(a) Is it a legal duty of States under international law to settle their disputes by peaceful means? Can failure of peaceful…

(a) A legal duty of peaceful settlement

• Before the Charter: the Hague Conventions for the Pacific Settlement of International Disputes (1899, 1907), the League Covenant and the Kellogg–Briand Pact (1928), which renounced war as an instrument of national policy.
• Under the UN Charter:
• Art 2(3): all members "shall settle their international disputes by peaceful means in such a manner that international peace and security, and justice, are not endangered";
• Art 33(1): parties to a dispute likely to endanger peace "shall, first of all, seek a solution" by negotiation, enquiry, mediation, conciliation, arbitration, judicial settlement, resort to regional agencies, or other peaceful means of their choice;
• Art 37: if the parties fail, they shall refer the dispute to the Security Council.
• A customary obligation: the duty is reaffirmed in the Friendly Relations Declaration (GA Res 2625, 1970) and the Manila Declaration on the Peaceful Settlement of Disputes (1982). The ICJ treated it as customary in Nicaragua v USA (1986).
• Its content: it is a duty of conduct, to seek settlement in good faith. It is not a duty to reach a settlement.
• States have free choice of means.
• No State can be compelled to accept adjudication without its consent (Status of Eastern Carelia (PCIJ, 1923); Art 36 of the ICJ Statute).
• Negotiations must be meaningful, not formal (North Sea Continental Shelf (1969)).

Does the failure of peaceful means permit force?

• No. The prohibition on force stands on its own:
• Art 2(4) prohibits the threat or use of force against the territorial integrity or political independence of any State, or in any manner inconsistent with the purposes of the UN;
• it is a rule of customary law and widely regarded as jus cogens (Nicaragua);
• the Friendly Relations Declaration states that the prohibition applies to the settlement of territorial and boundary disputes.
• The only exceptions:
• self-defence against an armed attack (Art 51), subject to necessity and proportionality (Nicaragua; Oil Platforms (2003)) and to reporting to the Security Council;
• enforcement action authorised by the Security Council under Chapter VII (Arts 39–42).
• Rejected justifications:
• reprisals involving force are unlawful (Friendly Relations Declaration);
• the Court rejected a right of intervention in Corfu Channel (1949);
• the failure of negotiations is not an armed attack.
• What States can do when peaceful means fail:
• refer the dispute to the Security Council (Art 37);
• take lawful countermeasures not involving force, which must be proportionate and reversible (ILC Articles on State Responsibility, 2001, Arts 49–53);
• seek adjudication where jurisdiction exists.
• Practice: force used under the pretext of an unresolved dispute has been condemned:
• Iraq's invasion of Kuwait (1990);
• Argentina's invasion of the Falklands (1982), where Security Council Resolution 502 demanded withdrawal;
• Russia–Ukraine (2022), condemned by GA Resolution ES-11/1.
• India's practice: India favours peaceful and bilateral settlement, as in the Simla Agreement (1972) and the Indus Waters Treaty's mechanisms, together with its right of self-defence.
• Conclusion: peaceful settlement is a binding duty. Its failure never, by itself, entitles a State to use force.

(b) The request and the Court's opinion

• The request: the General Assembly requested an opinion in 1994. A separate request by the WHO was declined, because the question fell outside the WHO's competence.
• **Opinion of 8 July 1996, Legality of the Threat or Use of Nuclear Weapons:**
• (A) Unanimously: there is no specific authorisation of the threat or use of nuclear weapons in customary or conventional law.
• (B) By 11 votes to 3: there is no comprehensive and universal prohibition of them as such.
• (C) Unanimously: a threat or use contrary to Art 2(4) and not meeting the requirements of Art 51 is unlawful. The Charter's provisions apply to any use of force, whatever the weapon.
• (D) Unanimously: any threat or use must comply with international humanitarian law:
• the principle of distinction and the ban on indiscriminate weapons;
• the prohibition of unnecessary suffering;
• the Martens Clause;
• neutrality;
• treaty obligations.
• (E) By 7 votes to 7, on the President's casting vote (Bedjaoui):
• the threat or use of nuclear weapons would be generally contrary to the rules of IHL;
• however, the Court cannot conclude definitively whether it would be lawful or unlawful in "an extreme circumstance of self-defence, in which the very survival of a State would be at stake".
• (F) Unanimously: there is an obligation to pursue in good faith and bring to a conclusion negotiations leading to nuclear disarmament (NPT Art VI).
• Other points in the opinion:
• a "threat" is unlawful if the contemplated use would be unlawful;
• policies of deterrence were noted but not assessed;
• environmental obligations are relevant factors in assessing necessity and proportionality.

