Ben Roberts-Smith War Crimes Trial: Is the Retroactive Law Legal?

Introduction

The Ben Roberts-Smith war crimes prosecution has raised a difficult legal question: can Australia retrospectively amend its criminal legislation and apply the change to alleged offenses committed more than a decade earlier? In October 2024, Parliament broadened the Commonwealth Criminal Code's definition of hors de combat, a term describing persons who are no longer participating in hostilities and are protected against attack. The amendment was expressly applied to conduct dating back to September 26, 2002. Although retrospective criminal legislation is not automatically unconstitutional in Australia, its application must be examined against the principle of legality and the criminal law governing conduct when it occurred.

On April 7, 2026, Australian authorities charged Roberts-Smith, a former Special Air Service Regiment corporal and Victoria Cross recipient, with five counts of war-crime murder concerning alleged killings in Afghanistan between 2009 and 2012. He denies committing war crimes. His October 2026 interview with broadcaster Ben Fordham brought renewed public attention to the allegations and his defense of his military conduct. The prosecution remains at a preliminary stage, and no criminal court has determined his guilt (CDPP, 2026).

The legal controversy concerns the relationship between international humanitarian law and Australian criminal legislation. International law already prohibited murdering detained persons and others who had ceased participating in hostilities during the Afghanistan conflict. Yet the existence of that prohibition does not automatically establish that Parliament may retrospectively alter every statutory condition for criminal conviction. The original Australian definition of hors de combat was narrower than the internationally recognized formulation, creating a question about the legal consequences of its retrospective correction.

The position is complicated by amendments enacted in 2016, which changed aspects of Australia's war-crimes legislation but applied certain changes only to subsequent conduct. The charges against Roberts-Smith concern earlier events. Determining which provisions governed those events, and how the 2024 definition interacts with them, is essential to understanding whether retrospective criminal liability presents a genuine legal problem in this prosecution.

1. Ben Roberts-Smith War Crimes Charges in 2026

Ben Roberts-Smith served in the Australian Army's Special Air Service Regiment and received the Victoria Cross for Australia for his actions during combat in Afghanistan. His military service became the subject of extensive controversy following allegations of unlawful killings during Australian special forces operations.

In 2016, the Inspector-General of the Australian Defence Force appointed Major General Justice Paul Brereton to investigate allegations of misconduct in Afghanistan. The resulting Afghanistan Inquiry, publicly released in November 2020, identified credible information concerning 23 incidents involving the alleged unlawful killing of 39 people by, or involving, 25 Australian special forces personnel. The inquiry also identified the alleged cruel treatment of two individuals and serious failures in military culture and oversight (IGADF, 2020).

Those findings did not constitute criminal convictions. They provided grounds for further investigation and institutional reform. The Office of the Special Investigator and the Australian Federal Police subsequently investigated possible criminal offenses.

Their work requires distinguishing misconduct, violations of international humanitarian law, and conduct satisfying the elements of a specific criminal offense. Under the rules governing war crimes and individual criminal responsibility, criminal liability must be established against each accused person through the applicable law and admissible evidence.

1.1 Five Murder Charges and the Alleged Killings

On April 7, 2026, the Australian Federal Police and the Office of the Special Investigator arrested Roberts-Smith and charged him with five offenses under section 268.70(1) of the Commonwealth Criminal Code. The charges concern the deaths of five Afghan nationals allegedly killed during Australian military operations between April 2009 and October 2012. Each offense carries a maximum penalty of life imprisonment. The prosecution is brought in the name of the Commonwealth Attorney-General under section 268.121(2) (CDPP, 2026).

Two charges relate to April 12, 2009. One alleges direct commission of war-crime murder; the other alleges aiding, abetting, counseling, or procuring a separate murder. A third charge concerns September 11, 2012, and alleges participation through aiding, abetting, counseling, or procuring. The remaining two charges concern October 20, 2012, with one alleging accessorial responsibility and the other joint commission.

The incidents have been associated in public reporting with military operations at Kakarak, Darwan, and Syahchow in Uruzgan province. The Commonwealth Director of Public Prosecutions states that the alleged victims were not taking an active part in hostilities. The factual circumstances of their deaths, including whether they were detained or otherwise defenseless, remain issues for criminal adjudication.

The different modes of liability are legally significant. Section 11.2 of the Criminal Code governs complicity and common purpose, including aiding, abetting, counseling, and procuring an offense. Section 11.2A governs joint commission under an arrangement or understanding involving the commission of an offense. Each provision has requirements beyond the mere existence of a relationship between the accused and another alleged perpetrator.

The prosecution must establish the applicable form of responsibility for each charge. It cannot rely solely on Roberts-Smith's military rank, his presence during an operation, or allegations that another soldier committed an unlawful killing. The charged conduct, required mental elements, and connection with the underlying offense must be proved according to the relevant statutory provisions.

1.2 The Defamation Case and Its Criminal Law Limits

The criminal prosecution followed years of litigation concerning allegations published by Australian newspapers. Roberts-Smith brought defamation proceedings against media organizations and journalists after reports accused him of serious misconduct during his Afghanistan deployments. On June 1, 2023, Justice Anthony Besanko dismissed his claims in Roberts-Smith v Fairfax Media Publications Pty Ltd (No 41) [2023] FCA 555.

