(Editor’s Note: The U.S. Department of Defense’s (DoD) Law of War Manual, first published in 2015, sets out the DoD’s authoritative interpretation of international law on matters relating to armed conflict. In recognition of its size, breadth, and the evolving nature of law and conflict, the Manual is also a living document that anticipates needing revisions and updates. In A Living Document, published by Just Security and the Reiss Center on Law and Security, leading scholars and practitioners reflect on how the Manual is keeping pace with its stated purpose and examine specific topics and rules where the Manual may be ripe for clarification or strengthening.)

For States engaged in conflict against a non-State armed group (NSAG), identifying those individuals who may be targeted or detained due to their status as members of the group presents a challenge. While the regular armed forces of a State gain their status from domestic law, there is no equivalent formal basis for identifying members of an NSAG. Instead, States need to look to other factors to determine membership, such as the functions individuals perform on behalf of the group. Yet, those functions are diverse and may not correspond to those performed by the armed forces of a State. Members of NSAGs often integrate into the civilian population and may not wear uniforms or other indicia of membership. And the NSAGs engaged in conflict vary considerably in terms of their size, membership, and operations, and may lack a clear organizational structure.

The United States’ DoD Law of War Manual addresses this challenge by treating members of an NSAG engaged in hostilities against a State as “unprivileged belligerents” (§ As such, the Manual classifies members of an NSAG as “combatants,” meaning that they can be attacked at any time (§ 5.7.2). While this approach arguably differs from that articulated in Additional Protocol I (see Boothby and Heintschel von Heinegg pp. 123-124), it reflects the realities of conflict. Members of an NSAG who participate in the fight are legitimate targets, in the same manner as the armed forces of a State.

To identify who can be targeted or detained based on their status as members of an NSAG, the Manual sets out a broad range of factors that may point toward membership. These include formal criteria, such as the use of rank, or documents identifying the person as a member, as well as indicia based on the individual’s behavior, such as following the group’s directions or traveling along specific clandestine routes (§§, This post reviews the Manual’s approach and seeks to highlight areas of concern, including the risk that the Manual’s guidance casts the net of membership too widely, thereby exposing individuals with only weak links to the NSAG’s military operations to detention or attack.

The DoD Approach Versus the Continuous Combat Function

To determine membership of an NSAG, some allies of the United States take a similar approach to the International Committee of the Red Cross (ICRC) in its Interpretive Guidance on the Notion of Direct Participation in Hostilities (DPH). The ICRC guidance recognizes that individuals with a continuous combat function (CCF) should be targetable at any time, including when they are not participating in hostilities (pp. 71-73). However, the ICRC links this concept to its interpretation of DPH, meaning that individuals only assume a CCF if their “continuous function involves the preparation, execution, or command of acts or operations amounting to direct participation in hostilities” (p. 34). Other individuals working for the group, such as cooks or recruiters, only qualify as members of the NSAG if, in addition to performing those tasks, they also carry out activities amounting to DPH.

 The ICRC’s narrow interpretation of DPH means that many functions performed for an NSAG do not qualify as a CCF, even if they are critical to the group’s combat operations. For instance, under this approach, individuals who manufacture improvised explosive devices for the NSAG or who repeatedly smuggle weapons to the group do not assume a CCF unless they perform these tasks in furtherance of a specific military operation, or they also perform other functions that amount to DPH (pp. 34-35). This means that the individuals concerned are civilians and they are entitled to protection from attack unless and for such time as they take a more direct role in the hostilities.

While the ICRC’s position has the advantage of clarity, it fails to recognize that some tasks that individuals perform for an NSAG are integral to the group’s combat effectiveness, even if there is no direct causal link between those actions and any harm caused. It additionally creates an imbalance with State armed forces. Under the law of armed conflict, all members of a State’s armed forces that are trained to fight are legitimate targets, including those in supporting roles (logistics, intelligence etc.). In contrast, the restrictive notion of CCF means that only those members of an NSAG who continuously perform a combat function are targetable, with all other members of the group having civilian status. In this sense, the ICRC guidance regards non-DPHing members of an NSAG as more akin to civilian contractors who accompany the armed forces, but who are not trained or expected to engage in hostilities.  

 The DoD Manual represents a clear departure from the ICRC guidance and the notion of CCF. It addresses the perceived imbalance with State armed forces by broadening the factors that may indicate membership of an NSAG to include the performance of “tasks on behalf of the group similar to those provided in a combat, combat support, or combat service support role in the armed forces of a State” (§ In addition, rather than following the approach of some States, which characterize members of NSAGs as civilians who have a continuous DPH function, the Manual treats membership of an NSAG as a separate basis upon which individuals may be subject to attack (§ This means that in a non-international armed conflict, members of the non-State party’s armed forces can be targeted based on their status as members of the NSAG at any time the attacking force may choose.

