Responses to conflict: jus ad bellum and jus in bello: HSC Legal Studies

What this dot point is asking

Part 2 of the World Order option (Legal Studies Stage 6 Syllabus 2009) lists political negotiation, persuasion and the use of force as responses to world order, and asks you to evaluate the effectiveness of legal and non-legal measures in resolving conflict and working towards world order. To do that you need the law on when force is lawful (jus ad bellum) and an outline of the law on how it may be used (jus in bello, covered fully under the contemporary issue "rules regarding the conduct of hostilities").

This is heavily examined: a question on resolving conflict, compliance or the effectiveness of the law in world order needs accurate Charter articles, ICJ cases and current conflicts described neutrally, with claims attributed to the states that make them.

The answer

Three ways to respond to conflict

1. Political negotiation. Direct talks between the parties, or talks helped by a third party (good offices, mediation, conciliation). Article 33 of the Charter requires parties to a dispute likely to endanger peace to seek a solution first by "negotiation, enquiry, mediation, conciliation, arbitration, judicial settlement" or other peaceful means.

• Examples. The Camp David Accords (1978) between Egypt and Israel; the Good Friday Agreement (1998) in Northern Ireland; the Gaza ceasefire of October 2025, mediated by the United States, Egypt, Qatar and Turkey, which was followed by Security Council Resolution 2803 (17 November 2025); the ceasefire between the United States and Iran brokered by Pakistan in April 2026, which later broke down. US-led talks on ending the Russia-Ukraine war had produced no agreement as at September 2026.
• Strengths. Outcomes are consensual, so they respect sovereignty and are more likely to last.
• Weaknesses. Parties can stall or walk away; agreements may reward aggression; ceasefires often collapse.

2. Persuasion. Using pressure, incentives and legitimacy to change a state's behaviour without force.

• Diplomatic persuasion. Statements, votes and resolutions, such as General Assembly Resolution ES-11/1 (2 March 2022) demanding Russia withdraw from Ukraine.
• Legal persuasion. Taking a state to the ICJ or supporting the ICC, which creates authoritative findings of illegality.
• Economic persuasion: sanctions. UN sanctions under article 41 bind all members, and Australia implements them through the Charter of the United Nations Act 1945 (Cth). States also impose autonomous sanctions: Australia uses the Autonomous Sanctions Act 2011 (Cth), and by February 2026 had imposed more than 1,800 sanctions in response to Russia's invasion of Ukraine, including on "shadow fleet" oil tankers. UN sanctions on Iran were reimposed in late September 2025 after France, Germany and the United Kingdom used the "snapback" in Resolution 2231 (2015).
• Strengths. Sanctions raise the cost of wrongdoing and signal the international community's view.
• Weaknesses. Targets adapt and evade sanctions (Russia redirected oil exports); sanctions can hurt civilians; unilateral sanctions lack universality.

3. The use of force. Lawful only within the Charter's narrow exceptions, below. It can stop aggression or atrocities, but it is costly, unpredictable and often contested.

Jus ad bellum: the prohibition on force

Article 2(4) of the Charter of the United Nations 1945:

All Members shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any state, or in any other manner inconsistent with the Purposes of the United Nations.

The prohibition is also customary international law (Nicaragua v United States, 1986) and is widely regarded as jus cogens. General Assembly Resolution 3314 (1974) defines aggression, including invasion, bombardment, blockade and sending armed bands. Planning and leading aggression is now an international crime (Rome Statute art 8 bis, jurisdiction activated in 2018).

Exception 1: self-defence (article 51)

Article 51 preserves "the inherent right of individual or collective self-defence if an armed attack occurs", until the Security Council takes measures to maintain peace. Measures taken must be reported immediately to the Council.

Requirements.

