Symposium on PMSCs: From Contract to Combat – Individual Criminal Liability of PMSC Personnel and Its Integration into Emerging Treaty Frameworks

[Adrián Agenjo is a Clerk at the Constitutional Court of Spain]

The views expressed in this article are the author’s alone and do not represent any institutional affiliation.

The increasing presence of Private Military and Security Companies (PMSCs) in modern conflict- zones has prompted critical questions regarding accountability, particularly when personnel from these entities commit international crimes. Who is held responsible for their actions? This article argues that senior executives and officers within PMSCs can, and should, be held individually liable under international criminal law, specifically through the doctrines of command responsibility and complicity, both of which constitute forms of derivative-imputed liability (see Meloni, p. 621; Jackson, pp. 10-15). Building on this argument, I will examine the implications for the upcoming UN draft treaty on PMSCs.

Extending Command Responsibility to PMSC Superiors

Article 28(1) of the Rome Statute, reflecting customary international law, establishes that a military commander or person effectively acting as a military commander is criminally responsible when their forces commit –or are about to commit crimes– and they “knew or should have known” of the crimes but failed to take all necessary and reasonable measures within their power to prevent, repress or submit the matter to competent authorities. This mode of liability requires three cumulative elements: (1) the superior-subordinate relationship; (2) the superior’s knowledge of the crimes (or “reason to know”); and (3) the superior’s failure to act to prevent or punish the offenses (pp. 221-232).

Regarding the first element, a central issue is whether PMSC personnel qualify as “forces” and to what extent their executives may be considered “persons effectively acting as military commanders”. As private contractors, one might argue they are bound by contractual obligations rather than military hierarchy, challenging the applicability of command responsibility in such cases. However, I contend that formal status is secondary to the existence of effective control. As the ICC Elements of Crimes specifies, anyone who “has effective authority and control” over a group of armed individuals can fall within Article 28’s scope. This functional approach encompasses not only traditional military commanders, but also leaders of non-state armed groups such as rebels, mercenaries, and, by extension, PMSCs personnel.

While PMSCs may not be subjected to the same disciplinary regimes as state armed forces, they frequently operate within hierarchical structures that closely resemble military organizations, particularly when compared to other private sector entities (p. 1026). Despite functioning outside formal military command chains, an expectation of obedience and subordination persists between PMSCs superiors and their personnel (p. 185). A striking example is provided by the case of CACI employees deployed as interrogators at Abu Ghraib Prison. Not only these contractors received instructions from U.S. military personnel, but they were also placed in supervisory roles over lower-ranking soldiers, illustrating the blurred lines of authority and the operational integration of PMSC staff into state-military frameworks (see here and here). In the words of the Bemba decision of the ICC Pre-Trial Chamber, superior responsibility ex article 28(a) may arise when the forces are structured like a conventional army (see para. 456). This convergence of functions and command dynamics has led scholars such as Kuwali (p. 109) and Frulli (pp. 454-466) to argue that PMSCs should be treated, for purposes of accountability, analogously to formal military units.

Thus, in my opinion, the non-state status of PMSCs does not exempt their leaders from criminal responsibility, similarly to non-state militia leaders in the jurisprudence of the International Criminal Tribunals. For example, in the Musema case, the ICTR extended superior responsibility to the director of the Gisovu Tea Factory, where the Trial Chamber found that Musema, in light of his legal and financial control over the factory’s employees, exercised both de jure authority and de facto control over his employees and the resources of the factory (para. 880). Likewise, in the Nahimana case, the ICTR found the accused was a superior and “had  the material capacity to prevent or punish the broadcasting” of genocidal messages by employees of Radio Télévision Libre des Mille Collines, a station over which he exercised control and was widely recognized as its Director (paras. 798-834).