 Criteria for Determining Membership

 The Manual’s approach to determining membership in an NSAG recognizes the critical role that individuals who support an NSAG’s combat operations play towards the group’s success on the battlefield. Concerns arise, however, regarding the breadth of the criteria the Manual lists as potential indications of membership. These include “accessing facilities, such as safehouses . . . used by the group that outsiders would not be permitted to access” or “traveling with members of the group to remote locations or while the group conducts operations” (§ The Manual additionally asserts that individuals who are not members of the NSAG but who participate sufficiently in its activities or substantially support its operations “may be regarded as constructively part of the group, even if they are, in fact, not formal members of the group” (§

 To support this stance, the Manual cites several U.S. domestic cases relating to the authority to detain certain individuals at Guantanamo Bay in connection with the U.S. armed conflict against al Qaeda and “associated forces.” It is questionable, however, whether criteria developed in detention-related habeas cases should be treated as indicators of individuals’ status as legitimate targets. First, the authority to detain is often broader than the authority to use lethal force. Civilians may be detained if they merely pose a threat to security, for example, whereas they are only liable to attack if they DPH or they are members of an NSAG. Second, U.S. courts generally defer to the executive branch on matters of conflict and national security (pp. 378-379). Rather than reasoned decisions based on the law of armed conflict, therefore, the cases the Manual cites largely represent judicial acceptance of the U.S. government’s own interpretation of its domestic legal authority to detain.

 Many of the factors these cases address also seem tailored to the particular circumstances of the U.S.-al-Qaeda conflict and may not have the same probative value in other conflicts. Taken out of context, there is a danger that these decisions and the indicia of membership the Manual draws from them could lead the armed forces to target individuals who are only loosely associated with an NSAG, or who play no role in its military operations (see Fortin pp. 392-395). For instance, while a U.S. court deemed that staying in an al Qaeda guesthouse was “overwhelming” evidence that an individual was part of al Qaeda (§ n. 261), the same conclusion might not be appropriate regarding a guesthouse operated by another NSAG in a different conflict.

 A high degree of caution is therefore necessary when applying the Manual’s guidance. Without this, the DoD approach risks ignoring variations between the operations of different NSAGs. It also seems to overlook the reality that individuals who associate with an NSAG might have minimal links to the group’s combat operations. NSAGs often govern territory, where individuals living under their control might have little option but to use the NSAG’s guesthouses or other facilities, or to travel along clandestine routes that the NSAG uses during its operations, irrespective of membership. In addition, the Manual includes no word of caution that some “mixed” NSAGs have distinct political or social wings that deliver public services to the local population, and whose members retain their civilian status due to their lack of involvement in the group’s military operations.

 Through its expansive guidance regarding membership in an NSAG, the Manual goes beyond simply addressing the disparity with States’ armed forces that results from the notion of CCF. It risks creating a counter imbalance whereby the net of membership is cast so widely that it includes individuals who would not be legitimate targets if they performed similar functions for the armed forces of a State.

 For instance, civilian officials and administrators who work with States’ armed forces retain their civilian status and are protected from attack unless and for such time as they DPH. The same is true of persons authorized to accompany the armed forces, such as private contractors (see § 5.8.2). The Manual, however, indicates that individuals who accompany an NSAG and support its activities should be treated as members of the group (§ There is no caveat to exclude individuals who might only loosely support the NSAG’s combat operations, for example via the provision of food. This broad wording risks treating individuals who carry out a wide range of support functions as members of the group, thereby rendering them subject to detention and attack.

Hostile Intent

 The Manual argues that individuals integrated into an NSAG may be made the object of attack because they “share in their group’s hostile intent” (§ 5.7.3; see also § It remains unclear from the Manual’s text why this language is used, but the aim may have been to assist U.S. armed forces to determine who should fall within the net of membership and who should not. The use of the term in this context is, however, unnecessary, and liable to confuse.

 First, the Manual’s references to hostile intent potentially blur the divide between status-based and conduct-based targeting. In rules of engagement, a determination that individuals exhibit hostile intent normally indicates that they can be targeted based on their conduct at the relevant time, which poses a threat to the force. But here, the Manual links hostile intent with membership of an NSAG, meaning that the individuals concerned are targetable at any time based on their status. This could lead to confusion regarding the basis on which members of an NSAG can be targeted or detained.

 Second, individuals’ motives and intent are irrelevant to determinations whether they can be targeted or detained as members of an NSAG. For instance, NSAGs commonly coerce individuals, including children, to join their ranks. If those individuals act under the group’s command and control, in a role that equates to those undertaken by a State’s armed forces, they are subject to attack or detention irrespective of their intent.

 For the sake of clarity, therefore, references to hostile intent should be removed from these sections of the Manual. If the DoD still wishes to include some form of general guidance to assist the armed forces to determine who should be considered a member, the Manual could refer instead to the individuals’ belligerent conduct, or to their participation in the fight on the NSAG’s behalf.