The Federal Court found that the media defendants had established substantial truth concerning important allegations, including unlawful killings. Those findings were reached under the civil standard of proof, the balance of probabilities. Because the allegations were exceptionally serious, the court assessed the evidence according to section 140 of the Evidence Act 1995 and the considerations associated with Briginshaw v Briginshaw (1938) 60 CLR 336.

The civil standard differs from the criminal requirement of proof beyond reasonable doubt. Section 140 does not establish a separate intermediate standard of proof, but it requires the court to consider matters including the nature of the cause of action, the subject matter, and the gravity of the allegations when determining whether it is reasonably satisfied that a fact has been proved.

Roberts-Smith appealed the judgment. On May 16, 2025, the Full Court of the Federal Court dismissed his substantive appeal in Roberts-Smith v Fairfax Media Publications Pty Ltd [2025] FCAFC 67. The High Court subsequently refused special leave in related proceedings on September 4, 2025, including Roberts-Smith v Fairfax Media Publications Pty Ltd [2025] HCADisp 212.

The adverse civil findings remain distinct from any criminal determination. The prosecution must independently establish the elements of the offenses beyond reasonable doubt. Evidence considered during the defamation proceedings does not automatically become conclusive in the criminal case, and its admissibility and use remain subject to the applicable rules of criminal procedure.

2. Australia's 2024 Retrospective War Crimes Amendment

The legislative controversy concerns Schedule 7 of the Crimes and Other Legislation Amendment (Omnibus No. 1) Act 2024, which received royal assent on October 24, 2024. The legislation replaced the definition of hors de combat in the Dictionary to the Commonwealth Criminal Code. Parliament expressly applied the revised definition to conduct occurring on or after September 26, 2002 (Commonwealth of Australia, 2024, Schedule 7).

The expression hors de combat, meaning outside the fight, identifies persons who must no longer be attacked because circumstances such as surrender, capture, or incapacity have removed them from active hostilities. The concept forms part of the protection afforded to individuals under the Geneva Conventions and the law governing war victims.

The amendment addressed a discrepancy between the Australian definition and the formulation in Article 41 of Additional Protocol I to the Geneva Conventions. Parliament had originally adopted a more restrictive definition that treated certain requirements as cumulative. The 2024 legislation substituted a formulation that recognizes alternative circumstances in which a person may qualify as hors de combat.

2.1 The Original Hors de Combat Definition

Australia introduced Division 268 of the Criminal Code through the International Criminal Court (Consequential Amendments) Act 2002. The legislation established domestic offenses concerning genocide, crimes against humanity, and war crimes, reflecting Australia's implementation of the Rome Statute framework. The relevant provisions commenced on September 26, 2002.

The original definition required that a person be in the power of an adverse party and also either clearly express an intention to surrender or become unconscious or otherwise incapacitated by wounds or sickness so as to be incapable of self-defense. The person also had to abstain from hostile acts and attempts to escape (Criminal Code Act 1995, Dictionary, pre-2024 wording).

This formulation was narrower than Article 41(2) of Additional Protocol I. Under that provision, a person may be considered hors de combat when in the power of an adverse party, when clearly expressing an intention to surrender, or when incapacitated by wounds or sickness. These are alternative qualifying circumstances, subject to the requirement that the person abstain from hostile acts and attempts to escape (Additional Protocol I, 1977, art. 41).

The difference is particularly apparent in cases involving captured persons. Under the original Australian definition, detention alone did not necessarily satisfy the statutory requirements because the person also needed to meet the additional condition concerning surrender or incapacity. The international formulation recognizes adverse-party control as an independent ground for protection.

This discrepancy did not mean that international humanitarian law permitted the killing of detainees who failed to satisfy Australia's original definition. Common Article 3 independently prohibited murdering persons who had ceased participating in hostilities through detention or other circumstances. The legal difficulty concerns whether the narrower domestic wording affected the conditions for conviction under particular Commonwealth offenses.

2.2 The 2024 Definition and Its Retrospective Application

Schedule 7 of the 2024 Act substituted a definition under which three circumstances operate alternatively. A person may be hors de combat by being in the power of an adverse party, by clearly expressing an intention to surrender, or by becoming unconscious or otherwise incapacitated through wounds or sickness so as to be incapable of self-defense. The requirement to abstain from hostile acts and attempts to escape remains applicable.

The amendment closely follows Article 41(2) of Additional Protocol I and corresponds with the established customary prohibition against attacking persons hors de combat. Its wording is materially broader than the previous statutory definition because adverse-party control no longer needs to be combined with surrender or incapacity.

The legislation establishes two different commencement arrangements. Schedule 7, Part 1, which replaces the definition, is deemed to have commenced on September 26, 2002. Part 2 commenced on October 25, 2024. Item 2 expressly applies the substituted definition to conduct occurring on or after September 26, 2002, and to qualifying proceedings commenced from that date that had not been finally determined before Part 2 commenced.

The retrospective reach is consequently explicit. It extends to the period during which Roberts-Smith allegedly committed the charged offenses, even though the criminal proceedings began after the amendment was enacted.

