Reducing the Human Cost of Large-Scale Military Operations


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| Jul 3, 2023


Editor’s note: The following post highlights a subject addressed during an expert workshop that the Lieber Institute co-convened alongside Harvard Law School’s Program on International Law and Armed Conflict and the International Committee of the Red Cross, focusing on some of the legal issues arising in large-scale combat operations. For a general introduction to this symposium, see Winston Williams and Jennifer Maddocks’ introductory post.

Although non-international armed conflicts (NIACs) dominated the attention of Western policymakers, practitioners, and academics in recent decades, international armed conflicts (IACs) have hardly remained a thing of the past. It therefore comes as no surprise that States would seek to provide strategic direction to their armed forces to ensure readiness for a full spectrum of operations including large-scale military operations.

However, it is important to recall that armed conflicts, including those that involve large-scale military operations, are not inevitable. As the International Committee of the Red Cross (ICRC) has reiterated elsewhere, States should invest far greater efforts in avoiding conflicts in their different manifestations and take great care that their “preparedness” does not become a self-fulfilling prophecy. When wars do break out, however, international humanitarian law (IHL), which was codified in the aftermath of high-intensity armed conflicts, applies to both IACs and NIACs. States and non-State armed groups must comply with IHL irrespective of the scale, intensity and speed of operations that ensue.

As part of its international mandate to work for the faithful application of IHL, including States’ obligations to prevent IHL violations and protect those affected by armed conflict, the ICRC seeks to draw States’ attention to the need to anticipate and minimize the human cost of armed conflict. In this post, the authors highlight some of the unique circumstances generated by “Large-Scale Combat Operations” (LSCOs) which have been the recent focus in the U.S and among some of its partners. The post also introduces some non-exhaustive considerations for those directed to prepare for and, in the worst case, conduct such operations.

What States Appear to Refer to When They Use the Term “LSCO”

It is important to clarify that “LSCO” is not a legal term that exists under IHL. Nor does the term “LSCO” serve to clarify the norms that would govern such an operation, or even how those norms should be interpreted. Rather, “LSCO” is a military doctrinal concept that is commonly used by the United States and some others to refer to military operations associated with high intensity warfare.

According to the description of “LSCOs” offered in Field Manual 3-0 Operations (2022) (1-46), they are “extensive joint combat operations in terms of scope and size of forces committed.” During ground combat, they “typically involve operations by multiple corps and divisions” along with “substantial forces from the joint and multinational team” and “often include conventional and irregular forces on both sides.”

Based on this doctrinal description, arguably, “LSCOs” have taken place in several international and non-international armed conflicts this century and last. Take, for example, current operations in Ukraine and Sudan, as well as recent high intensity hostilities during the conflicts in Tigray, Nagorno-Karabakh, Syria, Iraq, and Yemen. The term encompasses numerous operations in multiple theaters of the First and Second World Wars, the Chinese Civil War (1927-36), the conflicts in Indochina (1946-54) and Việt Nam (1955-75), the Korean War (1950-53), Arab-Israeli Conflicts (e.g., in 1948, ’56, ’67, ’73); the Gulf Wars (i.e. 1980-88, 1990-91, 2003), Sino-Vietnamese War (1979), Israel-Lebanon War (1982), and both Chechen Wars (1994-96; 1999-2000).

The ICRC has been present in most of the above-mentioned conflicts, often working in conjunction with the respective National Red Cross/Red Crescent Societies to provide some level of protection and assistance to those affected. In many of these places, the ICRC stayed long after those “LSCOs” came to an end because, in the aftermath of high intensity battles and conflicts, the human suffering, devastation, and insecurity always endures.

To be clear though, the parties to an armed conflict bear the primary responsibility to provide for the basic needs of the civilian population under their control. While humanitarian actors play an important role, it is indeed a subsidiary one. As we discuss later, the scale and complexity of the humanitarian needs caused by “LSCOs” will almost certainly go well beyond the technical, practical, and financial capacities that can be mustered by a collective humanitarian response.

Considerations For Those Directed to Prepare For and Conduct “LSCOs”

Much has changed since past “LSCOs” from even as late as the last century. Aside from advancements in means and methods of warfare, a significant amount of infrastructure is shared by both militaries and civilians today, and much more is known about the human cost of conflict. The legal framework and public expectations of warring parties has evolved too.

Below are some non-exhaustive legal considerations as they relate to so-called deep, close, rear and consolidation operations (in line with the doctrinal operational framework that we understand to be common across many militaries). They are aimed primarily at commanders, operators, and lawyers.

Deep Operations: Multi-Domain Targeting

Operating at the juncture between tactics and operations in large-scale ground combat operations, we hear often that divisional and corps headquarters staff will be presented with legal and operational challenges when aiming to mitigate civilian harm while simultaneously seeking to shape the deep fight, control the close fight, and protect rear areas from disruption and destruction by the adversary.