Regarding the failure to act –this is, to prevent, to repress or to refer–, there is no requirement that the superior’s omission must have caused the crime (paras. 396-400). The duty to act emerges ex ante from international law (see Articles 86 and 87 of the Additional Protocol I to the Geneva Conventions), and may be specified and detailed in contractual obligations and domestic guidelines. For instance, the U.S. Department of Defense (DoD) Law of War Program, under DoD Directive 2311.01E, mandates that contractors must adhere to policies preventing violations of the laws of war, including appropriate training and dissemination of relevant regulations. Violations of these obligations should be reported as “suspected violations of the law of war.” However, it must be emphasized that domestic law, and even less private sources of law such as a contract, cannot reduce the scope of the duty to act (for a wider account of the superior’s specific duties, see Garrocho).

In terms of mens rea, once the superior-military status of senior PMSCs personnel is established, constructive knowledge and negligence would be sufficient (according to the wording of the Rome Statute, “either knew or, owing to the circumstances at the time, should have known”). This standard is more lenient than the subjective element required for civilian superior responsibility, which mandates that the superior either knew or consciously disregarded information that clearly indicated the commission of a crime. Although some scholars (p. 123) may suggest otherwise, I find no compelling reasons to assert that PMSCs have a reduced duty to remain informed.

Building on the above, it seems that Article 28(2) of the Rome Statute, governing civilian superior responsibility, fails to adequately capture the degree of wrongdoing and culpability attributable to senior personnel of PMSCs. Article 28(2) imposes is designed for civilian leaders who may lack formal authority, explicit legal duties, or military training, and such a framework appears ill-suited to the reality of PMSC structures. As stated, senior PMSC operatives often operate within hierarchical chains of command, enforce internal discipline, and possess clear obligations derived from regulatory regimes and international law. In fact, the rationale behind applying the more demanding subjective standard of knowledge under Article 28(2) rests on the civilian superior’s typically ambiguous legal duties and limited oversight powers —an assumption that does not hold true for PMSC leadership (p. 124). Where there is no clear legal duty of supervision that the civilian superior has breached, it is the presence of moral culpability that justifies punishment. But where, as with many senior PMSCs actors, both de jure and de facto control is demonstrable, and the operational conduct reveals familiarity with armed conflict environments and is bound by humanitarian law obligations, the stricter standards of Article 28(2) are both normatively inadequate and empirically inaccurate.

The Possibility of Complicity

Complicity provides an alternative pathway for holding accountable PMSCs personnel who contribute to the commission of international crimes. In terms of actus reus, the accomplice’s contribution must bear a causal link to the principal offense and have had a significant or substantial effect on its commission (pp. 216-217).

PMSCs may contribute to the commission in various causal and significant ways, including:

1. Providing advice or training to state armed forces, which could lead to PMSCs personnel inducing, encouraging, or even ordering members of the military to commit international crimes. In such cases, individual criminal liability may be incurred by PMSCs employees, even if they are not formally part of the armed forces (p. 144).
2. Supplying military forces with technical assistance, weapons, or other resources that facilitate the commission of international crimes (p. 1023).
3. Engaging in operations, such as identifying civilian targets for attack or acting as prison guards in facilities where prisoners are tortured (p. 1024).

Regarding mens rea, customary international law requires that an individual must have knowledge that their actions will contribute to the commission of a crime. However, Article 25(3)(c) of the Rome Statute states that the contribution must be made “for the purpose of facilitating the commission of such crime.” This provision introduces an additional intent requirement (pp. 21-30).

Certainly, this presents challenges in proving the crime. However, the concept of purpose could be interpreted as knowledge (“knowledge-based approach”), meaning that if the accused has knowledge of the criminal act, it can be inferred that the accused also has the intent to facilitate it (see, in relationship with genocide, Agenjo). This has been the approach taken by the ICTY in Popović (para. 1500). Alternatively, there are other interpretations that sustain that the intent requirement should be understood as applying to the contribution made by the individual, rather than to the principal crime itself (p. 558).

As knowledge and intent can be inferred from the circumstances, it is essential to assess the factors that may be relevant for such inferences, particularly in the context of corporate activities. Specific evidentiary challenges arise when liability is claimed against corporations involved in commercial transactions, such as supplying goods or services to perpetrators that have multiple uses —both harmful and benign (p. 269).