The remaining question concerns legal effect. Replacing a definition does not necessarily create a new offense or alter every element of an existing offense. Its consequences depend on how the defined term operates within the particular criminal provision. That distinction is central because the five charges concern section 268.70 rather than an offense expressly requiring the prosecution to establish hors de combat status as its sole protected-person category.

3. Which Criminal Code Applied to the Alleged Killings?

The prosecution relies on section 268.70(1), which concerns war-crime murder committed during a non-international armed conflict. It does not rely on section 268.40, which separately criminalizes killing or injuring persons hors de combat during an international armed conflict. The two offenses employ different statutory formulations and must not be treated as interchangeable (Criminal Code Act 1995, ss. 268.40 and 268.70).

Section 268.40 expressly includes the victim's status as hors de combat among the elements of the offense. Section 268.70 is structured around the protection of persons not taking an active part in hostilities. The latter formulation is broader in its wording, although the precise meaning and operation of its protected-person category remain questions of statutory interpretation.

The historical version of section 268.70 is particularly important because Parliament amended it in December 2016. Some changes applied only prospectively, while others expressly applied to earlier conduct. The statutory provisions governing alleged acts from 2009 to 2012 cannot be determined simply by reading the consolidated Criminal Code as it appears in 2026.

3.1 Section 268.70 as It Stood in 2009–2012

During the period of the alleged offenses, section 268.70(1) criminalized causing the death of one or more persons who were not taking an active part in hostilities. The perpetrator was required to know of, or be reckless as to, the factual circumstances establishing that the victims were not actively participating. The conduct also had to occur in the context of, and be associated with, an armed conflict that was not international in character.

The offense carried a maximum penalty of life imprisonment. Subsection 268.70(2) clarified that persons not taking an active part in hostilities included persons hors de combat and civilians, medical personnel, or religious personnel who were not actively participating (Criminal Code Act 1995, s. 268.70, pre-2016 wording).

The phrase used in subsection (2) is significant. It was introduced as a clarification of the expression in subsection (1), rather than as an exhaustive definition of every person protected by the offense. This provides a textual basis for considering whether a victim could satisfy the broader non-participation requirement without the prosecution relying exclusively on the definition of hors de combat.

The mental elements require equally careful treatment. Paragraph 268.70(1)(c) expressly addresses the accused's knowledge or recklessness concerning the factual circumstances establishing the victim's status. It does not, by itself, state every fault element relevant to the offense.

Under section 5.6 of the Criminal Code, where legislation does not specify a fault element for a physical element consisting only of conduct, intention is the default. Where the physical element consists of a circumstance or result, recklessness is the default. Section 5.4(4) provides that a recklessness requirement may also be satisfied by proof of intention or knowledge.

The requirement that the perpetrator cause death must accordingly be read with the Code's general fault-element provisions, while the express mental element concerning protected status retains its separate operation. The CDPP describes the prosecution's allegations as involving intentionally caused deaths. The different modes of participation under sections 11.2 and 11.2A impose further requirements that must be established for the relevant charges (CDPP, 2026).

3.2 The 2016 Amendments and Their Temporal Limits

The Criminal Code Amendment (War Crimes) Act 2016 altered several provisions concerning offenses committed during non-international armed conflicts. Part 1 of Schedule 1 introduced express references to membership in organized armed groups. Section 268.70(1) was amended to require that the victim was neither taking an active part in hostilities nor a member of an organized armed group.

The legislation also inserted subsection 268.70(3), providing that members of organized armed groups who are hors de combat are excluded from the organized-armed-group category for the purposes of that section. The amendment reflected the distinction between active members of organized armed groups and individuals who are no longer participating in hostilities because they have become protected through surrender, detention, or incapacity.

The temporal operation of these changes is expressly limited. Schedule 1, item 13, provides that amendments made by Part 1 apply to conduct occurring on or after their commencement on December 8, 2016. They do not automatically govern the alleged Roberts-Smith offenses from 2009 to 2012 (Commonwealth of Australia, 2016, Schedule 1, item 13).

Other amendments enacted in 2016 had a different temporal reach. Part 2 inserted subsection 268.70(1A), concerning specified incidental deaths during attacks on military objectives. The provision addresses circumstances in which the perpetrator did not expect excessive incidental civilian harm and that expectation was reasonable under the statutory conditions.

Schedule 1, item 14, expressly applies the amendments made by Parts 2 and 3 to conduct occurring before, on, or after commencement. Subsection 268.70(1A) may consequently have temporal application to earlier conduct, although its subject concerns incidental harm associated with attacks on military objectives rather than the intentional killing of persons under control alleged in the present prosecution.

These distinct commencement rules prevent the 2016 Act from being treated as a single retrospective or prospective measure. The applicable legal provisions must be identified amendment by amendment. In particular, subsection 268.70(3) cannot simply be imported into the offense as it applied to events allegedly occurring several years before December 2016.

3.3 Does the Amendment Change Who Is Protected?

The central statutory question concerns the relationship between the general protected-person requirement in section 268.70(1) and the inclusive clarification in subsection (2). The former concerns persons not taking an active part in hostilities. The latter expressly includes persons hors de combat within that category.

