The Military Campaign Against the Islamic State: An Assessment

On September 9, Michael Knights, James Jeffrey, Michael Eisenstadt, and Andrew Tabler addressed a Policy Forum at The Washington Institute. Knights is a Boston-based Lafer Fellow with the Institute and author of The Long Haul: Rebooting U.S. Security Cooperation in Iraq. Jeffrey is the Institute's Philip Solondz Distinguished Fellow and former U.S. ambassador to Iraq and Turkey. Eisenstadt is the Institute's Kahn Fellow, director of its Military and Security Studies Program, and author of "An Enhanced Train-and-Equip Program for the Moderate Syrian Opposition" (with Jeffrey White). Tabler is the Martin J. Gross Fellow in the Institute's Program on Arab Politics. The following is a rapporteur's summary of their remarks.

MICHAEL KNIGHTS

The landscape in Iraq has changed markedly since September 2014, offering a few major lessons in the nature of local warfare. Two years ago, the Islamic State (IS) had achieved a firm base of control in Mosul, Iraq's second-largest city. Yet its offensives in the Kurdistan Regional Government prompted the United States and others to step up their involvement. At the time, some Iraqis believed that Washington had hesitated too long after the fall of Mosul, in contrast with other actors who had intensified their efforts against IS during the same period, such as Iran, Russia, and the Shiite Popular Mobilization Units (PMUs).

Today, IS military and defensive capabilities in Iraq have been degraded, and the group's loss of key territory has interfered with its ability to recruit, instill fear, and capitalize on oil holdings. These achievements were largely made possible by the partnership between the Iraqi security forces and the Combined Joint Task Force, the truly global coalition tasked with carrying out Operation Inherent Resolve (OIR). This partnership proved overwhelmingly successful in liberating key Iraqi cities, though the question remains how Iraqis will remember the conflict's decisive factors.

Whatever the case, the military campaign has offered three lessons thus far. First is the importance of leadership in war. It was not the failures of average Iraqi and Kurdish forces that enabled IS to expand in 2011-2014, but rather the failure of leadership to act decisively in the face of repeated warnings that the group would soon launch major offensives.

Second, the campaign has reiterated the importance of small, hard forces in prosecuting an enemy despite manpower shortages. Although the Islamic State's ability to achieve superior mobility and concentrate its forces on the frontlines contributed to its success early on, its enemies have since managed to stretch the group beyond its capabilities.

Third, time and attrition have served as a powerful weapon for all sides in the war. Yet events have also demonstrated that this weapon often backfires. 

The next stages of this war will involve fighting in Iraq's ungoverned spaces. To combat future IS insurgencies emanating from such spaces, the United States should double down on cooperation with Iraq's security forces, arming and training them in counterterrorism, border security, intelligence techniques, and targeting, among other things. Washington should also work through the G-20 coalition to promote reform and cooperation among Iraqi forces and Kurdish Peshmerga units, as well as local governance projects in Sunni and Shiite areas.

JAMES JEFFREY

Despite OIR's perceived successes, IS remains a potent force in Iraq and Syria, retaining control over its strongholds in Raqqa and Mosul and continuing to function as a state. It persists despite a sixty-country coalition aligning against it, including a large number of aircraft and Iraqi, Peshmerga, and PMU forces on the ground.

Given this backdrop, why hasn't IS been defeated? The answer lies in the political challenges and calculations confronting each player.

For Baghdad, stabilization of the frontlines removed the Islamic State's destruction as priority one, despite the fear generated by the group's initial victories. Furthermore, the fight against IS has been overshadowed by other security challenges, including Iranian expansionism-by-proxy, the spread of regional sectarian conflict, and growing violence between Iraq's Sunni tribes.

The calculus is different for the Kurdish Peshmerga, who have proved themselves Washington's most reliable ally against IS. Despite the challenge of mobilizing large forces across a long front and dealing with numerous refugees, the Kurds have the hard capabilities and the political and economic motivation (read: control over oil) to sustain the fight.

For its part, the United States was slow to move even after the fall of Mosul in June 2014, and did not commence the bombing campaign against IS until that August. The caveats and inertia that hamstring the Obama administration's Iraq policy are unrelated to the nature of the threat, but stem directly from a principled reluctance to use military force in that country. Accordingly, the real challenge lies not in the prospect of getting post-IS reconstruction wrong, but rather in the possibility that fear of failure will prevent decisive action altogether.

Iran, meanwhile, sees every issue in the region through the same lens: that of expanding its reach and improving its long-term standing. Accordingly, it has sought to expand into Iraq in recent years via relationships with Shiite groups and Kurds, and it will continue to do so. Yet Tehran does not want to get bogged down in a war against IS, so it is unlikely to fully commit to the group's destruction.

