The Pentagon is engaged in a strategic transformation that may imperil the future of American national security. According to a 2018 independent bipartisan commission appointed by Congress, the United States’ preoccupation with counterinsurgency (COIN) and counterterrorism has enabled near peers and rogue states to shrink the capability gap between their militaries and that of the world’s only superpower. Policymakers and the defense community must recognize that great-power competition is not only a test of conventional military strength; it also demands mastery of actions below the major-war threshold that include counterinsurgency, irregular warfare, hybrid threats, stability operations, and the “gray zone.” A COIN capability is critical to American competition and conflict with other states, and war with nonstate actors. The US Army should be careful lest it commit too many resources to high-intensity war. This article surveys the service’s changed approach to readiness and the threat landscape. It then compares the transition from official hostilities to stability operations early in post–Civil War Reconstruction (1865–1866) and Operation Iraqi Freedom (2003–2004) to demonstrate that counterinsurgency requires a heavy commitment to manpower and training.

The Army has not completely abandoned COIN. It retains the capability through doctrine, education, and assistance it provides to other armed forces. The 2018 Army Strategy and 2019 Army Doctrine Publication 3-0, Unified Land Operations affirm that irregular warfare is important—a view echoed by Pentagon officials and an officer self-study webpage. A 2019 article in War Room, the online journal of the Army War College, actually criticizes the counterinsurgency emphasis of the training.

The general trend, however, has been a course correction. Congress and the defense community doubt American readiness for a major conflict. In January 2017, for example, the Army reported only three of fifty-eight brigade combat teams ready for immediate deployment. The result is a growing emphasis on the dangers that China and Russia pose. The 2018 National Defense Strategy declares that “inter-state strategic competition, not terrorism, is now the primary concern in U.S. national security.” More evidence of this shift can be found in the 2018 National Military Strategy, the 2019 Army Modernization Strategy, and the Pentagon purchase of new vehicles and weapon systems. Articles in Military Review, Small Wars Journal, and War on the Rocks note the Army pivot to conventional warfare. The approval of some senior officers and the decreased size of the service facilitate this trend, as does limited funding that adds pressure to prioritize the greatest threats. Given the Army’s renewed emphasis on major war, its response to insurgencies will depend on security force assistance brigades and special operations forces. Its stability operations will involve small deployments, reliance on partners, and prioritizing aid to civilian agencies.

The Army risks forgetting past experience. Comparable doctrines emerged from Vietnam and Iraq, reflecting the Army’s tendency to avoid preparing for occupations, grudgingly adapt to them, and discard the knowledge afterward. Illustrative of growing disinterest in counterinsurgency are generals who regard irregular tasks as a lesser aspect of conventional duties. The Army’s history with irregular operations reveals that COIN requires more resources, but as Capt. Justin Lynch warns, the Pentagon may “acknowledge the importance of counterinsurgency, but not provide enough training or resources to produce an effective force.”

The Department of Defense formally defines COIN as “comprehensive civilian and military efforts designed to simultaneously defeat and contain insurgency and address its root causes.” This article uses it more generally to denote Army activities that promote stability and defeat insurgents. They range from kinetic operations, to enforcing law and order, to winning hearts and minds. These capabilities must remain an Army priority. Navigating the transition from conflict to a condition of stable governance is central to modern warfare. Maintaining a counterinsurgency capability is essential for this mission and reflects the fact that the defense community cannot remove this option from the ones available to policymakers. Concentrating exclusively on conventional fighting implies that America can choose its conflicts, an assumption disproven by history. Irregular operations have imposed a heavy toll in casualties, money spent, and reputation lost. Roughly four-fifths of global conflicts since 1815 have been either civil wars or insurgencies; there were 181 of the latter from the Second World War to 2015. Between 1798 and 2018, nearly three-quarters of American operations abroad were irregular, while one-fourth were conventional. Being unable to wage such campaigns reduces the service’s deterrent effect and American influence in unstable, strategic regions.

Critics of this view might argue that many of these counterinsurgencies were wars of choice as opposed to wars of necessity. The problem with this thinking is that states choose to wage war in order to advance their interests. A conflict may appear unnecessary in hindsight, but policymakers at the time regarded it as a national imperative. As military historian Sir Michael Howard wrote, the primary motivation for warfare over the past two centuries has been the ability of humans to “discern, or believe that they can discern, dangers before they become immediate.” Focusing solely on unavoidable wars deprives the Army of capabilities, giving the initiative to hostile actors and thus weakening American foreign policy. The service will struggle to shape the threat environment if it is unable to intervene short of large-scale combat operations.

The ability to win a high-intensity conflict does not produce victory in a counterinsurgency, which frequently involves unique challenges. Army preparations must account for the fact that it will operate among civilians, and that rivals will combine regular and irregular warfare. Moreover, they will support insurgencies to avoid confronting America’s conventional overmatch. China, Iran, North Korea, Pakistan, and Russia have either fostered such conflicts or can do so. Nonstate actors, with improved access to information and technology, form globally connected insurgencies that elude defeat by moving from one country to another. Articles in Foreign Policy, Military Review, Small Wars Journal, and War on the Rocks affirm the relevance of COIN; insurgencies will be strategically important to great-power competition.