The 2024 amendment broadens the statutory definition of hors de combat. Its incorporation through subsection (2) could affect how the provision identifies particular protected persons. Yet subsection (2) does not expressly state that every person covered by subsection (1) must satisfy that definition.

This distinction supports an interpretation under which the prosecution could establish that a victim was not taking an active part in hostilities through the facts of the case, independently of proving every component of the defined term. It remains an interpretation of the statutory text, however, rather than an established judicial determination concerning Roberts-Smith's charges.

The prohibition on murdering detainees under international humanitarian law provides relevant legal context. A person detained by an adverse party is protected against deliberate killing even if that person previously participated in hostilities. Common Article 3 recognizes detention as a circumstance through which an individual may be placed hors de combat.

The existence of that international protection does not dispense with the domestic elements of section 268.70. A criminal court must still determine whether the alleged victim satisfied the statutory requirements applicable to the offense, whether the accused possessed the necessary mental state, and whether the remaining elements have been established.

The retrospective amendment may become especially significant if the prosecution relies upon the revised definition to establish protected status in circumstances not clearly covered by the earlier statutory wording. If the historical offense independently covers the alleged victim, the amendment may have a more limited practical effect. Which interpretation governs, and whether the distinction affects any particular charge, remain questions for the criminal proceedings.

4. Is the Retrospective Amendment Legal?

Retrospective legislation is not automatically unconstitutional in Australia. The Commonwealth Parliament may enact laws affecting past conduct where it possesses constitutional authority and does not infringe another constitutional limitation. Criminal retrospectivity nevertheless raises legal concerns about certainty, foreseeability, and the protection against conviction for conduct that was not criminal when committed.

The inquiry involves three related but distinct bodies of law. International humanitarian law establishes the substantive prohibitions governing conduct during armed conflict. International human rights law protects individuals against impermissible retrospective criminal punishment. Australian constitutional and criminal law determine Parliament's legislative authority and the statutory requirements for conviction.

The distinction between an established international prohibition and a later domestic statutory amendment is especially important. Conduct may have been criminal under international law before Parliament corrected its domestic formulation. That history supports the argument for retrospective application, but it does not resolve how the amendment affects the elements of the Australian offense.

4.1 International Law Prohibiting the Alleged Killings

The prohibition on murdering persons who have ceased participating in hostilities was established long before the alleged offenses. Common Article 3 of the four Geneva Conventions applies during non-international armed conflicts and requires humane treatment of persons taking no active part in hostilities, including individuals who have laid down their arms or become hors de combat through sickness, wounds, detention, or another cause.

Common Article 3 expressly prohibits violence to life and person, particularly murder, against those protected individuals. The rule applies regardless of whether the detainee previously participated in fighting or belonged to an opposing armed group (Geneva Conventions, 1949, common art. 3).

Article 41 of Additional Protocol I also prohibits attacks against persons recognized, or who should be recognized, as hors de combat. Although that treaty provision concerns international armed conflicts, the prohibition on attacking persons hors de combat is recognized as customary international humanitarian law applicable in both international and non-international armed conflicts (ICRC, 2005, Rule 47).

The customary rule recognizes protection arising from adverse-party control, qualifying incapacity, or an expressed intention to surrender, provided the person abstains from hostile acts and attempts to escape. Its application is not conditional upon the narrower cumulative requirements formerly contained in Australia's Criminal Code Dictionary.

International criminal law provides a separate basis for individual responsibility. Article 8(2)(c)(i) of the Rome Statute of the International Criminal Court criminalizes murder of persons taking no active part in hostilities during a non-international armed conflict. The Rome Statute entered into force on July 1, 2002, before the alleged Roberts-Smith offenses.

The Rome Statute also recognizes criminal legality. Articles 22 and 24 address the prohibition on retroactive criminal liability within the International Criminal Court's legal system. Those provisions do not automatically govern the validity of Australian legislation, but they illustrate the requirement that criminal responsibility be grounded in applicable law.

The established prohibition on murdering detainees strengthens the argument that the 2024 amendment concerned conduct already criminal under international law. It does not establish that every retrospective change to the domestic definition is immaterial. The legal conditions governing conviction under section 268.70 must still be identified and applied.

4.2 Article 15 ICCPR and Retroactive Criminal Liability

Article 15 of the International Covenant on Civil and Political Rights establishes the principal international human rights protection against retrospective criminal punishment. Article 15(1) prohibits conviction for conduct that did not constitute a criminal offense under national or international law when committed. It also prohibits the imposition of a heavier penalty than the one applicable at the time and requires the benefit of a lighter penalty subsequently provided by law.

Article 15(2) preserves the possibility of trying and punishing conduct that was criminal when committed according to the general principles of law recognized by the community of nations. The provision is relevant to historical international crimes that may have been prohibited before their later incorporation into particular domestic criminal statutes.

Australia's Attorney-General's Department recognizes that retrospective expansion of an existing criminal offense may engage Article 15. Its guidance on the prohibition of retrospective criminal laws distinguishes amendments that expand criminal liability from procedural changes that do not alter the substantive offense or applicable punishment (Attorney-General's Department, Prohibition on Retrospective Criminal Laws).

