Ryan C. Van Wie
States rarely predict what their next war will look like. However, the choices they make regarding their military force structure have a lasting impact on their capabilities in future conflicts. This is clearly seen in the case of Russia, where systematic weaknesses in force structure, including dismounted infantry, logistics, and command and control have hindered the tactical effectiveness of Russian ground forces in their ongoing invasion of the Ukraine.
While there is consensus that force structure decisions are consequential in both conventional and civil conflict settings, there is a noticeable gap in the counterinsurgency (COIN) literature between practitioners and scholars when it comes to defining the ideal counterinsurgent force structure. On one hand, COIN practitioners in Iraq and Afghanistan found mechanized units to be critical in surgically targeting and defeating well-armed insurgents. On the other hand, some COIN scholars argue that dismounted units make superior counterinsurgents, finding that mechanized units are not ideally structured for COIN, struggle to exploit local intelligence, and have the propensity to increase civilian casualties. Resolving this analytic divergence between scholars and practitioners is important and shapes enduring deliberations on the appropriate balance between light and heavy forces.
To examine this puzzle, my co-author Jacob Walden and I explored how heterogeneous US and UK forces structures impacted counterinsurgency operations during Operation Iraqi Freedom (OIF) in recent articles in Small Wars and Insurgencies and the Journal of Conflict Resolution. We leveraged US and UK OIF unit rotational policies to test empirically how force structure differences impact COIN dynamics. Taken together, both articles suggest that a more nuanced view is required to properly assess how military force structure considerations impact local insurgency dynamics. Beyond focusing solely on counterinsurgent force structure (i.e., mechanization), we argue force structure should always be considered alongside force employment.
Force Structure and Civilian Casualties
In the first paper, we quantitatively evaluate how counterinsurgent force structure affects civilian casualty levels in OIF from 2004-2008. While recent studies have focused on the impact of airstrikes in causing civilian casualties, the role of ground forces in producing civilian casualties is understudied. This is problematic, because data from OIF indicates Coalition ground forces triggered 62% of government-caused civilian casualty incidents. To analyze the impact of counterinsurgent force structure on civilian casualty rates, we leveraged the Empirical Study of Conflict’s Iraq Civil War Dataset (v3) and Dr. Carrie A. Lee’s Iraq Order of Battle Dataset. Alternate would be expanding this to a sentence: “Our panel dataset captures mechanization levels down to the battalion level, within each Iraqi district, per month. Our quantitative findings suggest mechanized counterinsurgent units caused fewer civilian casualties compared to dismounted units, likely sparing hundreds of Iraqi civilians between 2004-2008.
To address the practitioner-scholar gap mentioned earlier and to underpin our suggestive quantitative findings, we develop the armored restraint theory. This theory proposes that enhanced protection provided to armored crews gives them additional time and safety when using lethal force in a direct fire engagement. We further suggest that mechanized counterinsurgents who adhere to the laws of armed conflict may be able to reduce unintentional civilian casualties compared to their dismounted counterparts.
We propose three primary mechanisms to explain how the armored restraint theory functions at the crew level and results in lower civilian casualty rates. First, US and UK armored vehicle crews in OIF had access to mechanically stabilized, precision machine guns. When engaging insurgents in a populated area, these advanced weapon systems provided increased precision and accuracy compared to the variants used by dismounted units. Second, the hierarchical decision-making within an armored crew allowed for leader verification before the employment of lethal force, potentially preventing harm to civilians. In contrast, a dismounted unit, lacking protective armor and driven by self-defense imperatives, would immediately return fire to suppress known and suspected enemy positions, potentially endangering local civilians. These risks may be amplified if the dismounted unit is forced to call in artillery or attack aviation. Finally, US and UK armored vehicles offered increased crew protection during engagements against insurgents lacking modern anti-tank guided missiles. Psychology research suggests this increased protection, along with additional decision-making time, gives armored crew members an advantage during high-stress firefights, compared to their dismounted counterparts.
Together with the quantitative findings, this causal logic helps explains how US and US armored units were associated with lower civilian casualty rates, compared to dismounted and motorized units. Marius Mehrl’s recent analysis aggregating data across numerous conflicts between 1986-2016 finds that mechanization levels are not significantly related to government-caused civilian casualty rates. It is important to note that these quantitative findings are narrowly focused on force structure’s impact on civilian casualty rates. They do not address the broader association between armored units, tactical and operational effectiveness, and counterinsurgent outcomes. Our next paper explores this question, by including counterinsurgent force employment as an important variable that was omitted from earlier analysis.