 Disassociation Threshold

 To disassociate themselves from an NSAG, meaning that they are no longer legitimate targets, the Manual requires that an individual “has unambiguously ceased” to be a member of the group (§ Individuals can demonstrate this by formally renouncing their allegiance to the NSAG, or by “concrete and verifiable facts or persuasive indicia” that they have returned to peaceful pursuits. In addition, the passage of time since the individuals engaged in the NSAG’s activities may indicate that they are no longer part of the group, provided this is “coupled with other indicia of dissociation or renunciation.”
It can prove challenging for armed forces to ascertain whether individuals who were previously members of an NSAG retain that status. Accordingly, it is reasonable for the Manual to require evidence of disassociation before determining that an individual can no longer be targeted or detained. The ICRC’s Interpretive Guidance takes a similar approach, referring in this context to “conclusive behaviour, such as lasting physical distancing from the group and reintegration into civilian life . . .” (p. 72). Nevertheless, the Manual sets a high threshold for disassociation, which could potentially lead to civilian harm. For instance, the requirement for the passage of time to be accompanied by other indications of dissociation suggests that in the absence of such indicia, the armed forces could rely on outdated intelligence to conduct a strike.

The Manual’s guidance regarding disassociation additionally raises practical concerns. In many cases, it may be unrealistic to expect individuals to demonstrate their disassociation from a group “such as by participating in a reconciliation program and swearing an oath of loyalty to the government” (§ It may be wholly impracticable for many former members to take such steps, particularly if they continue to live under the NSAG’s control, such as in an area governed by the NSAG or its political wing. While it might be reasonable to expect a former commander of an NSAG to publicly renounce any allegiance to the group before the opposing armed forces accept that he or she is no longer a member, the same degree of certainty is unlikely to be realistic when considering the disassociation of individuals who have no option but to continue to interact with the NSAG or to live under its control.

 Moreover, the Manual places the onus on the person who belonged to the NSAG “to demonstrate clearly and affirmatively to the opposing forces that he or she will no longer participate in the activities of the group” (§ This wording seems to suggest that if there is intelligence to indicate that individuals may have disassociated from an NSAG, but they have not taken steps to demonstrate this in a clear and affirmative manner, the armed forces can treat the individuals as legitimate targets based on their continued membership of the group. It is questionable how this approach accords with other provisions of the Manual regarding the planning and conduct of attacks (see e.g., §§, 5.5.3). The Manual makes clear that in cases of doubt or incomplete information regarding an individual’s status as a legitimate target, “commanders and other decision-makers [must] make their decisions in good faith based on the information available at the time [and] take feasible precautions to verify that the person or object is a military objective…” To avoid ambiguity, the Manual should make clear that these obligations apply equally when doubt arises regarding an individual’s continued status as a member of an NSAG.

 Conclusion: How the Manual Could be Revised or Improved

 The overall approach the Manual takes to membership in an NSAG is reasonable and does not differ significantly from that taken by many of the United States’ allies. The Manual rightly recognizes that members of an NSAG are targetable at any time based on their status and enhances parity with State armed forces by extending the criteria for membership beyond the restrictive notion of CCF.

 Concerns arise, however, regarding the factors the Manual uses to determine membership. First, the references to hostile intent are unhelpful and should either be removed or replaced with guidance that focuses on the individuals’ belligerent conduct, or their participation in the fight on the NSAG’s behalf. Second, the DoD may wish to re-examine the sources the Manual relies on to support the indicators of membership, to move away from reliance on domestic habeas cases. Third, and most importantly, the criteria given as indicators of membership would benefit from review. Unless employed with extreme caution, these could potentially lead to the targeting and detention of individuals who have only a tenuous connection to the NSAG and its combat operations.

 Given the diversity of NSAGs engaged in conflict, it is not realistic for any law of war manual to devise a complete list of criteria to indicate membership. Every NSAG is different and every decision whether to target or detain a member of an NSAG should be based on an individualized assessment of the facts, including the surrounding context and available intelligence. This requirement is clear from other sections of the Manual, which emphasize the obligations to act in good faith and to take feasible precautions in the planning and conduct of attacks to ensure that the person concerned is a legitimate target (§§, 5.5.3). However, when read in isolation, the guidance relating to membership in an NSAG could lead the U.S. armed forces to target or detain individuals who merely live under the group’s control, or who provide it with some form of support that has tenuous links to the group’s combat operations. In the sections relating to NSAGs, therefore, the Manual should cross-refer back to earlier guidance regarding the planning and conduct of attacks and make clear that these requirements apply to all attacks, including those in which the object of attack is a member of an NSAG.

 Regarding disassociation, the Manual places a heavy burden on the former members of an NSAG to demonstrate that they are no longer part of the group. As with the criteria for membership, the guidance relating to disassociation would benefit from a reminder that this is subject to earlier provisions of the Manual including the presumption of civilian status and the obligation to evaluate the available information in good faith (§ As members of an NSAG are targetable based on their status rather than their conduct, the operational tempo should normally permit U.S. armed forces to allocate the appropriate time and resources to properly verify the status of the individuals concerned prior to any strike (§ 5.5.3).