In the Roberts-Smith prosecution, the distinction concerns whether the 2024 amendment retrospectively changes the conditions for establishing guilt or gives fuller statutory expression to conduct already criminal under the applicable law. The answer cannot be determined solely by identifying the international prohibition. It requires consideration of the historical Commonwealth offense and the legal effect of the substituted definition.

The government's position relies on the longstanding prohibition against murdering persons who have surrendered, been detained, or otherwise ceased participating in hostilities. An opposing interpretation emphasizes the difference between an international prohibition and the narrower conditions expressed in Australia's earlier criminal legislation.

Foreseeability is relevant to that distinction. The principle of legality requires sufficient certainty concerning the conduct for which criminal responsibility may arise. A retrospective amendment that clarifies an existing prohibition may present a different problem from one that supplies a materially new basis for conviction.

Article 15 is non-derogable under Article 4(2) of the ICCPR. Its protection cannot be suspended through the Covenant's emergency derogation provisions, although Article 15(2) remains part of the substantive rule itself.

Australia's international obligations must also be distinguished from their domestic enforceability. The ICCPR has not been incorporated wholesale into Australian law. A breach of an unincorporated treaty obligation does not automatically invalidate Commonwealth legislation, although international obligations may inform statutory interpretation where the applicable domestic rules permit.

The relationship between criminal legality and international human rights law consequently requires attention to both legal systems. Article 15 supplies a binding international obligation for Australia, while constitutional validity and the elements of the offense remain questions governed by Australian law.

4.3 Australian Constitutional Law and Polyukhovich

The Australian Constitution contains no general express prohibition on retrospective criminal legislation comparable to the Ex Post Facto Clauses of the United States Constitution. The Commonwealth Parliament may enact retrospective legislation where it acts within its constitutional powers and respects applicable constitutional limitations.

The common law has long recognized a presumption against retrospectivity, particularly where legislation adversely affects existing rights or imposes new liabilities. That presumption is a principle of statutory interpretation. It cannot override clear legislative language expressly requiring retrospective application (ALRC, 2015).

The leading constitutional authority is Polyukhovich v Commonwealth (1991) 172 CLR 501. The High Court considered amendments to the War Crimes Act 1945 that permitted prosecution of specified offenses allegedly committed during the Second World War. The legislation operated retrospectively, applying criminal consequences to conduct committed decades earlier.

The Court upheld the validity of the challenged legislation, although the justices differed in their reasoning. The decision established that retrospective criminal legislation is not necessarily unconstitutional merely because the relevant conduct occurred before its enactment.

Justice Dawson considered the distinctive circumstances of retrospective war-crimes legislation, including the fact that conduct recognized as seriously wrongful under established legal standards could have been criminal had it occurred in Australia. Other members of the Court addressed the constitutional scope of the external affairs power and the relationship between retrospective legislation and judicial power.

The separation of judicial power under Chapter III remains an important limitation. Parliament may prescribe legal rules applicable to historical conduct, but it cannot itself exercise the judicial function of determining an individual's criminal guilt. Legislation that effectively declares a particular person guilty or dictates the outcome of a criminal proceeding raises constitutional questions different from those arising through retrospectivity alone (ALRC, 2015).

The result in Polyukhovich does not resolve the present controversy. The decision concerned different legislation and historical circumstances. Its significance lies in establishing the constitutional possibility of retrospective criminal enactments, subject to the relevant limitations.

The 2024 amendment also differs from the legislation considered in Polyukhovich because it changes a statutory definition incorporated into existing criminal offenses. Its constitutionality and operation depend upon the actual legal effect of that substitution.

Parliament's intention to give the amendment retrospective effect is explicit. Schedule 7 identifies September 26, 2002, as the deemed commencement date. The remaining interpretive issue is how that substituted definition affects the applicable elements of section 268.70, particularly for conduct predating the 2016 amendments.

5. The Government's Position and the 2026 Legislative Dispute

The Australian government justified the 2024 amendment as a correction of the Criminal Code's original definition of hors de combat. During parliamentary consideration, it explained that the earlier wording did not accurately reflect the intended operation of Australia's war-crimes legislation or the definition recognized under international humanitarian law.

The government maintained that the substituted wording brought Australian law into line with established international obligations. Parliamentary explanatory material also referred to Australian Defence Force training and operational practice based on the international humanitarian law definition, rather than the narrower statutory formulation (Commonwealth of Australia, 2024, Supplementary Explanatory Memorandum).

That justification rests on the existence of a prohibition that preceded the amendment. If the underlying conduct was already criminal under international law, retrospectively correcting the domestic wording may be defended as the restoration of the protection Parliament originally intended to implement.

The Senate Standing Committee for the Scrutiny of Bills nevertheless expressed concerns about the retrospective effect. In Scrutiny Digest 12/24, the committee acknowledged the importance of aligning Australian law with international obligations but observed that the amendment appeared to change the operation of existing domestic law.

The committee identified the possibility that retrospective application could adversely affect individuals by exposing them to liability for a criminal offense that they might not otherwise have committed under the previous statutory formulation. It also noted the potential application to pending proceedings. These concerns were raised notwithstanding the government's explanation that the amendment corrected an earlier drafting error (Senate Standing Committee for the Scrutiny of Bills, 2024, paras. 1.66–1.69).

