Rules regarding the conduct of hostilities (international humanitarian law): HSC Legal Studies

What this dot point is asking

Rules regarding the conduct of hostilities is one of the four contemporary issues that must be studied in the World Order option of the Legal Studies Stage 6 Syllabus (2009). You must identify and investigate the issue and evaluate the effectiveness of legal and non-legal responses to it.

This is the law of jus in bello, or international humanitarian law (IHL): the rules that apply once an armed conflict exists, whether or not the resort to force was lawful. A strong answer explains the main treaties and principles, shows how they are enforced by states, courts, the ICRC, NGOs and the media, and judges their effectiveness with current evidence from conflicts such as Ukraine, Gaza and Sudan, and from Australia's own war crimes investigations.

The answer

Why rules for war?

Wars will happen, so IHL aims to limit suffering by protecting those who are not, or no longer, taking part in hostilities (civilians, the wounded, prisoners) and by restricting the means and methods of warfare. It grew from the work of Henri Dunant, whose account of the Battle of Solferino (1859) led to the founding of the Red Cross movement (1863) and the first Geneva Convention (1864).

IHL is separate from jus ad bellum: it binds the aggressor and the defender equally, and a state acting lawfully in self-defence must still obey it. It also differs from human rights law, which continues to apply in armed conflict but was designed for peacetime.

Sources of the rules

Hague law regulates the means and methods of warfare. The Hague Conventions of 1899 and 1907 and their Regulations (1907) govern who is a combatant, prohibited weapons and methods, and the rules of military occupation.

Geneva law protects people in the power of the enemy. The four Geneva Conventions 1949 have 196 states parties, the only treaties with universal participation:

• Convention I: wounded and sick members of armed forces on land;
• Convention II: wounded, sick and shipwrecked at sea;
• Convention III: prisoners of war, who must be treated humanely and released at the end of hostilities;
• Convention IV: civilians in enemy hands, including in occupied territory (for example, the ban on transferring an occupier's own population into occupied territory, art 49).

Common article 3, in all four Conventions, gives minimum protections in non-international armed conflicts: humane treatment, and bans on murder, torture, hostage-taking and trials without due process.

Additional Protocols 1977. Protocol I (international armed conflicts, including wars of self-determination) codified the rules on the conduct of hostilities; more than 170 states are parties. Protocol II (non-international armed conflicts) extends protections in civil wars; about 169 states are parties. Australia ratified both in 1991. The United States, Israel, India and Iran are not parties to Protocol I, though many of its rules are customary.

Weapons treaties.

• Biological Weapons Convention 1972 and Chemical Weapons Convention 1993 (in force 1997), which bans the development, stockpiling and use of chemical weapons and is monitored by the Organisation for the Prohibition of Chemical Weapons (OPCW). The OPCW has attributed chemical weapons attacks in Syria to the former Syrian government and to Islamic State.
• Convention on Certain Conventional Weapons 1980 and its protocols (such as blinding lasers and explosive remnants of war).
• Ottawa Convention 1997 (anti-personnel mines) and Convention on Cluster Munitions 2008. Australia is a party to both.
• Treaty on the Prohibition of Nuclear Weapons 2017 (in force 22 January 2021). Australia and the nuclear-armed states are not parties. In the Nuclear Weapons advisory opinion (1996) the ICJ held that the use of nuclear weapons would generally be contrary to IHL but could not conclude definitively whether it would be lawful in an extreme circumstance of self-defence in which a state's very survival was at stake.

Customary IHL. Many rules bind all states and armed groups as custom, as the ICRC's Customary IHL Study (2005) documents.

The core principles

• Distinction (AP I arts 48, 51 and 52). Attacks may be directed only at combatants and military objectives, never at civilians or civilian objects. Indiscriminate attacks are prohibited.
• Proportionality (AP I art 51(5)(b)). An attack is prohibited if the expected incidental civilian harm would be excessive in relation to the concrete and direct military advantage anticipated.
• Precaution (AP I art 57). Parties must do everything feasible to verify targets, choose means and methods that minimise civilian harm, and give effective advance warning where circumstances permit.
• Unnecessary suffering (AP I art 35(2)). Weapons and methods causing superfluous injury or unnecessary suffering are banned.
• Military necessity and humanity. Force must be needed for a legitimate military purpose, and humane treatment is owed to all persons in the enemy's power. The Martens clause provides that where no treaty rule applies, people remain protected by "the principles of humanity and the dictates of public conscience".

Also protected: medical units and personnel, humanitarian workers, cultural property, objects indispensable to the survival of the civilian population (starvation of civilians as a method of warfare is prohibited, AP I art 54), and the natural environment.

Enforcement: legal responses

1. States. Every state must respect and ensure respect for the Conventions (common article 1), train its forces and investigate violations. For grave breaches, such as wilful killing, torture and extensive unlawful destruction, every state must search for suspects and prosecute or extradite them, regardless of nationality (universal jurisdiction).

2. International courts.

• The ICTY and ICTR (1993 and 1994) developed the law of war crimes, including rules for internal conflicts (Tadic, 1995).
• The ICC prosecutes war crimes under Rome Statute art 8. In 2024 it issued warrants for senior Russian commanders over strikes on Ukraine's electricity infrastructure, and for Israeli leaders (including over starvation as a method of warfare, which Israel rejects) and Hamas leaders in the Palestine situation. Bosco Ntaganda (2019) and Dominic Ongwen (2021) were convicted of war crimes.
• The ICJ decides state responsibility (for example, the Wall advisory opinion, 2004, on the application of the Fourth Geneva Convention in occupied territory).