The longer the war drags on, the longer its costs will accumulate. Many Iraqi civilians will continue to face the prospect of life under IS, combatants will continue to die, and the international community will continue to face terrorist attacks and their political reverberations. From that perspective, whatever comes next in Mosul and Raqqa will be preferable to IS control. The question is how fast and at what cost the next U.S. administration will seek the group's destruction.

MICHAEL EISENSTADT

In Syria, OIR has consisted of an air campaign to destroy IS ground assets (including oil-related infrastructure), provide close air support for allies, and target IS commanders. U.S. Special Forces have also conducted raids and advised and assisted the People's Defense Units (YPG), among other allies. Successes include taking back 20 percent of IS territory, diminishing the group's oil income, and perhaps reducing the number of foreign fighters traveling to Iraq and Syria. A major sign of the damage done to IS lies in the fact that it has not conducted major offensive military operations since its capture of Ramadi (in Iraq) and Palmyra (in Syria) in May 2015.

Yet the question remains: how will IS eventually be defeated? The Pentagon says it plans to "envelop and collapse" the group in Raqqa and Mosul, but this may not necessarily translate into defeat: in Afghanistan in 2001 and Iraq in 2003, the collapse of enemy resistance led to their return as insurgents. This outcome is especially likely given the persistent power vacuum in much of the country.

One must also consider how the effort to train and equip the Syrian opposition has influenced OIR. The United States began covertly arming so-called "moderate" rebels in 2013, both to pressure Bashar al-Assad's regime and to rein in Arab and Turkish allies who were arming more extreme rebel groups. This effort was consistently underresourced, however, spurring many fighters to gravitate to better-funded extremist groups such as al-Qaeda affiliate Jabhat al-Nusra and IS. Washington's pursuit of a nuclear deal with Iran exacerbated this trend by convincing some rebels that America was tacitly aligned with Tehran and its Damascus client. Meanwhile, Washington's more overt 2014 program to train and equip anti-IS forces failed, further complicating efforts to achieve OIR's goals.

In general, too much of U.S. policy in Syria has focused on national-level solutions. Syria will remain a broken state for the foreseeable future, so Washington should abandon its tendency toward "solutionism" and focus instead on managing the conflict by seeking local, bottom-up arrangements. By the same token, it must remain engaged in Syria; although terrorism is not an existential threat, it does have the potential to alter the domestic political landscape in Europe (to Russia's benefit) and the United States. Finally, Washington should take steps to ensure that the collapse of IS in Raqqa and Mosul does not simply push the group's fighters into neighboring states and further destabilize them.

ANDREW TABLER

The diplomatic aspects of the Syria war, especially the lack of a real political solution, make it more difficult to prosecute the campaign against IS. Last year's negotiations by the International Syria Support Group laid the basis for the cessation of hostilities adopted this February, yet while the agreement initially reduced violence, Assad's stubbornness quickly compromised its sustainability. Meanwhile, attacks by regime and opposition forces spoiled the negotiations and prompted Assad to reignite the war around Aleppo.

This strategy of squeezing the opposition to elicit concessions exposed a key vulnerability: while the regime remained fully engaged in Aleppo, manpower shortages compromised its efforts against IS elsewhere. More generally, the regime has prioritized fighting other elements of the opposition, leaving its fight against IS underresourced. Another consequence of manpower shortages is that progress against Sunni extremists has come with a tradeoff: the expansion of Hezbollah and other Shiite militias in Syria.

As the cessation of hostilities deteriorated, another potential deal arose whereby the regime would cease targeting the opposition in exchange for U.S. military cooperation with Russia against IS and other extremist groups. Current signs indicate that Washington seeks to lay the groundwork for a more comprehensive political solution to the war. Major factors affecting such a settlement include the regime's use of chemical weapons; the relationship between Turkey, the Democratic Union Party (PYD) in Syria, and the Kurdistan Workers Party; and the ability of different groups to take and hold parts of the Euphrates River Valley, including Raqqa.

More broadly, one can draw several lessons from the conflict thus far. First, the regime's stubbornness means that the underlying political factors are unlikely to change, and the broken-state problem will likely stick around for years to come. Second, manpower shortages will constrain both the waging of the civil war and the campaign against IS; as a result, neighboring states will continue to extend their spheres of influence within a divided Syria. Finally, defeating IS militarily may simply spread the group out, bringing the threat of terrorism closer to the West and even the U.S. homeland.

This summary was prepared by Kendall Bianchi.