A comparison of Reconstruction and Operation Iraqi Freedom informs Army planning by revealing that ample manpower and consistent conduct are critical to success . The service will not have enough appropriately trained officers and soldiers if it sidelines counterinsurgency in favor of conventional war.

Troop Numbers

The Army during Reconstruction formed “a patchwork of sovereignties” across the South due to limited manpower. There were approximately one million Federals in uniform as of April 1865, the month the Civil War ended, but that number would drop quickly and dramatically. The number of troops overseeing Reconstruction shrank from about 190,000 in September of that year to roughly twenty-five thousand by December 1866. Available data indicates that this was a demanding assignment. In 1867, for example, the service numbered fifty-seven thousand, and over two-fifths of its companies were stationed in the South in the winter of 1867–1868. The Army force level for Reconstruction was too small for two reasons. First, it was attempting to control a population of nine million people in a territory that equaled the combined size of France, Germany, Italy, Spain, and the United Kingdom. Second, it ruled by martial law for most of this period, functioning as “a relief agency, a police force, a court, a public works bureau, and a school system.” The service’s constrained military means were a poor fit for its sweeping political powers. Stability crumbled with troop reductions, and resistance developed in areas devoid of Federals. Whereas soldiers once deterred violence by occupying county seats and towns located at major crossroads, shrinking numbers forced them to cede many rural areas to planters, and left civilians vulnerable to criminals. Many Southern whites engaged in terrorism that targeted the economic and political activity of freedpeople and loyal whites. They burned churches; attacked, sued, and killed soldiers; intimidated and assaulted loyal whites to expel them; seized the property of former slaves; and unleashed violence on them, resulting in hundreds of murders. By the end of 1866, much of the South collapsed into “near-statelessness.”

A century and a half later, the issue of insufficient troops likewise hindered the Army from quashing the insurgencies in Iraq, a country larger than California with a population of twenty-five million people. Force levels dropped from nearly 153,000 at the close of fiscal year 2003 to around 102,000 in September 2004.The Army numbered just under five hundred thousand in total between 2003 and 2004; hence, Operation Iraqi Freedom imposed a heavy burden by absorbing between 20 and just over 30 percent of the service’s available manpower. Soldier density varied widely, which frustrated efforts to defeat the enemy as well as to secure the borders, perform constabulary duties, seize weapons caches, handle detainees, and train Iraqi soldiers. There were shortfalls of interrogators, military police, Arabic linguists, interpreters, military intelligence assets, construction units, civil affairs personnel, and engineers. The dearth of combatants limited face-to-face interactions with Iraqis and helped drive some units to act on emotion rather than conducting the careful efforts required to build popular support and minimize collateral damage. Perhaps most importantly, there was usually no operational reserve in theater. It was impossible to balance troop distribution between the center of Iraq and its border areas, which enabled the insurgencies to grow. Units occupied areas until enemy activity faded and then moved on, which allowed the latter to retake those locations. Filling gaps, moreover, required pulling forces from elsewhere, so there were too few soldiers in key zones. Small units lost control of some hostile areas, other communities without large bodies of troops witnessed a decline in Iraqi security capability and greater Sunni-Shia tensions, and towns fell to insurgents due to inadequate protection. In at least one instance, it proved necessary to draw on a corps reserve that could not be reformed for lack of manpower.

Ground-Level Practice

The Army’s ground-level conduct was uneven during Reconstruction, an issue for which officers were largely responsible. Some suspended civil courts yet did not establish military ones for several months. They had flexibility in writing their own rules for legal appeals, and in creating provost courts that at times dealt with the cases of freedpeople. There were disagreements within the Army about the meaning of freedom for former slaves; while officers favored written labor contracts for them, another idea was for them to buy land over time. Support for the creation of area militias was not universal. Lenient officers allowed local authorities to remain in office, worked so that ex-Confederates could serve in that capacity, promoted elections, established police companies, and distributed instructions to facilitate interaction between ex-slaves and their prior owners. Other examples of this behavior included the offering of transport for ex-Confederate soldiers, loaning of draft horses to impoverished farmers, providing shelter and food to white and black refugees, and establishing an affairs bureau for former slaves. Heavy-handed officers repressed newspapers, forbid the continued service of ex-Confederates in local offices, chose new authorities, suspended biased laws, determined election outcomes, and ordered militias to obey Army commands. They even tested civilian loyalty, arrested the unpatriotic, and forbid the public’s use of the word “Confederate.”

