A new framework for responsible employment

This short response engages with Matthew Thornton’s award‑winning paper, Multinational Mercenaries: The Dangers of Private Sector Operational Involvements, and acknowledges his valuable contribution to a topic of increasing contemporary and future significance.[1] My focus, however, is directed toward the implications of contractor use in future armed conflict, examined through the lens of international humanitarian law (IHL) and informed by operational experience.

A substantial body of scholarship, most recently by Natalie McLean[2] and, more broadly, Lindy Heinecken[3], has examined the role of contractors in both Australian and international contexts, typically through political science frameworks. My intention here is to offer observations grounded in my own field of specialisation, IHL, and to consider the practical realities likely to arise in the event of renewed large‑scale conflict.

Much of the prevailing discourse on contractors remains shaped by a persistent Machiavellian trope: that mercenaries, and by association contractors, are inherently unreliable, unethical, or undesirable participants in armed conflict. Thornton’s paper reflects elements of this widely held assumption. That said, from the standpoint of law, operational practice, and empirical experience, this characterisation is not only incorrect, it is increasingly irrelevant. I argue instead for a reframing of contractors as an integrated and indispensable component of any credible Australian military response. Their contribution enhances, rather than diminishes, national capacity to conduct and prevail in armed conflict. Without them, operational success is unlikely.

To illustrate this, consider Thornton’s own scenario: an Australian Defence Force (ADF) unit deployed to support operations in a warlike environment, its numbers depleted and subsequently augmented by contractors both pre‑deployment and in‑theatre. These individuals, civilians with specialised expertise, voluntarily deploy through corporate mechanisms to take a direct part in hostilities.

This is not hypothetical. Australia, the United Kingdom, and particularly the United States have long relied on contractors to supplement military capability. Contractors have occupied back seats in fighter aircraft, operated remotely piloted aircraft, and provided intelligence directly supporting combat operations. These roles constitute direct participation in hostilities. This means their characterisation under IHL changes, from civilian to combatant. This change gives rise to state and command responsibility for training, leading, and preventing war crimes.

States employ contractors in such capacities not out of preference but necessity: they lack sufficient uniformed personnel with the requisite expertise to meet operational demands.

Invoking Machiavelli’s depiction of mercenaries as ‘disunited, ambitious, without discipline’ risks obscuring contemporary realities. In Afghanistan, by 2018, 3,937 contractors supporting the U.S. Government had been killed – more than 30 percent higher than U.S. military fatalities over the same period. One of my own colleagues was killed by an improvised explosive device in Kabul in 2015. Based on my experience as a contractor in Iraq, neither he nor those serving alongside him would ever have contemplated withdrawal from combat, whether due to contractual obligations or personal conviction. Such evidence directly challenges the persistence of this too long‑standing stereotype.

If we accept that contractor participation in armed conflict has been normalised – particularly in Iraq and Afghanistan – Thornton rightly identifies oversight mechanisms of contractors as an area requiring attention. Yet the central issue extends beyond contractual clarity. The more fundamental question, largely avoided by contributing states in recent conflicts, concerns responsibility; and specifically, state responsibility.

If contractors are engaged to provide essential capability, and if their roles amount to direct participation in hostilities, who bears responsibility for their actions under domestic and international law? Legally, the answer is clear: the state that engages them. The practical implications of this remain, at the very least, under‑examined.

Debates about the utility or morality of contractors are, in my view, pointless. The pressing questions relate instead to state responsibility. To facilitate clearer analysis, I propose that when deploying contractors, Australian Defence force adopt the policy framework of RC3: Responsible Contracting of Combatant Capability, which captures the essential dimensions of contractor use in armed conflict:

1. Responsible (who): identifying the entity responsible for enforcing the laws of armed conflict and human rights law, consistent with principles of state and command responsibility.
2. Contracting (how): defining the legal relationship between parties, including rights, obligations, and accountability mechanisms.
3. Combatant (what): recognising the legal status of individuals contracted to take a direct part in hostilities.
4. Capability (when): understanding the operational value contractors provide when capability gaps arise.

This framework matters because ambiguity regarding the status of contractors creates risks for civilians and persons who may be hors de combat. Greater legal and operational clarity enhances transparency and compliance, particularly for states that routinely engage contractors.

Moreover, existing legal frameworks, shaped by political compromises of the 1970s[4], and commentary grounded outside an IHL perspective, often undermine the very policy objectives underpinning the laws of war. These frameworks provide little incentive for all individuals who directly participate in hostilities to adhere to the laws and customs of war. 

The resulting uncertainty exposes military commanders to potential liability for the actions of individuals whose legal status is, at best, ambiguous. In the aftermath of Australia’s experience in Afghanistan, such risks are unacceptable.

Thornton concludes by acknowledging the role of Defence Industry Partners but asserts that ‘we must never need them.’ That position is untenable; it’s too late. We have needed them, we need them now, and we will continue to need them. Recognising this reality, the imperative is not to debate their existence but to ensure robust systems for their management, training, and oversight. In its use of contractors on operations, Australia and the Australian Defence Force have clear domestic and international legal obligations. The RC3 framework offers one pathway to meeting them.

End Notes