Ideas. Action. Impact. The Washington Institute for Near East Policy The Washington Institute: Improving the Quality of U.S. Middle East Policy

Other Pages

Policy Analysis

PolicyWatch 2778

Defeating the Islamic State in Iraq, By the Numbers

Michael Knights

Also available in العربية

March 29, 2017

Iraq and the Kurdistan Region are America's strongest allies in the war against IS, and sustained U.S. security assistance will be vital to finishing the job.

Last week saw Iraqi security forces (ISF) entering the northwestern quadrant of Mosul, the last quarter of the city still under Islamic State control. The advance coincided with a Washington summit of coalition officials from sixty-eight nations to discuss the next stages of the war against IS. As attention turns toward pursuing the group beyond Mosul, it is worthwhile to recount how IS forces have been beaten on the battlefields of Iraq so far, and what lessons should be drawn from this experience to guide future U.S. and international support to the Iraqi and Kurdish armed forces.


The war has been marked by intense and counterproductive competitiveness between supporters of the main fighting forces in Iraq. The largest of these are the central government's ISF, which comprise the Counter-Terrorism Service, the army, and the Federal Police. Next up are the Kurdish forces: the Kurdistan Regional Government's Peshmerga military units and their militarized police counterparts, the Zerevani, run by the KRG Interior Ministry. Third are the Popular Mobilization Units (PMUs), the Shiite volunteer militias raised by Grand Ayatollah Ali al-Sistani's June 2014 fatwa; these include some Iranian-backed Shiites who had fought the coalition and Iraqi government in prior years.

It is important to recount the combined contributions these forces have made before the passage of time distorts the facts. First, a clearer picture of the war's burden sharing would help the Trump administration appreciate the manner in which Iraqis and Kurds largely liberated themselves in this conflict, doing the vast majority of the actual fighting on the ground (with powerful and indispensable assistance from the coalition, of course). Second, U.S. officials should correct the pervasive misunderstanding that the Kurds have carried a disproportionate burden in the fighting -- a perception exacerbated by the relative ease of reporting from KRG territory during the war. In fact, every available metric shows that the ISF fought more battles and liberated more cities than other forces. This reality matters as the United States and other coalition nations design their future security cooperation with Iraq and the KRG. Even taking into account the heroic Kurdish and PMU contributions, the ISF have carried the greatest burden so far and will face the greatest future challenges in terms of preventing the Islamic State's return.


A review of operations in the non-Kurdish parts of Iraq highlights the paramount effort (eventually) undertaken by the ISF. Following the plainly disastrous collapse of six army and Federal Police divisions in June 2014, PMUs played a valiant role in holding a "line of no retreat" in Samarra, Diyala, and the outskirts of Baghdad. Sunni tribes partnered with the ISF played a similarly heroic but underreported role in holding Ramadi and Haditha at a time when IS was running rampant over a third of the country.

Later that year, PMUs led the first counteroffensives at Amerli and Jurf al-Sakhar, but by the time the battles for Tikrit, Ramadi, Bayji, Fallujah, and Hit came around in 2015-2016, the coalition-backed ISF had taken over as the main counteroffensive forces. Similarly, the approach battles outside Mosul -- at Makhmur, Qayyara, and al-Sharqat -- and the ongoing campaign for the city itself have been led and fought largely by the ISF. Iraqi citizens have come from all over the country to liberate Sunni Mosul, including tens of thousands of Shiites from the south.

The Kurds have a similarly proud record in the war. After suffering military collapses in August 2014 when IS turned its sights on the KRG, they recovered quickly and mounted immediate counteroffensives. The war they fought was very different from that faced by the ISF; it consisted of numerous defensive actions and short-range counterattacks to retake their original positions. The Kurds had the advantage of fighting from a secure base and a firm, contiguous frontline, which the ISF and PMUs lacked due to the hodgepodge of IS-controlled areas elsewhere in Iraq.

Over the past two years, Kurdish forces have regained territory around Jalula, Qara Tapa, Tuz Khormatu, and the oil hub of Kirkuk. They also undertook a major long-range offensive to win back the Zummar area, Mosul Dam, Rabiyah, Sinjar, and Kisik. More recently, they have provided vital intelligence and logistical support during the battle for Mosul, in addition to directly joining the tough break-in battles for the first four miles of the eastern quarter's thirteen-mile outer defenses.


The metrics of the war against IS give a sense of what has been achieved so far and what remains to be done. The Kurds held a fortified 500-mile frontline with IS for nearly three years, while the ISF maintained a sprawling and porous frontline that meandered for over 1,250 miles. The ISF have reclaimed 36,000 square miles from the group, and the Kurds a further 3,140. Tal Afar, Hawija, al-Baaj, and the western Euphrates River Valley will need to be liberated next, mainly by ISF and PMU forces with occasional Kurdish assistance. The remaining IS-held or unsecured areas of Iraq comprise some 14,700 square miles of mostly desert terrain, presenting a huge challenge to the ISF.

In addition, the Syria border needs to be secured, including the 277-mile stretch under nominal ISF control and the 87-mile portion under nominal Kurdish control. The KRG's internal frontiers need to be secured against infiltration as well, but at the same time opened partially to allow normal trade with the rest of Iraq. This will require two-way intelligence sharing between Baghdad and Erbil, plus improved counterterrorism screening capabilities.

In short, much is still to be done, and the next stages of the war will require the ISF and Kurdish forces to develop new capabilities. Huge areas will need to be secured, many of them very remote, placing emphasis on wide-area surveillance technologies, helicopter-based rapid reaction forces, and logistical sustainment at faraway operating locations. Borders and internal checkpoints must be buttressed against the inevitable IS mass-casualty terrorism campaign that will follow the group's battlefield defeat. Intelligence and counter-organized crime capabilities also need to be improved to prevent IS from regenerating as an ultraviolent mafia, as it did in Mosul prior to 2014. There is a big job still to be done by the ISF, and a major supporting role for the Kurdish security forces.


The United States should recognize that Iraq and the KRG have been its greatest allies in the war against IS, and the Iraqis should accept that the American-led coalition effort has made their battlefield victories quicker and less destructive. Going forward, the Combined Joint Task Force-Operation Inherent Resolve mechanism should be maintained, as opposed to creating a new arrangement or seeking a formal Status of Forces Agreement (the latter option in particular could undermine Prime Minister Haider al-Abadi by forcing him to gamble his political career on a contested parliamentary treaty ratification that would likely fail). At minimum, Washington needs to commit to enhanced intelligence sharing and sustained security assistance to the Counter-Terrorism Service, army, and Federal Police for three to five years in order to build the new capabilities described above and let improvements take root.

Meanwhile, the coalition should encourage the ISF and KRG to continue the military cooperation that has made many of the victories over IS possible, including in the ongoing Mosul campaign. If defeating the Islamic State is Washington's "number-one goal in the region," as Secretary of State Rex Tillerson stated last week, then an ongoing, enhanced security cooperation program with Iraq and the Kurdistan region must be put in place to bolster America's most battle-hardened allies in this war.

Michael Knights is a Lafer Fellow with The Washington Institute and author of its report "How to Secure Mosul." He has worked in all of Iraq's provinces and spent time embedded with the country's security forces.