Force Structure, Force Employment, and COIN Effectiveness
In the next article, we partially reconcile divergent practitioner and scholar perspectives by considering mechanization’s ideal role in the sequential stages of a clear-hold-build campaign. We propose a new adaptive counterinsurgent force employment hypothesis that highlights the tradeoffs between higher-risk dismounted operations and the benefits of dismounted information collection, conditioned on the local insurgent strength. This hypothesis suggests that mechanized forces can provide significant benefits to counterinsurgents when clearing areas with high-strength insurgents, outweighing the befits of dismounted civilian interaction. However, following successful clearance operations, when government control is increased and insurgent strength is reduced, the need for armored protection diminishes, and information provided by civilians becomes decisive in targeting the remaining insurgents who blend in with the population. Therefore, during the hold and build stages, counterinsurgents should increasingly rely on dismounted troops.
To test our hypothesis, we explore how mechanization impacts COIN effectiveness in local contexts using case studies from the Iraq War. This conflict offers a unique opportunity to study the impact of mechanization, as US and UK light, motorized, and mechanized units regularly deployed and fought in Iraq. We explore how counterinsurgent force structure and force employment impact COIN effectiveness. Our qualitative findings in this project suggest that force employment is the critical determinant in COIN effectiveness, not force structure.
In our most prominent case, we analyze the 1st Armored Brigade Combat Team, 1st Armored Division’s (1/1 AD) 2006-2007 deployment to Ramadi, Iraq. Despite 1/1 AD’s heavy force structure, centered around M1 Abrams tanks and M2 Bradley infantry fighting vehicles, the brigade achieved tactical COIN success through adept force employment. When 1/1 AD first arrived in Ramadi, insurgents controlled most of the city, and close to 100 insurgent attacks were recorded daily, making it one of the most violent locations in Iraq at the time. The armored vehicles of 1/1 AD played a critical role in clearing insurgents from Ramadi and repelling subsequent attacks. However, recognizing the changing conditions on the ground, the brigade adapted its approach. As 1/1 AD and Iraqi Security Forces regained local control, the brigade increased dismounted patrols and established 12 outposts throughout the city to safeguard civilians from insurgents. Over the course of 1/1 AD’s nine-month deployment in Ramadi, insurgent violence steadily declined, local control was maintained, and remaining insurgent cells were gradually targeted with the assistance of local intelligence.
Flexibility Remains Paramount
Taken together, both papers demonstrate that military force structure’s impact on counterinsurgency dynamics is more complex than previously understood. Recent research by Fausto Scarzini and Marius Mehrl complements these broad findings. This analysis is not intended to undercut the critical importance of dismounted counterinsurgents. Dismounted forces still have a vital role to play in engaging with the population, gathering local intelligence, and selectively targeting insurgents hiding amongst local civilians. Rather, our findings suggest that mechanized units can play an important, if limited, role as counterinsurgents, especially when operating in the “clear” and “hold” phases against well-armed insurgents. Furthermore, the flexibility of force employment, tailored to local conditions, appears to be more influential than force structure alone, as observed in case studies of mechanized units during OIF. Local geography, civil and economic considerations, insurgent strength, and civilian disposition are all critical factors when considering how to employ counterinsurgents, and which types of forces to employ.
Having intelligent, adaptable leaders who understand these crucial local factors and can flexibly adjust force employment is another key to successful tactical adaption. This point on leader education is particularly relevant 20 years after the start of OIF in 2003. As we reflect on the lessons learned during the past two decades, it is noteworthy that US military doctrine largely overlooks force structure considerations and fails to capture the nuanced ways in which different unit types could ideally be employed in counterinsurgency operations. For example, in DoD’s Joint Publication 3-24, Counterinsurgency, the “Employment Considerations” subsections covering “Task Organizing for COIN” and “Conventional Forces Considerations” do not consider the nuances of mechanized versus light forces. Perhaps more surprisingly, the US Army’s Field Manual 3-24 Insurgencies and Countering Insurgencies, lacks a discussion on how force employment could vary based on the type of unit and their associated strengths and weaknesses.
To ensure that future generations are better equipped to confront similar challenges, it is crucial that these hard-earned lessons from Iraq and Afghanistan find their place within military doctrine. By integrating the insights gained from these experiences, we can foster a more comprehensive understanding of force structure, force employment, and what it takes to be successful in counterinsurgency operations.
Ryan C. Van Wie is a US Army Infantry Officer and previously served as an assistant professor of international affairs in the Department of Social Sciences at the United States Military Academy. He holds a Bachelor of Science from the United States Military Academy and earned his Master of Public Policy from the University of Michigan, Ann Arbor.
Main image: Tarmiya, Iraq (March 28, 2006) – U.S. Army Spc. Osvaldo Fernandez stands perimeter security in front of an M1114 HMMWV (Humvee) near the town of Tarmiya, Iraq during counter-insurgency operations. U.S. Navy photo by Photographer’s Mate 1st Class Michael Larson