Coordinating and synchronizing the lawful employment of multi-domain capabilities for operations aimed at targeting an adversary throughout its depth will undoubtedly call for command and staff officers to visualize future operations in greater depth in time and space (p. 73) and demand extensive planning (see also FM 3-0 (3-29)). Among other reasons, such planning is crucial for reducing risks such as large-scale death, injury, destruction and other harm to civilians and civilian objects including the natural environment. Such risks are especially acute when conducting, for example, long-range fires, interdiction operations, cyberspace and space operations, and military information support operations.

Lawyers advising headquarters staff involved in joint and combined deep targeting will need to be technically proficient and structurally enabled to provide principled counsel on complex IHL questions, as well as legal interoperability challenges as they specifically relate to deep operations. For example:

– How to ensure lawful target selection and proportionality assessments? Deep operations raise concerns that belligerents may adopt an overly broad interpretation of the military objective definition to justify either sweeping or anticipatory target classifications or attacks not for the purpose of degrading an adversary’s military capabilities but rather for political or economic reasons. As for proportionality, important questions remain as to the limits imposed by the requirement that anticipated “military advantage” be “concrete and direct.”

– If situational awareness is expected to be degraded at the range in which deep operations occur, when are those who plan and decide upon attacks deemed to have taken all feasible precautions required for both target verification and incidental harm assessment (i.e., bearing in mind the latter demands an assessment of all reasonably foreseeable direct and indirect effects)?

– What is required for States to meet their obligation to take all feasible precautions in the choice of means and methods of warfare? For example, how might such considerations influence requests for and/or allocation of joint and combined capabilities? It must be emphasized that, despite there being no general obligation to always use or acquire the most precise or modern capability, and irrespective of any supply chain issues that may arise during an “LSCO,” if the only way to conduct an operation without violating the prohibition of indiscriminate or disproportionate attacks is to use a specific capability, there are two options: use it or don’t carry out the attack at all (ILA, p. 383-4).

Preparedness for lawful multi-domain targeting—especially at echelons above brigade—calls for realistic and demanding training. That training must go further than the standard brief on principles and rules of IHL. Rather, these rules and principles must be operationalized, including through well-calibrated and exercised targeting authorities, delegations, and standard operating procedures. These are all essential for striking the careful balance needed for responsible “mission command” and command responsibility.

Providing such training can be difficult because, for many militaries, it seems impossible to train entire divisions, let alone corps, physically in the field, at distance and over time, and alongside coalitions and partners. Nor can one ever truly replicate the impact of large-scale military operations upon the civilian population, infrastructure and the natural environment during training, despite realism being an essential component of quality training.

Of course, professional military education, command post exercises, wargames, and synthetic/virtual training environments are useful for thinking through legal and humanitarian challenges. Such activities are most effective when designed in such a way that ensures realistic civilian harm considerations are deeply embedded throughout and, where possible, humanitarian actors can be involved in the discussions. Ensuring that legal lessons learned from previous operations are widely disseminated, including in relation to both immediate and long-term civilian harm, is also essential.

Beyond this, it is critical to ensure effective legal review processes for new weapons, means and methods of warfare that rely on new technologies, such as military cyber capabilities or autonomous weapons systems. These processes should inter alia enable review at an earlier stage of development, and at shorter intervals, than for more traditional technologies, and should allow for the reviews to be repeated during development (ICRC, p. 34-45).

Close Operations

We hear often that “the intensity and high stakes of LSCOs are likely to necessitate more targeting decisions, made by fewer people, in less time, based on minimal information.” This is especially the case for those tactical elements conducting close operations (e.g., Brigade Combat Teams and below). It is expected that formations will be dispersed, always maneuvering for survivability, they will be deprived of a large military intelligence footprint affording sophisticated fusion and collection capabilities, and that reach back to higher echelon support (including legal support) will be severely constrained or not available at all.

Despite this, as others have noted, when human terrain becomes increasingly dense, the need to secure organic intelligence from it will expand. This is not only to enable tactical echelons to maneuver but also to protect civilians from the effects of hostilities (e.g., securing routes for safe passage of civilians and evacuation of the wounded, sick, detained, and dead, and identifying suitable passive precautions in populated areas).

Similarly, the sheer amount and complexity of data that tactical units collect will call for skilled military intelligence personnel to monitor sensors and, in turn, identify and prioritize trends and anomalies (e.g., information on evolving needs, vulnerabilities, sentiment of civilian population) for transmission to higher echelons to enable the latter to better prepare for rear and consolidation operations. Automation can help with understanding the civilian picture; however, there are also clear limitations in this regard (e.g., p. 71).

