I. Obligations under International Treaties: The NPT and Safeguards Agreements with the IAEA
Iran has been a party to the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) since 1970 as a non-nuclear-weapon state. Under Article II of the NPT, Iran is legally prohibited from acquiring or developing nuclear weapons. Article III obliges Iran to accept comprehensive safeguards implemented by the International Atomic Energy Agency (IAEA) on all nuclear material in its territory. Accordingly, Iran concluded a Comprehensive Safeguards Agreementwith the IAEA (INFCIRC/214) in 1974, requiring full declaration of its nuclear material and activities and subjecting them to continuous verification to ensure their exclusive peaceful use.
Iran also agreed in 2003 to implement the Modified Code 3.1, which mandates early design information notification (i.e., informing the IAEA at the planning stage of any new nuclear facility, rather than 180 days before the introduction of nuclear material, as required by the original version). This modification became legally binding and cannot be unilaterally withdrawn by Iran.
Iran has also signed (but not ratified) the Additional Protocol to its Safeguards Agreement, granting the IAEA enhanced inspection powers (including access to undeclared sites). Iran applied the Protocol provisionally during specific periods but has suspended its implementation at various times. As such, Iran’s fundamental international obligations remain anchored in the NPT and the Safeguards Agreement: not to pursue nuclear weapons, to declare all nuclear materials and activities, and to allow IAEA verification.
Failure to comply with these obligations—such as undeclared nuclear material, obstruction of inspections, or refusal to provide design information—may constitute a breach of international obligations and can be reported to the UN Security Council by the IAEA Board of Governors.
II. Obligations under UN Security Council Resolutions (2006–2015) and the JCPOA
Between 2006 and 2010, the UN Security Council adopted six binding resolutions under Chapter VII of the UN Charter (Resolutions 1696, 1737, 1747, 1803, 1835, and 1929) in response to concerns about Iran’s compliance with its IAEA safeguards obligations. These resolutions imposed legally binding obligations, including:
- Suspension of enrichment and heavy water activities, particularly at facilities like Natanz and the IR-40 reactor at Arak;
- Full cooperation with the IAEA, including implementation of the Additional Protocol and Modified Code 3.1;
- Refraining from activities related to ballistic missiles capable of delivering nuclear weapons;
- Targeted sanctions, including bans on arms exports, restrictions on nuclear-related imports, and travel bans for individuals involved in Iran’s nuclear program.
In 2015, the Joint Comprehensive Plan of Action (JCPOA) was concluded between Iran and the P5+1 (China, France, Russia, UK, US + Germany) and the EU. The JCPOA was endorsed by UNSC Resolution 2231, which provided a roadmap for lifting previous sanctions and establishing a framework of nuclear restrictions and enhanced monitoring.
Key JCPOA nuclear commitments by Iran included:
- Limiting uranium enrichment to 3.67% U-235 and keeping stockpiles under 300 kg of UF6;
- Reducing the number of operational centrifuges to 5,060 IR-1 units at Natanz;
- Reconfiguring Fordow and Arak facilities to prevent production of weapons-grade materials;
- Implementing the Additional Protocol and Modified Code 3.1 permanently;
- Accepting the most intrusive verification regime ever established by the IAEA, including real-time monitoring and oversight of the entire fuel cycle.
The JCPOA also established a Joint Commission to resolve disputes, and a “snapback mechanism” allowing the reimposition of UN sanctions in case of significant non-compliance, even without consensus.
Resolution 2231 was less binding than its predecessors in terms of language, using “calls upon” rather than “decides,” reflecting the political (not strictly legal) nature of the JCPOA commitments. Nevertheless, the JCPOA was enforced via reciprocal obligations and IAEA verification.
III. Legal Nature of Iran’s International Obligations
- Treaty-Based Obligations (NPT and Safeguards Agreement)
- Legally binding under international law;
- Violation constitutes an internationally wrongful act and may trigger consequences under general international responsibility rules;
- The NPT allows withdrawal under Article X with 90 days’ notice and justification of “extraordinary events jeopardizing national interests.”
- UN Security Council Resolutions
- Resolutions adopted under Chapter VII (2006–2010) are binding under Article 25 of the UN Charter and take precedence over conflicting treaty obligations (per Article 103 of the Charter);
- Resolution 2231 (2015), however, employs language indicating political encouragement rather than legal obligation for JCPOA compliance.
- JCPOA Commitments
- Not a treaty: no formal ratification by signatories;
- Considered a political commitment (“soft law”) based on mutual consent and reciprocity;
- Breach of JCPOA provisions alone does not automatically entail international legal responsibility unless it also violates the NPT or safeguards agreement.
IV. Why Iran Has Not Withdrawn from the NPT or Its Safeguards Obligations
Iran has frequently criticized Western sanctions and accused other countries of violating their NPT commitments. Nonetheless, it has never formally withdrawn from the NPT or its IAEA Safeguards Agreement. Reasons include:
- Legal legitimacy: Remaining in the NPT allows Iran to lawfully pursue peaceful nuclear technology under Article IV. Withdrawal would undermine its position as a compliant actor and expose it to immediate global backlash.
- Political optics: Iran uses its NPT membership to claim it does not seek nuclear weapons and to accuse others (notably Israel and the US) of nuclear double standards. Leaving the NPT would contradict its longstanding official narrative and isolate it diplomatically.
- Strategic ambiguity: Staying in the NPT allows Iran to develop nuclear capabilities up to the threshold of weaponization while avoiding outright violation. It maintains leverage in negotiations and deters adversaries from military escalation.
- International repercussions: A formal NPT withdrawal, as with North Korea in 2003, would trigger automatic suspension of IAEA verification, likely prompting UN sanctions, loss of support from Russia and China, and potential regional proliferation (e.g., Saudi Arabia, Egypt).
- Security calculus: Iran perceives that maintaining its NPT status is a better security strategy than open defiance. It allows Tehran to avoid preemptive attacks and continue its program under international observation.