What will it take on the ground to defeat the Islamic State of Iraq and the Levant (ISIL)? What is the nature of America’s current conflict against ISIL? Can the Iraqi Security Forces (ISF), bolstered by U.S. air power, advisers, special forces—almost everything short of ground combat forces—defeat ISIL? These are important questions that have come to the fore with news of the stalled Iraqi offensive against Tikrit, the fumbled announcement out of U.S. Central Command of the now postponed (if it ever was scheduled) ISF offensive to retake Mosul, and the debate over President Barack Obama’s request to Congress for an Authorization for the Use of Military Force (AUMF) to fight ISIL. The more important question is this: Can the United States realize its stated policy objective of defeating ISIL without U.S. ground combat forces? The answer is no.
Many have already commented on the need to have all U.S. options available to defeat ISIL. Retired Marine Corps General Jim Mattis recently wrote that this should include ground combat forces “to achieve our war aims.” What has been missing from the debate is an assessment of why U.S. ground forces are not just “better” than the ISF, but absolutely necessary for achieving U.S. policy objectives against ISIL. Pulling out one’s copy of Clausewitz’s On War is a good place to start.
President Obama, in his February 15 letter to the Congress requesting an AUMF, clearly reiterated his desired end state: the degradation and defeat of ISIL. To this point in the fight against ISIL, the U.S. “way” has been limited to “a systematic campaign of airstrikes against ISIL in Iraq and Syria” and supporting various anti-ISIL security forces. American “means” are limited to air power, advisers, and U.S. support to the Iraqis. The other means beyond U.S. supporting forces—the “boots on the ground”—include the ISF, Kurdish Peshmerga and Sunni and Shi’a militias, the latter backed by the Iranian Revolutionary Guard Corps. Indeed, Major General Qasem Soleimaini, former leader of the Iranian Quds Force, is directing the offensive to retake Tikrit.
Reaction in Congress and among commentators to the request for the AUMF has been predictably divided and largely centered on the question of the introduction of U.S. ground forces. Although the administration continues to emphasize that all options are on the table, the letter from the president specifically states that it would “not authorize long-term, large-scale ground combat operations like those our nation conducted in Iraq and Afghanistan.”
This is the fundamental flaw in conceptualizing a strategy for defeating ISIL in Iraq—seeing this new fight as an extension of the past 14 years of war in Afghanistan and Iraq. Again, Clausewitz is instructive when he stresses that war is “an instrument of policy…This way of looking at it will show us how wars must vary with the nature of their motives and of the situations which give rise to them.” In other words, the United States needs to understand the war it is in and the adversary it faces.
ISIL is more than an insurgency attempting to challenge the legitimacy of the Iraqi government; it is a protostate bent on a war of conquest. Thus, the centrality of “protecting the people” from the insurgents that is the cornerstone of U.S. counterinsurgency doctrine—the way the United States eventually approached the wars in Afghanistan and Iraq—is irrelevant to ISIL itself. Protecting the Iraqi population from ISIL is important, but that will be accomplished through conventional operations whose objective is ISIL’s destruction.
Current U.S. and coalition efforts have halted the advance of ISIL and degraded its capabilities. This has been accomplished through air power and limited Iraqi ground operations. In response, ISIL has gone to ground in urban areas. This creates a new reality on the ground and a problem that cannot be solved through airstrikes alone. ISIL fighters are now able to conceal themselves in the terrain and amongst the people of the cities they occupy. They are more akin to Hamas in Gaza or the North Vietnamese Army in Hue, decades ago, than they are to any insurgency. These urban areas are where ISIL will have to be defeated if the United States is to realize its policy objective.
U.S. success is therefore inextricably linked to ground combat operations against ISIL in perhaps the most difficult tactical environment of a densely populated urban battlefield. Again, the U.S. approach to date has been to train and enable the ISF and, perhaps, embed advisers and tactical air controllers with them to increase their effectiveness. This is the Achilles heel of U.S. military strategy: the central assumption that the ISF will provide sufficient military “means” to achieve U.S. strategic “ends.” The question that has yet to be asked and answered without spin is fundamental to our policy: What if the ISF cannot be trained and advised to a level of competency necessary to roll back ISIL?
Operations in Tikrit provide some indication of the competence of the ISF. Nevertheless, the key test will be the retaking of Mosul, a Sunni city of some 1.5 million residents. Doubts about the readiness of the ISF for this fight ostensibly pushed back plans for an offensive to take Mosul from this spring to an undetermined date in the future.
There is reason for concern. The ISF that fled in the face of ISIL bolted because it was designed largely as an internal security force. The ISF could only operate effectively with significant U.S. assistance against anything other than moderate-scale internal threats. It is incapable of the combined arms maneuver required to defeat ISIL. The tough urban fights in Iraq—Fallujah (2004) and Sadr City (2008)—were dominated by U.S. forces with modest ISF participation. The battle for Basra (2008), while Iraqi conceived and led, required massive U.S. assistance to succeed. The U.S. ground formations in these key battles were not just “boots on the ground.” They were skilled, professional forces capable of something the ISF is not: the expert execution of highly synchronized joint combined arms operations. This competence is paramount in defeating determined adversaries and avoiding friendly and noncombatant casualties and collateral damage. General Mattis’s characterization of U.S. ground forces is correct: “the fiercest, most skillful and ethical combat force in the world.” This is the ground force that is needed to defeat ISIL. U.S. advisers cannot transplant these competencies into the ISF in a relatively short time, if ever, even if the ISF did not have all of its other challenges to effectiveness to overcome.