The committee did not determine that the amendment was unconstitutional or inconsistent with Article 15 of the ICCPR. Its assessment concerned the appropriateness and possible legal consequences of retrospective legislation. Parliamentary scrutiny identifies possible risks without constituting a judicial determination of statutory validity.

The controversy continued in 2026. During Senate consideration of the Statute Update Bill 2026 on September 10, One Nation introduced amendment sheet 4121, proposing to restore the original narrower definition of hors de combat. The proposed wording would again require adverse-party control together with an additional condition concerning surrender or incapacity.

The proposal also contained provisions applying the restored definition retrospectively to conduct occurring from September 26, 2002, and to qualifying pending proceedings. It would, if enacted in that form, create another retrospective alteration of the statutory definition, this time reversing the substantive change made in 2024.

On September 10, 2026, the Senate approved One Nation's amendment restoring the original narrower definition of hors de combat and passed the amended Statute Update Bill 2026. The House of Representatives received the Senate's amendments on September 14 and voted to defer their consideration to a subsequent sitting. As of October 22, 2026, the proposed reversal had not become law, and the broader definition introduced in 2024 remained operative.

The opposing positions reveal a genuine legal disagreement. The government's justification emphasizes that the international prohibition on killing protected persons existed before the alleged conduct. Critics emphasize the requirement that criminal liability be determined according to sufficiently established legal rules and the possible consequences of retrospectively changing the statutory wording.

The significance of that disagreement depends on section 268.70. If the substituted definition changes a legally necessary basis for conviction, the retrospective issue becomes substantial. If the historical offense independently covered the alleged conduct, the amendment may have a more limited role. The competing parliamentary positions do not establish which interpretation the criminal court will adopt.

6. What the Amendment Could Mean for Roberts-Smith

The practical effect of the 2024 amendment depends upon the elements of the five charges and the evidence concerning the alleged victims. The prosecution alleges that Roberts-Smith caused or participated in the deaths of persons not taking an active part in hostilities. The relevant offense is section 268.70, which already contained that general protected-status requirement during 2009–2012 (CDPP, 2026).

The statutory definition of hors de combat is relevant because subsection 268.70(2) expressly includes such persons within the category of individuals not taking an active part in hostilities. Yet the inclusive language does not expressly make the defined term the exclusive basis of protection.

The criminal court may consequently need to determine whether the allegations can satisfy the historical offense independently of the 2024 definition or whether the prosecution's case requires reliance on the substituted wording. No verified ruling has established that the retrospective amendment is indispensable to any of the five charges.

6.1 The Victims' Status and the Elements of Murder

Two charges concern alleged killings on April 12, 2009, during operations associated with Kakarak. The prosecution alleges direct commission of one murder and participation in another through aiding, abetting, counseling, or procuring. The criminal court must determine the factual circumstances of each death and the accused's alleged involvement.

If the prosecution establishes that an alleged victim was detained and no longer participating in hostilities, those circumstances would be directly relevant to the historical protected-person requirement. Common Article 3 prohibits murdering persons placed hors de combat through detention, while section 268.70 requires proof of the domestic offense's applicable elements.

The September 11, 2012 charge concerns an alleged killing associated with Darwan. The prosecution relies on section 11.2, requiring proof of the relevant form of participation in the underlying offense. The accused's alleged involvement must be assessed separately from the conduct of any other alleged perpetrator.

Two additional charges concern October 20, 2012. One alleges liability under section 11.2, while the other invokes joint commission under section 11.2A. Although both charges arise from the same date, each requires proof of the applicable elements and the accused's responsibility for the particular alleged killing.

The victims' status is one issue among several. The prosecution must establish causation, the relevant mental elements, the connection with a non-international armed conflict, and the alleged mode of participation. Section 5.6 of the Criminal Code supplies default fault elements where the offense does not expressly specify them, while sections 11.2 and 11.2A impose additional requirements concerning complicity or joint commission.

The 2024 amendment may become relevant if the prosecution relies upon the expanded statutory meaning of hors de combat to establish protected status. Its significance would be different if the evidence independently establishes that a victim was not taking an active part in hostilities under the historical wording of section 268.70.

The latter possibility is supported by the inclusive structure of subsection 268.70(2), but it remains an interpretive position rather than a judicial determination in this prosecution. The court must apply the relevant legislation to the evidence presented, without treating either interpretation as established merely because it is consistent with an underlying international humanitarian prohibition.

6.2 Legal Challenges and the Criminal Court's Determination

A legal challenge concerning the retrospective amendment could involve statutory interpretation, constitutional validity, or the application of criminal legality principles. These arguments require distinct analysis because they concern different aspects of the legislation's operation.

A challenge to statutory interpretation might concern whether the amended definition affects the protected-person requirement under section 268.70 as applicable to conduct from 2009–2012. A constitutional challenge would concern Parliament's authority to enact or apply the measure. An argument based on international human rights obligations would require separate consideration of Article 15 of the ICCPR and its domestic legal significance.

The consequences of a successful argument would depend upon what the court decided. A finding that the amended definition has no material effect on a particular charge would differ from a finding that its application is legally impermissible. Neither would automatically establish whether the accused committed the alleged acts or whether every other element of the offense could be proved.