3. Australia's implementation. The Geneva Conventions Act 1957 (Cth) gives the Conventions force in Australian law, and Division 268 of the Criminal Code Act 1995 (Cth) creates war crimes offences mirroring the Rome Statute. Australia's defence forces operate under rules of engagement and legal advice from military lawyers.

• The Brereton Report. The Inspector-General of the ADF's Afghanistan Inquiry Report, released on 19 November 2020, found credible information of 39 unlawful killings of prisoners and civilians by or involving 25 current or former Australian special forces personnel between 2005 and 2016. The government created the Office of the Special Investigator (2021) to investigate with the Australian Federal Police.
• Prosecutions. Former SAS soldier Oliver Schulz was charged in March 2023 with the war crime of murder (Criminal Code s 268.70), the first such charge against an Australian soldier; his trial had not begun as at September 2026. In April 2026 Ben Roberts-Smith was charged with five counts of the war crime of murder; the charges have not been tested at trial and he is presumed innocent. (Separately, in civil defamation proceedings, the Federal Court found in 2023, on the civil standard of proof, that he was complicit in the murder of four unarmed Afghan men; his appeals failed in 2025.) The OSI has also closed many investigations without charges.

Enforcement: non-legal responses

• The ICRC. Mandated by the Conventions, the International Committee of the Red Cross visits prisoners of war and detainees, traces missing persons, delivers aid and raises violations confidentially with the parties. Confidentiality gains access but limits public pressure.
• NGOs and investigators. Human Rights Watch, Amnesty International and open-source investigators document attacks, and UN commissions of inquiry gather evidence for future prosecution.
• The media. Reporting creates political pressure. The ABC's "Afghan Files" (2017) helped expose the allegations examined by Brereton.
• State diplomacy. After an Israeli strike killed Australian aid worker Zomi Frankcom and six World Central Kitchen colleagues in Gaza on 1 April 2024, the Australian government demanded full accountability and appointed Air Chief Marshal (ret'd) Mark Binskin as a special adviser; Israel dismissed two officers after its own inquiry.
• Humanitarian assessments. The Integrated Food Security Phase Classification (IPC) confirmed famine in Gaza Governorate in August 2025; Israel rejected the finding. Such findings shape debate about starvation and humanitarian access.

Current challenges

• Ukraine. The UN has documented thousands of civilian deaths and repeated strikes on energy infrastructure, and Russia and Ukraine accuse each other of mistreating prisoners of war. The ICC's warrants have not been executed.
• Gaza. The scale of civilian deaths and destruction and restrictions on aid have made distinction, proportionality and starvation central legal issues; Israel says it complies with IHL and blames Hamas for operating among civilians.
• Sudan. Both the Sudanese Armed Forces and the Rapid Support Forces have been accused by UN investigators of war crimes, including attacks on displaced people's camps and on El Fasher (2025).
• Erosion of weapons bans. Estonia, Latvia and Lithuania left the Ottawa Convention from 27 December 2025, Finland from January 2026 and Poland from February 2026, citing the threat from Russia; Lithuania left the Convention on Cluster Munitions in March 2025. Ukraine did not lodge a withdrawal, which under article 20 could not take effect while it is engaged in armed conflict; instead it notified in 2025 that it was suspending the operation of the Convention from 17 July 2025.
• New technology. Drones, cyber operations and AI-enabled targeting test existing rules. The UN Secretary-General and the ICRC President called in 2023 for a legally binding instrument on autonomous weapons by 2026; negotiations continue through the Convention on Certain Conventional Weapons and the General Assembly.

Evaluating the effectiveness of the rules

Judgement. The rules regarding the conduct of hostilities are effective as standards but only partially effective in practice. They are accepted by every state, shape how professional militaries plan and train, and create the evidence and legal basis for accountability, as Australia's own war crimes process shows. But compliance depends on states' willingness to restrain and investigate their own forces, international enforcement is slow and selective, and in the major conflicts of 2022 to 2026 civilians have borne very heavy costs. Law reform is also moving in both directions: new concerns about autonomous weapons, but withdrawals from existing weapons bans.

In one sentence

The rules regarding the conduct of hostilities, from the Hague and Geneva Conventions to modern weapons treaties, are universally accepted standards of distinction, proportionality and humane treatment, but because their enforcement depends on states, the ICRC's persuasion and slow international courts, they have been only partially effective in limiting harm in the conflicts of 2022 to 2026.

Try this

Q1. Outline the protections given by the four Geneva Conventions 1949. (4 marks)

• What the marker wants. Each Convention's protected group, common article 3 and the universal ratification point.

Q2. Explain how Australia enforces the rules regarding the conduct of hostilities. (6 marks)

• What the marker wants. The Geneva Conventions Act 1957, Division 268, the Brereton Report, the OSI and the Schulz prosecution, with a comment on effectiveness.

Q3. To what extent are non-legal measures effective in promoting compliance with international humanitarian law? (8 marks)

• What the marker wants. The ICRC, NGOs, media and diplomacy with examples, compared with legal measures, and a judgement.