The 2008 Battle of Sadr City is perhaps the most illustrative example of the chasm between U.S. ground forces and the ISF—or almost any other military in the world, for that matter. In that battle the U.S. Army’s 3rd Brigade Combat Team, 4th Infantry Division, destroyed the Jaysh al-Mahdi (JAM) militia in an intense ground fight. Sadr City contained over 2 million Iraqi noncombatants, with an estimated 6,000-8,000 JAM fighters operating amongst them. The problem was similar to that which forces trying to retake Mosul will face: How to defeat a relatively small number of fighters without wantonly killing the civilians amongst whom they are hiding and destroying the city. To reverse a famous quote reported by Peter Arnett during the Vietnam War, “How do you save the city without destroying it?”
The U.S. in the Battle of Sadr City created a condition that was intolerable to JAM when it began sealing off the city with a concrete wall and using the protected mobility and firepower of M1 Abrams tanks and Bradley infantry fighting vehicles to maneuver against JAM. This threatened JAM’s source of sustenance and they came out to fight U.S. forces to stop the progress of the wall. When JAM fighters became visible they were destroyed with discriminate firepower. This is not unlike Israeli ground operations in Gaza during Operations Cast Lead and Protective Edge—competent ground forces, enabled by a joint system, creating conditions that force an adversary to fight at great disadvantage.
Simultaneous with the ground fight against the JAM militia, the 3rd Brigade executed a high-technology, complex hunt for JAM rocket launcher crews who were firing from Sadr City into the Baghdad Green Zone, where the U.S. Embassy was located. The brigade staff, augmented by Air Force officers, integrated multiple intelligence means, unmanned aerial surveillance and attack systems (Predator and Shadow), Apache helicopters, Air Force fighters, and artillery to hunt and destroy JAM rocket launchers. The ISF was also in the Sadr City fight, but it played a secondary infantry role, enabled by U.S. advisers, focused on consolidating gains and occupying Sadr City once the fighting ended. It did not execute combined arms operations. While isolating Mosul might not be the best strategy, the fight for Sadr City illustrates the unique effectiveness U.S. ground forces could have in the fight against ISIL.
Competent ground forces are a fundamental part of the joint force equation that constitutes the U.S. military system to find and defeat adversaries. Attempting to impart this competence to another ground force is folly. The ISF of 2008, before then Iraqi Prime Minister Nouri al-Maliki riddled it with crony appointments and corruption, was more competent than the ISF that fled ISIL. Still, it is unimaginable that the ISF of 2008 could have done what U.S. forces did in Sadr City. Why would the United States assume the current ISF will be able to do so in Mosul?
If the ISF is incapable of defeating ISIL in the cities where it has gone to ground, then the only reliable means available are U.S. ground combat forces. The U.S. Army and Marine Corps are trained and ready for the fight with ISIL. They have all the skills in joint combined arms warfare that the ISF lacks. U.S. Army armor formations should be at the heart of this joint task force, just as they were in Sadr City, to provide U.S. forces with the mobile, protected discriminate firepower that will overmatch and quickly defeat ISIL.
Trying to take Sunni cities with combinations of Shi’a militias, Peshmerga, and ISF forces would also present a challenge. None of these forces would be trusted by the Sunni populations, which might therefore continue to support ISIL. In the eyes of the locals, U.S. ground forces are least likely to have sectarian agendas and, thus, are potentially trustworthy in the eyes of Mosul’s noncombatants.
There is understandable reluctance to deploy U.S. ground forces to fight ISIL, given U.S. experiences since 2003. But, again, this is a different war. It is not unlike the 2004 Battle of Fallujah, where U.S. Army and Marine Corps formations fought a tough urban battle to excise the cancer that had consumed Fallujah. Similarly, the U.S. military objective against ISIL would not be nation-building or counterinsurgency, but to remove ISIL from Iraq. The surest means of attaining this strategic objective is with the introduction of U.S. ground combat forces and the necessary sustainment packages to support them. Politically, this will be extremely difficult given likely Iraqi objections and the substantial Iranian presence in Iraq.
The most difficult political issue, however, is mustering American political will for a U.S. ground commitment against ISIL. The president will have to make the American people understand why a U.S. ground commitment is the only sure means available to achieve our national objectives. The argument is simple. Absent the introduction of U.S. ground forces, the success of the U.S. strategy is inextricably tied to means—the ISF— whose fitness for the task is questionable, as are their increasingly retaliatory methods against Sunnis. If the ISF fails, ISIL will receive a tremendous boost in prestige and recruiting appeal, thus increasing its threat to the region, U.S. allies, and possibly even the homeland. Finally, Iranian influence and presence in Iraq, already significant, would surely increase.
Quite simply, an ISF military failure against ISIL could unhinge U.S. policy in the region. The United States cannot allow this to happen and then contemplate what to do next. The stakes are too high.
David E. Johnson is a senior researcher at the nonprofit, nonpartisan RAND Corporation and an adjunct professor at Georgetown University.