Ensuring commanders and operators, at all levels of operations, are provided with more information to better understand how civilians respond to and are affected by conflict is critical to respect key IHL obligations. This is consistent with the political commitments to better protect civilians from the use of explosive weapons in populated areas made by more than 80 countries, and the U.S. Department of Defense Civilian Harm Mitigation and Response Action Plan (objectives 3 and 4). It is also a priority ICRC recommendation for political authorities and commanders in both States and non-State armed groups.

If the assumption is that tactical commanders in close operations will be delegated broad authority to make decisions that pose significant risk of harm during “LSCOs,” these same commanders must not be starved of the information and training necessary to understand the civilian environment and make decisions in a manner consistent with legal and policy commitments. In addition to providing quality legal training, armed forces must ensure that the training, equipping, and staffing of military intelligence elements, as well as the analytical methodologies they use, are fit for purpose, especially at the tactical level.

Regardless, even when tactical elements are operating within a high tempo and information deprived environment, an intuitive commander should recognize that yesterday’s deep area of operations could very well be today’s close, and tomorrow’s rear. Therefore, it is critical they take all possible measures to anticipate and mitigate the civilian harm they are likely to encounter in their respective areas of operations.

Consolidating Gains and Rear Operations

Preparations for armed conflict, and especially “LSCOs” that result in widespread civilian harm, require complex military and interagency activities in rear areas that are shaped by deep operations and occur concurrently with the close fight (p. 19). Additionally, activities behind the forward line of own troops, or in the “spatial—and often temporal—wake of LSCOs,” that consolidate gains can be essential to achieve strategic goals within a campaign.

Even more importantly, several of these activities are crucial for upholding respect for IHL during armed conflict, including in occupied territory, and in the aftermath. They require planning, resource allocation, and coordination across different parts of a State to foresee and prepare for the full range of likely harm at all levels. This often requires complementing the security lens with a civilian perspective.

This means anticipating the need to care for the wounded and sick, detention operations, mass population movement and displacement, management of the dead and clearance of explosive remnants as predictable consequences of war. It entails getting to grips with the reality that civilians do not behave as a monolithic group, and planning for variation based on age, gender, and disability. It requires establishing processes to account for the separated, the missing and dead, and for the conduct of effective investigations into possible IHL violations. It also means respecting independent and impartial humanitarian action by inter alia allowing and facilitating rapid and unimpeded passage of humanitarian relief to affected territories subject to the party’s right of control; recognizing humanitarian carve outs to sanctions regimes; providing access to basic needs; restoring access to essential services; and enabling reintegration and resettlement of the displaced. When in occupied territory, it includes inter alia making every effort to restore and maintain public order and civil life. It means leveraging support relationships to ensure respect for IHL including through responsible exit strategies.

Similarly, strategic guidance to commanders must be that these essential tasks are key priorities when raising, training, and sustaining personnel and capabilities, as well as during early campaign planning. They must be more than simply an afterthought, “tacked on” at the end of an exercise or miliary-decision making process. Nor are they tasks that can be simply delegated to Civil Affairs, noncombat specialty units, or legal advisers.

The remainder of the post addresses some non-exhaustive considerations that require specific attention related to population movement, detention operations, the provision of basic needs, and facilitating humanitarian access.

Anticipating Population Movement and Detention Operations

Mass population movement, screening operations, as well as the capture and detention of individuals, on land or at sea, are likely to trigger complex legal and operational issues. These might concern the legal status of individuals, accounting for persons, the grounds and procedures for detention, ensuring capacity to meet age, gender and disability-based needs and related legal obligations, as well as the location and duration of detention.

Such a scenario is likely to generate consequences that would exceed humanitarian response capacities. One can expect gaps in accounting for persons; large numbers of separated and missing persons; inadequate conditions of displacement and detention including overcrowding and insufficient access to basic needs (food, medicine, accommodation); lack of attention to humane, non-discriminatory treatment for those at particular risk (e.g., children, the wounded, persons with disabilities); threats to physical and mental wellbeing; lack of communications with the exterior increasing individuals’ anxiety and vulnerability etc. Unless anticipated and prepared for in advance, the scale and speed of such operations could pose significant challenges to ensuring adequate conditions, conducting periodic reviews of internment, ensuring safeguards in criminal detention, and respect for the principle of non-refoulement in transfers between States and/or non-State armed groups.

This underscores the importance of foresight and preparedness coordinated across multiple governmental departments through effective and well-resourced systems and processes, and interoperability with partners, proxies and allies, to address consequences beyond the conduct of hostilities. For example, in addition to facilitating ICRC visits to those detained in relation to armed conflict, the Geneva Conventions foresee an obligation for States to set up National Information Bureaux, and to cooperate with the Central Tracing Agency with a view to accounting for protected persons in their hands, prevent them from going missing, and inform their families of their fate and whereabouts (GC III, arts. 122, 123; GC IV, arts. 136140; AP I, art. 33(3)).