The criminal proceedings also involve substantial evidentiary and procedural difficulties. The alleged conduct occurred more than a decade before the charges were brought. Witness recollections, operational records, the reliability of historical evidence, and the treatment of classified military information may all require judicial consideration.

The National Security Information (Criminal and Civil Proceedings) Act 2004 provides mechanisms for managing sensitive information in proceedings. On September 1, 2026, orders were made under section 22 of that Act following an application on behalf of the Commonwealth. Several suppression and nonpublication orders remain in force (CDPP, 2026).

Those orders limit the publicly available procedural record. They also reinforce the need to distinguish publicly disclosed allegations from evidence admitted and tested in criminal proceedings. The existence of earlier civil findings does not displace the prosecution's burden or the accused's procedural protections.

As of October 22, 2026, the matter had not reached a substantive criminal trial. The Commonwealth Director of Public Prosecutions identified December 8, 2026, as the next scheduled appearance at the Downing Centre Local Court for a further brief-service mention. Hearings concerning final suppression and nonpublication orders were listed for August 2027.

The defendant retains the presumption of innocence, and the prosecution must prove guilt beyond reasonable doubt. No criminal court has yet determined the constitutional validity or precise application of the 2024 retrospective amendment to Roberts-Smith's charges.

Conclusion

Australia's 2024 amendment to the definition of hors de combat is expressly retrospective, but its retrospective operation does not automatically make it unconstitutional. Australian constitutional law permits retrospective criminal legislation within the limits of Commonwealth legislative power and the separation of judicial authority. International law also recognizes the prosecution of conduct that was already criminal when committed, subject to the requirements of legality.

The prohibition against murdering detained or otherwise defenseless persons was firmly established under international humanitarian law before the alleged killings in Afghanistan. The more difficult question concerns the historical Commonwealth offense. Section 268.70, as applicable during 2009–2012, criminalized the killing of persons not taking an active part in hostilities. The organized-armed-group provisions inserted prospectively in 2016 cannot simply be treated as elements governing those earlier events.

The 2024 amendment broadened a statutory definition incorporated into that offense. Its effect depends on whether the revised definition is necessary to establish protected status under the applicable law or whether the historical provision independently covers the alleged conduct. The inclusive wording of section 268.70(2) provides grounds for the latter interpretation, but the relationship has not been conclusively determined in Roberts-Smith's criminal proceedings.

The legality of the amendment and the accused's criminal responsibility remain separate questions. The amendment's enactment does not establish guilt, and the earlier civil findings cannot substitute for proof beyond reasonable doubt. The criminal court must determine the applicable statutory requirements, resolve any material dispute concerning retrospectivity, and assess the evidence relating to each charge.

References

Attorney-General’s Department (n.d.) Prohibition on retrospective criminal laws [online]. Australian Government. Available at: https://www.ag.gov.au/rights-and-protections/human-rights-and-anti-discrimination/human-rights-scrutiny/public-sector-guidance-sheets/prohibition-retrospective-criminal-laws (Accessed: 22 October 2026).

Australian Law Reform Commission (2015) Traditional Rights and Freedoms—Encroachments by Commonwealth Laws. ALRC Report 129. Sydney: Australian Law Reform Commission. Available at: https://www.alrc.gov.au/publication/traditional-rights-and-freedoms-encroachments-by-commonwealth-laws-alrc-report-129/13-retrospective-laws/laws-with-retrospective-operation-2/ (Accessed: 22 October 2026).

Commonwealth Director of Public Prosecutions (2026) Attorney-General (Cth) v Benjamin Roberts-Smith [online]. Commonwealth of Australia. Available at: https://www.cdpp.gov.au/newsroom/attorney-general-cth-v-benjamin-roberts-smith (Accessed: 22 October 2026).

Criminal Code Act 1995 (Cth), No. 12 of 1995, as amended. Federal Register of Legislation. Available at: https://www.legislation.gov.au/C2004A04868/latest/details (Accessed: 22 October 2026).

Criminal Code Amendment (War Crimes) Act 2016 (Cth), No. 97 of 2016, assented to 7 December 2016. Federal Register of Legislation. Available at: https://www.legislation.gov.au/C2016A00097/asmade/2016-12-07/text/original/epub/OEBPS/document_1/document_1.html (Accessed: 22 October 2026).

Crimes and Other Legislation Amendment (Omnibus No. 1) Act 2024 (Cth), No. 93 of 2024, assented to 24 October 2024, Schedule 7. Federal Register of Legislation. Available at: https://www.legislation.gov.au/C2024A00093/asmade/text (Accessed: 22 October 2026).

Evidence Act 1995 (Cth), No. 2 of 1995, as amended. Federal Register of Legislation. Available at: https://www.legislation.gov.au/C2004A04858/latest/details (Accessed: 22 October 2026).

Farid, F. (2026) ‘“Never committed a war crime”: Roberts-Smith argues’, Australian Associated Press, 22 October. Available at: https://www.countrynews.com.au/national/didnt-bloody-murder-roberts-smith-interview-airs/ (Accessed: 22 October 2026).