• An armed attack. In Nicaragua v United States (1986) the ICJ held that only the "most grave forms" of force amount to an armed attack, and that supplying weapons or logistical support to rebels does not.
• Necessity and proportionality. From the Caroline incident (1837), where the necessity of self-defence had to be "instant, overwhelming, leaving no choice of means, and no moment for deliberation". The ICJ confirmed these requirements in Nicaragua and in Oil Platforms (Iran v United States, 2003), where it rejected US claims that attacks on Iranian oil platforms were necessary self-defence.
• Collective self-defence requires the victim state to declare it has been attacked and request help (Nicaragua).

Contested extensions.

• Anticipatory self-defence against an imminent attack has some support; pre-emptive force against a threat that is not imminent (the "Bush doctrine" used to justify the 2003 invasion of Iraq) is generally rejected. UN Secretary-General Kofi Annan described the Iraq invasion as illegal in 2004.
• Non-state actors. In the Wall advisory opinion (2004) the ICJ read article 51 as concerning armed attacks by one state against another. After 11 September 2001, the Security Council recognised the right of self-defence (Resolutions 1368 and 1373), and many states have since used force against terrorist groups in states said to be "unwilling or unable" to stop them. In September 2015 Australia notified the Security Council that it was extending air strikes against ISIL into Syria in the collective self-defence of Iraq. Other states reject the doctrine.
• Armed Activities on the Territory of the Congo (DRC v Uganda, 2005). The ICJ found Uganda violated article 2(4) by its military operations in the DRC and rejected its self-defence claim; in 2022 it ordered Uganda to pay US$325 million in reparations.

Exception 2: Security Council authorisation

Under Chapter VII, once the Council determines a threat to the peace, breach of the peace or act of aggression (art 39), it may authorise force (art 42), usually by permitting member states to use "all necessary means". Examples:

• Korea, Resolution 84 (1950), possible only because the Soviet Union was boycotting the Council;
• Iraq and Kuwait, Resolution 678 (1990), which authorised the coalition that expelled Iraq from Kuwait in 1991;
• Timor-Leste, Resolution 1264 (1999), authorising the Australian-led INTERFET with Indonesia's consent;
• Libya, Resolution 1973 (2011), authorising measures to protect civilians. Russia, China and others argued that NATO went beyond protecting civilians to regime change, which has made them more reluctant to authorise force since.

Regional organisations may act under Chapter VIII (arts 52 and 53), but enforcement action by them needs Council authorisation.

Other claimed justifications

• Consent (intervention by invitation). Force at the request of a lawful government is generally accepted, such as Iraq's request for help against ISIL in 2014.
• Humanitarian intervention. NATO's 1999 bombing of Yugoslavia over Kosovo had no Council authorisation; the Independent International Commission on Kosovo called it "illegal but legitimate". The United Kingdom relied on humanitarian intervention for the 2018 strikes on Syrian chemical weapons facilities. Most states do not accept it as a legal exception, which is why R2P (2005) channels coercive action through the Security Council.

Contemporary conflicts and the law

Describe these neutrally, attributing claims to those who make them.

Russia and Ukraine (from 24 February 2022)

Russia claimed collective self-defence of the self-declared Donetsk and Luhansk "republics" and alleged genocide against Russian speakers. The General Assembly deplored Russia's "aggression" (ES-11/1, 141 votes to 5), and the ICJ ordered Russia to suspend military operations (16 March 2022), observing that it was doubtful the Genocide Convention authorised unilateral force to prevent genocide. Russia did not comply. In 2024 the Court confirmed it had jurisdiction only over Ukraine's request for a declaration that it had not committed genocide; the case continues. Security Council Resolution 2774 (24 February 2025) called for a swift end to the conflict without naming an aggressor.