Answer to the question

• Generally, no. The use of nuclear weapons would almost always violate IHL, given their uncontrollable blast, heat and radiation effects.
• One open question: the Court left open, as a non liquet, a possible exception for survival-level self-defence.
• Criticism: several judges criticised this gap:
• Weeramantry, Shahabuddeen and Koroma (dissenting) argued for total illegality;
• Schwebel and Higgins considered that the Court should have decided.

Later developments

• TPNW: the Treaty on the Prohibition of Nuclear Weapons (2017), in force since 2021, bans the development, possession, threat and use of nuclear weapons. However, no nuclear-armed State, including India, is a party.
• ***Marshall Islands v India* (2016):** the ICJ dismissed the case for lack of a dispute. The case sought to enforce the disarmament obligation.
• India: India is outside the NPT. It maintains credible minimum deterrence, no first use, and no use against non-nuclear-weapon States, and supports a universal, non-discriminatory nuclear weapons convention.

(c) Normative development

• Stockholm Conference on the Human Environment (1972):
• the Stockholm Declaration, Principle 1 (the right to an environment of quality) and Principle 21 (sovereignty over resources together with the duty not to cause transboundary harm);
• the creation of the UN Environment Programme (UNEP).
• World Charter for Nature (1982) and the Brundtland Report (1987), which set out sustainable development.
• Rio Earth Summit (1992):
• the Rio Declaration, including precaution (Principle 15), polluter pays (Principle 16), environmental impact assessment (Principle 17) and common but differentiated responsibilities (Principle 7);
• Agenda 21;
• the UNFCCC, the Convention on Biological Diversity and, later, the UNCCD (1994).
• Later summits: Johannesburg (2002), Rio+20 (2012), and the 2030 Agenda and SDGs (2015), especially Goals 6, 13, 14 and 15.

Treaties sponsored or facilitated by the UN

• Ozone: the Vienna Convention (1985) and the Montreal Protocol (1987, with the Kigali Amendment of 2016), the most successful regime.
• Climate: the Kyoto Protocol (1997) and the Paris Agreement (2015), with nationally determined contributions and the 1.5–2°C goal.
• Biodiversity: the Cartagena and Nagoya Protocols, and the Kunming–Montreal Global Biodiversity Framework (2022), with its "30×30" target.
• Hazardous substances: the Basel, Rotterdam and Stockholm Conventions, and the Minamata Convention on mercury (2013).
• Oceans:
• UNCLOS Part XII;
• the BBNJ Agreement (2023, in force January 2026).

Institutions

• UNEP and the UN Environment Assembly, which launched the negotiations on a plastics treaty (2022). These remain unfinished after the 2025 sessions.
• IPCC, which provides scientific assessment.
• The Global Environment Facility and the Green Climate Fund, which provide finance.
• The Loss and Damage Fund (COP27–28).

Rights and adjudication

• A right to a healthy environment: the General Assembly (Resolution 76/300, 2022) and the Human Rights Council (48/13, 2021) recognised the right to a clean, healthy and sustainable environment.
• ICJ advisory opinion on the obligations of States in respect of climate change (23 July 2025): States have binding obligations under treaties and customary law, including due diligence to prevent significant harm. A breach may entail State responsibility.
• ITLOS advisory opinion (2024): greenhouse gas emissions are marine pollution under UNCLOS.

Impact on India

• Legislation: the Water Act (1974), Air Act (1981) and Environment (Protection) Act (1986), enacted to implement the Stockholm decisions, and the NGT Act (2010).
• Case law: the Supreme Court absorbed the UN principles into Art 21:
• Vellore Citizens' Welfare Forum v Union of India (1996), on precaution and polluter pays;
• M.C. Mehta cases;
• M.K. Ranjitsinh v Union of India (2024), on a right against the adverse effects of climate change.

Assessment

• Achievements: the UN has been the principal norm-setter and convener.
• Weaknesses:
• weak enforcement;
• the finance gap;
• the US withdrawal from Paris (2025);
• fragmented regimes.
• Needed: stronger compliance mechanisms, climate finance, and recognition of the rights of future generations.