Federal Court of Australia (2023) Roberts-Smith v Fairfax Media Publications Pty Ltd (No 41), judgment, 1 June 2023, [2023] FCA 555. Available at: https://www.fedcourt.gov.au/services/access-to-files-and-transcripts/online-files/ben-roberts-smith-appeal (Accessed: 22 October 2026).

Federal Court of Australia (2025) Roberts-Smith v Fairfax Media Publications Pty Ltd, appeal judgment, 16 May 2025, [2025] FCAFC 67. Available at: https://www.fedcourt.gov.au/services/access-to-files-and-transcripts/online-files/ben-roberts-smith-appeal (Accessed: 22 October 2026).

Geneva Conventions of 12 August 1949 (1949) Four Conventions adopted at Geneva on 12 August 1949, Common Article 3. Available at: https://ihl-databases.icrc.org/en/ihl-treaties/gci-1949/article-3 (Accessed: 22 October 2026).

High Court of Australia (1938) Briginshaw v Briginshaw, judgment, 30 June 1938, [1938] HCA 34; (1938) 60 CLR 336. Available at: https://www.hcourt.gov.au/cases-and-judgments/judgments/1-clr-100-clr/briginshaw-v-briginshaw (Accessed: 22 October 2026).

High Court of Australia (1991) Polyukhovich v Commonwealth, judgment, 14 August 1991, [1991] HCA 32; (1991) 172 CLR 501. Available at: https://derechos.org/intlaw/doc/polyukhovich.html (Accessed: 22 October 2026).

High Court of Australia (2025) Roberts-Smith v Fairfax Media Publications Pty Ltd & Ors, special leave disposition, 4 September 2025, [2025] HCADisp 212. Available at: https://www.hcourt.gov.au/cases-and-judgments/judgments/special-leave-dispositions/roberts-smith-v-fairfax-media-publications-pty-ltd-acn-003-357-720-ors (Accessed: 22 October 2026).

Inspector-General of the Australian Defence Force (2020) Inspector-General of the Australian Defence Force Afghanistan Inquiry Report. Public Release Version. Canberra: Australian Government Department of Defence. Available at: https://www.defence.gov.au/sites/default/files/2021-10/IGADF-Afghanistan-Inquiry-Public-Release-Version.pdf (Accessed: 22 October 2026).

International Covenant on Civil and Political Rights (1966) Adopted 16 December 1966, entered into force 23 March 1976, 999 UNTS 171. Available at: https://www.ohchr.org/sites/default/files/ccpr.pdf (Accessed: 22 October 2026).

International Criminal Court (Consequential Amendments) Act 2002 (Cth), No. 42 of 2002, assented to 27 June 2002. Federal Register of Legislation. Available at: https://www.legislation.gov.au/Series/C2004A00993 (Accessed: 22 October 2026).

International Committee of the Red Cross (2005) Customary International Humanitarian Law, Volume I: Rules, Rule 47: Attacks against Persons Hors de Combat. Cambridge: Cambridge University Press. Available at: https://ihl-databases.icrc.org/en/customary-ihl/v1/rule47 (Accessed: 22 October 2026).

National Security Information (Criminal and Civil Proceedings) Act 2004 (Cth), No. 150 of 2004, as amended. Federal Register of Legislation. Available at: https://www.legislation.gov.au/C2004A01385/latest (Accessed: 22 October 2026).

Parliament of Australia (2024) Crimes and Other Legislation Amendment (Omnibus No. 1) Bill 2024: Supplementary Explanatory Memorandum. Canberra: Parliament of Australia. Available at: https://parlinfo.aph.gov.au/parlInfo/download/legislation/ems/r7172_ems_33cb6845-44b8-4800-8967-6d11dc953953/upload_pdf/JC014033.pdf;fileType=application/pdf (Accessed: 22 October 2026).

Parliament of Australia (2026a) Senate Debates: Statute Update Bill 2026; Limitation of Debate, 10 September 2026. Available at: https://www.openaustralia.org.au/senate/?id=2026-09-10.213.1 (Accessed: 22 October 2026).

Parliament of Australia (2026b) House of Representatives Debates: Statute Update Bill 2026; Consideration of Senate Message, 14 September 2026. Available at: https://www.openaustralia.org.au/debates/?id=2026-09-14.32.2 (Accessed: 22 October 2026).

Protocol Additional to the Geneva Conventions of 12 August 1949, and relating to the Protection of Victims of International Armed Conflicts (Protocol I) (1977) Adopted 8 June 1977, entered into force 7 December 1978, 1125 UNTS 3, Article 41. Available at: https://ihl-databases.icrc.org/en/ihl-treaties/api-1977/article-41 (Accessed: 22 October 2026).

Rome Statute of the International Criminal Court (1998) Adopted 17 July 1998, entered into force 1 July 2002, 2187 UNTS 3. Available at: https://www.icc-cpi.int/publications/core-legal-texts/rome-statute-international-criminal-court (Accessed: 22 October 2026).

Senate Standing Committee for the Scrutiny of Bills (2024) Scrutiny Digest 12/24. Canberra: Parliament of Australia. Available at: https://www.aph.gov.au/-/media/Committees/Senate/committee/scrutiny/scrutiny_digest/2024/d12_24.pdf (Accessed: 22 October 2026).