The Army in Operation Iraqi Freedom also had an inconsistent approach to counterinsurgency. Some units focused on destroying the enemy by adopting relaxed rules of engagement and performed nighttime cordon-and-search operations that detained large numbers of suspects. Other outfits, however, emphasized nation building. This conciliatory approach involved improved interaction with locals and concentrated on safety, employment, economic recovery, essential services, and governance. It featured more precise operations, less obtrusive cordon-and-search operations, a greater reliance on civil affairs teams, and the fielding, sustaining, and use of new Iraqi army and police units as well as Iraqi Civil Defense Corps outfits. Further inconsistencies occurred in the use of artillery. Approaches ranged from counterbattery fire to the combination of counterfire, intelligence collection, and encouraging locals to ensure enemy forces did not take up position on their land.

The True Cost of COIN

The examples of Reconstruction and Operation Iraqi Freedom demonstrate that counterinsurgency imposes a heavy burden in terms of force levels and preparation. Special operations forces and security force assistance brigades are too few in number to occupy an extensive territory akin to the American South or the smaller yet more populous Iraq. Restricting COIN capability to situations in which the Army supports a host government—rather than leading the effort—ignores fragile states that struggle to ensure effective rule and their citizens’ safety. A large-scale conflict would leave such countries in disarray, necessitating massive counterinsurgency operations.

This raises the question: How should the service commit most of its funding, time, and resources? The answer depends on the assessment of future threats. High-intensity conflict with China or Russia is the most dangerous outcome, since defeat in the worst case might imperil the American homeland. And yet, this observation could be made of any substantial military rival that the United States faces, past or present. In a more probable scenario, those countries would wage wars so costly that America would allow them freedom of action in their areas of influence. The most likely situation, however, is the recurrence of insurgencies, since they have been more common historically than conventional wars. The Army should prepare for future conflict based on this reality rather than falling into the cyclical trap of retreating intellectually from its most recent COIN experience.

America has an expensive track record with counterinsurgency, suggesting a weakness that China and Russia could exploit. The post-9/11 conflicts—in Afghanistan and Iraq—cost the United States about $1.5 trillion as of 2015. This is slightly more than its financial burden in the First World War and the Korean, Vietnam, and Persian Gulf wars combined. It may appear that the country can afford such conflicts for years to come, as defense spending only represented 3.2 percent of the gross domestic product in 2018. And yet, the staggering reality of a $984 billion national deficit and $22 trillion national debt in 2019 will surely temper excessive military expenditures. Likewise, the current coronavirus pandemic presents the risk of a major economic downturn that could curb defense spending. The financial cost of COIN is a reminder that a failure to prepare forces the Army into the expensive and time-consuming process of adapting on the fly. Long conflicts are expensive ones, and shortening future counterinsurgencies will only be possible if the service has a well-honed capability.

Assessing near-peer threats requires thinking outside the conventional warfare box. Why would China and Russia risk conventional conflict with America when they could foment insurgencies or perpetuate existing ones in places of strategic significance? The Soviet Union and the United States did so in Vietnam and Afghanistan, respectively, to weaken one another during the Cold War. Now, the leaders of China and Russia enjoy the advantage of being able to craft a long-term strategy, one that could depend on the attritional effect of counterinsurgency campaigns to reduce the military strength of the United States. Chinese president Xi Jinping can rule indefinitely and Russian president Vladimir Putin is working to do so. Americans elect a new president every four years, however, which can complicate the efforts of US policymakers to craft an enduring strategy.

The Army must balance the national security issue of the moment and the areas that will be most important over the coming years. It should hone its COIN capacity as part of a comprehensive effort to ensure readiness for missions below the major-war threshold. Failing to do so makes counterinsurgency an American vulnerability that near peers will exploit for asymmetric advantage. Restricting Army readiness to conventional war limits the military options available to policymakers, increasing the risk of escalation with a belligerent adversary. The service needs to be prepared for everything from conventional war to COIN, irregular warfare, hybrid threats, stability operations, and the “gray zone.” The ability to engage America’s enemies across the full spectrum of warfare is the only way that the Army can rightfully claim to be the premier land-fighting force in the world. As a superpower, the United States has global commitments. It must be able to deter, and if necessary, defeat a broad array of adversaries with wide-ranging means of aggression. A strong counterinsurgency capability will be essential.


Alexandre F. Caillot is a PhD Candidate at Temple University specializing in American military history. His dissertation examines the Civil War, namely the combat performance of Union soldiers who entered the Army of the Potomac in time to serve during the Overland Campaign. He is a Junior Fellow, Program on National Security, at the Foreign Policy Research Institute.

The views expressed are those of the author and do not reflect the official position of the United States Military Academy, Department of the Army, or Department of Defense.

The author would like to thank the following individuals for unofficial conversations that do not represent the official views of the US Army: Dr. Conrad C. Crane; Brig. Gen. (ret) Duke DeLuca; Col. (ret) Paul C. Jussel, PhD; Dr. Christian B. Keller; Col. Jon Klug; Maj. Mark Morrison; Col. Matthew D. Morton; Col. Dave Raugh; and Col. (ret) Frank Sobchak. The author would also like to thank Dr. Michael Noonan for offering statistical information from a forthcoming publication on the number of US irregular and conventional operations abroad between 1798 and 2018.


Image credit: Staff Sgt. Stacy L. Pearsall, US Air Force