 people were abducted between June 10 and July 18. An ISIL force of 60 vehicles entered the Shabak town of Umarkan on July 2, burned down the local Shi`a shrine and a partially constructed mosque, and also confiscated cars, weapons and more than 100 head of cattle. All 250 Shi`a Shabak families in the village fled immediately. All material garnered from open source news reporting. A good collation of new reporting and first-hand views can be found in Whitson.
 ISIL has cut off the water supplies to numerous minority villages in the Ninawa Plains by controlling the Salamiyya and Rashidiyya pumping stations on the Tigris River, and has done so in the siege of Amerli also. ISIL also prevents gridded power from reaching minority villages. See Whitson. Also see Michael Knights, “Iraq’s City of Orphans,” Foreign Policy, August 14, 2014.
 J.M. Berger, “Gambling on the Caliphate,” Intelwire blog, June 29, 2014.
 Lewis, “The Islamic State: A Counter-Strategy for a Counter-State,” p. 11.
 Michael Knights, “The ISIL’s Stand in the Ramadi-Falluja Corridor,” CTC Sentinel 7:5 (2014).
 Isabel Coles, “Purge of Minorities Re-draws Iraq Map,” Reuters, July 24, 2014.
 “Peshmarga Mobilize to Restore Jalawla and ‘ISIS’ Detained a Local Official,” Shafaaq News, August 12, 2014. The United States used airpower to destroy a number of “IED emplacement belts” around Mosul Dam on August 16-18, 2014. See one of these operations referenced at “U.S. Military Conducts Airstrikes Against ISIL near the Mosul Dam,” U.S. Central Command, August 18, 2014.
 In general, bridge demolition has been a widespread part of ISIL’s tactical repertoire. See
“ISIL Destroys 63 Bridges in Iraq This Year,” al-Shorfa, August 7, 2014.
 For commentary on Falluja’s regulating dam, see Knights, “The ISIL’s Stand in the Ramadi-Falluja Corridor.”
 For a sample of the kind of light anti-tank weapons reaching Iraq, see “ISIS Deploys Croatian Weapons Against The Iraqi Army,” Brown Moses Blog, March 8, 2014. The entry shows RBG-6 grenade launchers, M60 and SPG-9 recoilless rifles, as well as RPG-22 rocket and M79 Osa launchers. For information on guided missiles, see Charles Lister’s August 9, 2014, tweet, “ISIS ATGM use is increasing in #Iraq.”
 ISIL uses unmanned car bombs, bicycle bombs and explosives-rigged houses. See Ruth Sherlock and Carol Malouf, “Islamic State Booby Traps Massive Iraqi Dam Which Could Kill Thousands if Breached, Daily Telegraph, August 18, 2014.
 Personal interview, Yazidi civilian, August 12, 2014. Also see Whitson. There are widespread scattered references in most ISIL ethnic cleansing stories to ways that ISIL members make money at the sidelines of militant operations, through kidnap, looting, cattle rustling and bribery. As such, fighters appear to be poorly paid—just $41 per month compared to $150 for a laborer, according to RAND’s Patrick B. Johnston—they have significant incentive to moonlight in this manner. See Johnston quoted in Al-Dulaimy and Allam.
 Although there are numerous rumors of human shields being present at ISIL locations, these persons, if they exist, do not seem to deter Iraqi fliers from undertaking strikes. That could change if U.S. airstrikes continue to intensify and human shields become more useful. For an example, see “ISIS Prevents Saadia Residents from Leaving and Uses Them as Human Shields Against Air Strikes,” Shafaaq News, August 7, 2014.
 “Update On Iraq’s Insurgency: Interview With Aymenn Jawad al-Tamimi,” Musings on Iraq blog, July 1, 2014.
 Personal interview, Kurdistan journalist, August 17, 2014.
 Personal interview, Aymenn al-Tamimi, August 12, 2014.
 In Falluja, the author has a full seven months of case study material showing how ISIL starts gently, but steadily degrades rival groups with which it has partnered, in this case Hamas al-Iraq. See Knights, “The ISIL’s Stand in the Ramadi-Falluja Corridor.”
 Personal interview, Kurdish official from Tuz district, August 15, 2014.
 Personal interview, Aymenn al-Tamimi, August 12, 2014.
 Al-Dulaimy and Allam.
 Knights, “The ISIL’s Stand in the Ramadi-Falluja Corridor.”
 Alissa Rubin and Suadad al-Salhy, “For Iraq, Debacle in Tikrit as Forces Walk Into Trap Set by Militants,” New York Times, July 16, 2014.
 “20 Peshmerga Killed and Wounded in Suicide Attack in Jalawla, Diyala Province,” NINA Agency, August 11, 2014.
 Knights, “Iraq’s City of Orphans.”
 Isabel Coles, “On Edge of Kirkuk, Peshmerga Prepare to Fight Again for Kurdistan,” Reuters, June 19, 2014. The Kurds fought hard near Mullah Abdulla power station to prevent an ISIL exploitation toward Kirkuk city.
 “Iraqi Kurds Retake 2 Towns from Militants, Helped by U.S. Airstrikes,” CBS News, August 10, 2014. Large numbers of other articles cite examples from Zummar, Mosul Dam, and the Ninawa Plains. For a selection, see Jessica Lewis, Lauren Squires, and Nichole Dicharry’s reporting from August 13-17, 2014, at www.iswiraq.blogspot.com.
 For commentary on the May 2014 death of Abdul Rahman al-Bilawi, al-Baghdadi’s military chief of staff for Iraq, see Sherlock. ISIL’s senior military commander, Haji Bakr, was likewise killed in northern Syria in early January 2014. See Bill Roggio, “ISIS Confirms Death of Senior Leader in Syria,” The Long War Journal, February 5, 2014.
 Personal interview, Kurdish official from Tuz district, August 15, 2014.
 These include the Bayji oil refinery and numerous facilities at Haditha; the Iraqi base at Tikrit air base (the old Forward Operating Base Speicher); areas of Sinjar and Mosul; and key government and air transportation sites in Baghdad.
 The “commuter insurgency” refers to an urban fight in which insurgents travel in each day, like suburban commuters, from support zones on the outskirts. Coined by U.S. forces in Iraq, the concept is explained further in David Kilcullen, The Accidental Guerrilla: Fighting Small Wars in the Midst of a Big One (Oxford: Oxford University Press, 2009), p. 142.
 See aforementioned conversations with Aymenn al-Tamimi and Aaron Zelin, plus the views of Dr. Hisham al-Hashimi, via Sherlock.
 For a selection, see Jessica Lewis, Lauren Squires, and Nichole Dicharry’s reporting from August 13-17, 2014 at www.iswiraq.blogspot.com.