Provision of Basic Needs and Facilitating Humanitarian Access

Widespread death and injury to civilians and combatants can be anticipated, giving rise to extensive demand for medical care and dignified management of the dead. Fighting would undoubtedly move to urban areas and devastation from explosive weapons with a wide impact area is expected. Homes and critical infrastructure may be destroyed or rendered inoperable. The compounding direct and indirect effects of the fighting often lead to long-term disruptions to essential services such as electricity, healthcare, water and sanitation, food production and distribution, as well as education; they also degrade the natural environment in a manner now frequently aggravated by climate risks. Hunger and food insecurity, both within the States involved in the armed conflict and beyond, may be exacerbated by the fighting. Even after armed conflict ends, unexploded ordnance and other explosive remnants of war, may continue to threaten the safety, health, and livelihoods of persons affected for years and sometimes decades.

Too often, incorrect assumptions are made about humanitarian actors’ response capacities, how civilians will react during armed conflict and the extent of their vulnerabilities. The scale of the consequences amid the failure of interconnected and interdependent essential services will likely exceed that which can be addressed by humanitarian action alone. In the absence of functioning health services and humanitarian actors, civilians are expected to seek out militaries for medical care and provision of basic needs. Recalling that the primary obligation of parties to the armed conflict is to meet the basic needs of populations under their control, militaries must be prepared to carry out this work that they may have become accustomed to delegating to humanitarians.

Both capacity constraints and challenges to upholding principled humanitarian action could limit the ability and at times the willingness of humanitarian actors to engage.

As militaries know all too well, “logistics doesn’t just happen” and the same rings true for humanitarian operations. We anticipate unbearable pressure on humanitarian logistics hubs, affecting the speed and quality of the delivery of humanitarian assistance. The challenges could be exacerbated by disruptions to the supply chain at the global and regional level, as well as the possibility that resources at the local level might be directed by the parties to the conflict towards supporting the war effort.

Humanitarian organizations will have limited capacity to operate across large swaths of territory and in multiple domains which, in turn, poses challenges to assessing and responding to the needs of those affected. Given the intensity and pace of the fighting, humanitarian pauses and corridors will be essential for humanitarian organizations to carry out their work. These measures are only possible with agreement between the parties to the conflict. However, as is so often the case, they are reluctant to do so out of fear that their adversary will use the pause as an opportunity to re-position, resupply, or conduct other operations.

This is all against the backdrop of the challenges that humanitarian organizations already face in almost every armed conflict. Their ability to respond has been severely restricted due to wholesale denials of access or the imposition of legal and bureaucratic impediments that significantly impede and delay humanitarian action. Humanitarians themselves may be mired by information and communications blackouts which hinder necessary communication within their own organizations, and also externally for critical matters such as obtaining security guarantees and humanitarian notification. Misinformation, disinformation, and hate speech against humanitarian organizations may undermine perceptions of their impartiality, independence, and neutrality. Risks posed by weapon contamination or the effects of belligerents’ mobility/counter-mobility operations can also hinder the safe movement of both humanitarian personnel and civilians.

This underscores the importance of parties to an armed conflict on the one hand preserving humanitarian space and ensuring respect and protection for humanitarian actors as required under IHL, while on the other, preparing to take on some of the roles that were traditionally assumed by humanitarians. Even more than for other conflicts, in “LSCOs”, States must integrate a humanitarian response capacity within their armed forces and possibly even beyond that.

Concluding Thoughts

Defense and military experts have warned against being seduced by the lexicon that tends to permeate current “LSCO” discourse such as convergence, cognitive paralysis, and dilemma. Setting buzzwords aside, let’s make no mistake about the devastating impact of these operations. Throughout history, large-scale military operations have rarely proved to be short, sharp and decisive affairs. In fact, more often than not they are grinding battles consisting of devastating levels of “human and material attrition” resulting in chaos, fear, violence, suffering, deprivation, uncertainty, and fatigue. This impacts not just the warring parties but also those affected by such operations—notably the civilian population, humanitarians, and the natural environment —and endures long after the combat ends. It is therefore incumbent upon all States to invoke the preventive power of the Geneva Conventions and uphold the global consensus and commitment, codified in the aftermath of high intensity conflicts, to avoid or at the very least minimize the human cost of war.


Lakmini Seneviratne is the Head of the Legal Department at the ICRC’s Regional Delegation for the United States & Canada.

Abby Zeith is a Legal Adviser in the Arms and Conduct of Hostilities Unit in the ICRC’s Legal Division.

Kosuke Onishi serves as a legal adviser for the ICRC’s Regional Delegation for the United States and Canada.


Photo credit: Sgt. Christopher Gaylord via Wikimedia Commons