The Joint Comprehensive Plan of Action (JCPOA), endorsed by UN Security Council Resolution 2231 (2015), represents a cornerstone of contemporary non-proliferation diplomacy. Recent threats by European JCPOA participants — notably France, the U.K., and Germany — to invoke the Resolution’s so-called “snapback” mechanism against Iran underscore a troubling dissonance between their stated commitment to a law-based international order and their apparent willingness to manipulate legal instruments for political ends. This article contends that such threats lack a sound basis in international law and risk undermining the authority of the Security Council.

An examination of the legal frameworks governing the JCPOA and Resolution 2231 reveals several critical flaws in Europe’s approach:

1) Purpose and scope of the snapback mechanism: The snapback procedure under Resolution 2231, paragraph 11, was designed as an ultima ratio to address unprovoked, material breaches of the JCPOA, not as a punitive measure against a party responding to prior violations. The United States’ withdrawal on May 8, 2018, and the subsequent re-imposition of sanctions breached Annex II’s sanctions relief obligations, fundamentally undermining the JCPOA’s object and purpose. Europe’s failure to ensure economic normalization, as mandated by Articles 26 and 29, compounded this erosion. Iran’s subsequent measures — e.g. exceeding enrichment limits — fall within Article 36’s remedial framework to compel compliance. As Iran did not initiate the breach, invoking snapback against it contravenes the mechanism’s intent and lacks legal grounding.

2) Legal status of the JCPOA: Claims that the JCPOA constitutes a non-binding political commitment rather than a binding instrument are untenable. Its structured obligations, compliance mechanisms, and incorporation into Resolution 2231 under Article 25 of the UN Charter confer binding force. The International Court of Justice (ICJ) jurisprudence affirms that agreements establishing clear duties and enforcement provisions are legally obligatory, irrespective of formal treaty status. Europe cannot selectively disclaim the JCPOA’s legal force to evade its obligations — or ignore Vienna Convention on the Law of Treaties (VCLT) Article 31’s canons of good-faith interpretation — while invoking its provisions to justify sanctions.

3) Threshold for significant non-performance: Paragraph 11 of Resolution 2231 requires a JCPOA participant to notify the Security Council of an issue it “believes constitutes significant non-performance.” Customary international law demands that such belief be held in good faith and meet a materiality threshold under VCLT Article 60. Iran’s actions, authorized as remedial measures under JCPOA Article 36, respond to prior breaches and align with the agreement’s object of ensuring reciprocal compliance. Assertions that Iran’s enrichment exceeds remedial scope ignore Article 36’s allowance for proportionate responses, which Iran’s actions — calibrated to compel compliance — satisfy (VCLT Art. 51). They do not constitute a material breach undermining the agreement’s purpose. Europe’s awareness of this context precludes a good-faith basis for invoking snapback, rendering the move legally defective.

4) Security Council consensus and legitimacy: Security Council resolutions derive their legitimacy from consensus among members, particularly the P5. Resolution 2231 was unanimously adopted, reflecting a shared commitment to the JCPOA as a balanced non-proliferation framework. Attempting to invoke snapback under questionable circumstances — without genuine consensus, particularly given Russia and China’s positions — would constitute an abuse of process. Any resolution reinstated under such conditions would lack credibility under Article 39 of the UN Charter, representing procedural manipulation rather than a genuine determination of a threat to international peace and security.

5) Lawfulness of Iran’s remedial measures: Iran’s suspension of certain commitments followed unsuccessful recourse to the JCPOA’s Article 36 dispute resolution process. This aligns with the customary principle of exceptio non adimpleti contractus, upheld in ICJ case law (e.g. Gabčíkovo-Nagymaros), permitting suspension of performance in response to a material breach. Estoppel further bars Europe from invoking snapback, as its own non-compliance with economic normalization obligations precludes a good-faith demand for Iranian adherence. International tribunals consistently affirm that a breaching party cannot enforce obligations it fails to fulfill.

6) Procedural safeguards and the clean hands doctrine: The JCPOA’s compulsory dispute settlement process (Article 36) imposes a critical constraint on Europe’s ability to trigger snapback. Before escalating to the Security Council, parties must exhaust a structured sequence: Joint Commission review, ministerial consultations, and advisory board referral (JCPOA, paras. 36–37). At this stage, Iran can lawfully condition its return to full compliance on Europe’s fulfillment of sanctions relief and economic normalization obligations (Articles 26, 29). This stance, rooted in the JCPOA’s reciprocal structure and customary principles of countermeasures (Gabčíkovo-Nagymaros, ICJ, 1997), precludes a finding of “significant non-performance” under Resolution 2231 unless Europe remedies its own breaches. The equitable doctrine of “clean hands” — enshrined in international jurisprudence (Chorzów Factory, PCIJ, 1927) — further bars Europe from advancing with “unclean hands” stemming from its non-compliance. Absent a good-faith effort to meet its commitments, Europe’s pursuit of snapback would reflect a clear disregard for the JCPOA’s procedural and equitable framework, rendering the mechanism practically and legally unattainable.

7) Conformity with UN Charter principles: Article 24(1) of the UN Charter mandates that Security Council actions align with the organization’s purposes, including the maintenance of peace and stability. Resolution 2231 endorses the JCPOA as a tool for non-proliferation and global security. Employing snapback to penalize Iran for enforcing compliance, rather than breaching obligations, distorts this objective and risks abusing Chapter VII powers. Such misuse threatens to erode the Council’s credibility as a neutral arbiter.

Europe’s contemplated invocation of snapback under these conditions constitutes a legally indefensible and diplomatically reckless maneuver. It contravenes the JCPOA’s framework, misapplies Resolution 2231, and disregards foundational principles of international law — good faith, reciprocity, and procedural fairness. The implications extend beyond this case: manipulating Security Council mechanisms risks weakening treaty enforcement and emboldening unilateralism, potentially destabilizing non-proliferation regimes. If Europe persists, it may undermine its normative influence in international law, ceding moral and legal authority to those who favor coercion over cooperation. Scholars and practitioners must scrutinize such actions not merely as policy missteps, but as challenges to the coherence of the global legal order itself. To safeguard that order, states should preemptively declare that they would not consider any resolution reinstated under these flawed conditions as valid or enforceable.

*Reza Nasri is a prominent international lawyer and foreign policy analyst. The views expressed in this article are his own.