Israel and Gaza (from 7 October 2023)

Hamas-led attacks on Israel on 7 October 2023 killed about 1,200 people and took about 250 hostages. Israel invoked self-defence; critics, relying partly on the Wall advisory opinion and Israel's status as occupying power, argued that article 51 does not apply to force used in occupied territory and that Israel's conduct was disproportionate. Tens of thousands of Palestinians were killed, according to the Gaza Health Ministry. The ICJ ordered provisional measures in South Africa v Israel (from January 2024), the ICC issued arrest warrants for Israeli and Hamas leaders (November 2024), and after a ceasefire in October 2025 the Security Council endorsed a peace plan in Resolution 2803.

Iran (June 2025 and from 28 February 2026)

In June 2025 Israel struck Iranian nuclear and military sites, describing the strikes as pre-emptive self-defence against Iran's nuclear programme; the United States struck three nuclear facilities on 22 June, and a ceasefire followed on 24 June. On 28 February 2026 the United States and Israel launched a much larger campaign; Iran's President later said that Supreme Leader Ali Khamenei had been killed in it. The United States said it was acting in self-defence under the Charter; China and others called the strikes unauthorised. Iran retaliated against Israel, US bases and Gulf states and disrupted shipping in the Strait of Hormuz. The Security Council condemned Iran's attacks on its neighbours (Resolution 2817, 11 March 2026) but China and Russia vetoed a draft on protecting shipping (7 April 2026). A Pakistan-mediated ceasefire in April 2026 and a peace agreement in June 2026 broke down when fighting resumed in July 2026. Whether the initial strikes satisfied article 51, given the requirement of an armed attack or at least an imminent one, is sharply disputed.

Jus in bello in outline

International humanitarian law (IHL) governs how force is used once armed conflict exists, and binds all parties equally, whether their resort to force was lawful or not. Its main sources are the Hague Conventions (1899 and 1907), the four Geneva Conventions 1949 (196 states parties), Additional Protocols I and II 1977 and weapons treaties. Core principles are distinction, proportionality, precaution and humanity, with the prohibition on unnecessary suffering. Australia implements the Conventions through the Geneva Conventions Act 1957 (Cth) and criminalises war crimes in Division 268 of the Criminal Code Act 1995 (Cth). This is covered in depth under the contemporary issue on the conduct of hostilities.

Australia's federal government

Australia supports the Charter framework: it relies on article 51 and Security Council authorisations for its deployments, publicly notified the Council of its legal basis for strikes in Syria (2015), uses the Autonomous Sanctions Act 2011 (Cth) against Russia, Iran and others, and supports Ukraine with military and humanitarian aid. It joined the 2003 invasion of Iraq without specific Council authorisation, relying on earlier resolutions, a decision that remains controversial.

Evaluating the effectiveness of responses to conflict

Judgement. The legal framework on force is clear and almost universally accepted in principle, and most states comply most of the time. But it is only partially effective because it relies on self-interpretation: states that use force almost always claim a legal justification, usually self-defence, and the Security Council, the only body that can authoritatively decide, is blocked by the veto whenever a permanent member or its ally is involved. Negotiation and persuasion therefore do most of the work of resolving conflict, and they succeed only when the parties are willing.

In one sentence

International law prohibits force except in self-defence or with Security Council authorisation, and while negotiation and persuasion, including sanctions, resolve most conflicts that are resolved, the reliance on states' own interpretations of article 51 and the veto's block on collective action mean the law on force is only partially effective, as Ukraine, Gaza and the 2026 Iran war show.

Try this

Q1. Outline the requirements for lawful self-defence. (4 marks)

• What the marker wants. Article 51, armed attack, necessity and proportionality, reporting to the Council, and a case (Nicaragua or Oil Platforms).

Q2. Assess the effectiveness of sanctions as a response to conflict. (6 marks)

• What the marker wants. UN and autonomous sanctions, Australian legislation, a current example (Russia or Iran) and a judgement weighing costs against results.

Q3. Evaluate the effectiveness of the law in regulating the use of force in a conflict you have studied. (8 marks)

• What the marker wants. The justifications claimed, the responses of the UN, courts and states, compliance, and a judgement.