In connection with the above, in certain cases, the contributions made by PMSCs could potentially be considered as “neutral conduct”—actions that, on their own, do not inherently support or facilitate criminal activity. However, for a conduct to be deemed neutral, it must fulfill three essential characteristics: (1) it must be inherently permitted, (2) it must align with standardized norms and roles of action within the specific context, and (3) it must be part of regular, everyday activities (pp. 24-25). For instance, providing training or equipment to armed forces may qualify as a neutral act if such support is intended for lawful, non-criminal purposes, such as improving operational efficiency or enhancing defense capabilities.

However, the context in which these actions take place and their potential dual-use nature must be carefully considered. While PMSCs may sometimes operate in non-conflict zones or under mandates limited to ostensibly non-violent purposes —such as humanitarian assistance or defensive training —such contexts do not automatically render their conduct neutral. Even so, recent controversies —such as the involvement of Global Humanitarian Foundation (GHF) in Gaza— suggest that, even in humanitarian settings, PMSC activities may raise serious concerns regarding potential complicity in international crimes. Thus, although neutrality may still be arguable in certain exceptional cases, these cases are the exception rather than the rule. In any case, in the context of armed conflicts or fragile states, where the risk of misuse is heightened, the presumption of neutrality becomes considerably less convincing.

Implications for the OEIGWEG Draft on PMSCs

The international community is already moving to regulate PMSCs more tightly. The UN Human Rights Council’s Open-Ended Intergovernmental Working Group (OEIGWG) has been developing a draft instrument to protect human rights and ensure accountability for PMSCs operations. The draft instrument includes provisions for regulatory mechanisms —such as registration, licensing of contracts, on-site monitoring, and the investigation of abuses— which could prove valuable in any criminal or civil process aimed at ensuring accountability for violations committed by PMSCs personnel. However, the draft instrument remains largely focused on state obligations and corporate due diligence, placing relatively limited emphasis on the role and responsibility of individual PMSCs personnel.

Articles 4, 5, 6, 12, 13 and 16 of the draft instrument explicitly require States Parties to ensure that PMSCs personnel adhere to international human rights and humanitarian law, and to undertake prompt investigations and prosecutions of violations of such rules. While these provisions are welcome, they reflect a predominantly top-down regulatory model that places the burden of enforcement on the state and corporate structures. This model could be significantly strengthened by incorporating a bottom-up deterrence strategy grounded in individual criminal liability.

In light of the current limitations of the OEIGWG draft, there are, in my view, several concrete ways in which criminal accountability could be meaningfully incorporated into the framework:

1. Incorporating direct and specific references to international criminal law norms, further clarifying that contractual or corporate affiliation does not shield individuals from personal criminal liability.
2. Codifying obligations of prevention and control for corporate superiors: drawing on the doctrine of command responsibility, the instrument could establish that individuals in managerial or supervisory roles within PMSCs bear a duty to prevent or repress international crimes committed by their subordinates, with failure to fulfill this duty giving rise to individual criminal responsibility.
3. Mandating state cooperation with international prosecutions: the instrument could require states to cooperate with international criminal tribunals or hybrid mechanisms for the investigation and prosecution of PMSC-related crimes.
4. Embedding triggers for criminal investigation: the instrument could impose a duty on contracting states to initiate or facilitate criminal investigations, including through referrals to international bodies or under universal jurisdiction principles.
5. Establishing a monitoring and reporting mechanism: the instrument  could empower an independent body to collect and transmit evidence of individual criminal responsibility to national or international prosecutorial authorities.

In fact, individual criminal liability could serve as a foundation for establishing corporate criminal liability for PMSCs (see the proposal of Collins), which would at the same time strengthen the corporate-regulation approach. As Van Sliedregt aptly notes, the future of international criminal justice is corporate —a future that must be built upon individual liability. Accountability for PMSCs must go beyond corporate compliance and reach the individuals who command, encourage, or enable international crimes. By embedding doctrines like command responsibility and complicity into the regulatory framework, the treaty can finally match the evolving realities of warfare with the legal tools needed to confront impunity.