UN Sanctions on Iran: Back in Force or Gone for Good?

[Mohammadhossein Sedehi is a DPhil student in international law at the University of Oxford, St Edmund Hall]

Introduction

Almost 10 years ago, five permanent members of the UN Security Council (UNSC) and Germany, collectively known as the 5+1, reached a historic agreement with Iran regarding its nuclear program: the Joint Comprehensive Plan of Action (JCPOA). The agreement was endorsed by UNSC Resolution 2231, with the JCPOA itself annexed to the resolution. Fast forward to today, the JCPOA has failed to deliver on its once hopeful promises of peace and cooperation. In 2018, the United States unilaterally withdrew from the deal and initiated a campaign of maximum pressure against Iran. Almost a year later, Iran began reducing its nuclear commitments under the deal in response to US withdrawal. In June 2025, following two rounds of military exchanges, Israel launched a large-scale military operation against Iran, targeting Iranian nuclear scientists and facilities with the US later joining in attacking the Fordow nuclear site (legal analysis). As the final nail in the coffin for the JCPOA, on August 28 the E3 (UK, France and Germany) notified the UNSC of what they considered significant non-performance by Iran and triggered the so-called snapback mechanism which was intended to restore all the UN sanctions as they were in force prior to JCPOA and the adoption of resolution 2231 in 2015.

The E3 asserts that UN sanctions were re-imposed on 28 September 2025, following the expiration of the 30-day period set out in paragraph 11 of Resolution 2231. However, Russia and China, together with Iran, submitted a letter to the Secretary General and the President of the UNSC arguing that the E3’s invocation of the snapback mechanism was legally flawed and therefore void. According to them, the sanctions have not been re-imposed; rather, Resolution 2231 expired on 18 October 2025, resulting in the permanent termination of UN sanctions against Iran. This post explores the arguments put forward by each side regarding the current status of the UN sanctions on Iran and demonstrates how the opposition from two permanent members of the UNSC can cripple the implementation of sanctions and thus, practically render them partly ineffective.

Position of the E3

The Iranian sanctions regime is based on several UNSC resolutions, namely, resolutions 1696, 1737, 1747, 1803, 1835, and 1929. Under the JCPOA and Resolution 2231, Iran agreed to impose certain limitations on its nuclear program and to accept rigorous inspections in exchange for relief from UN sanctions. As part of this agreement, all the previous resolutions were terminated. However, resolution 2231 contains operative paragraph 11, which provides that any JCPOA participant may notify the UNSC if it believes that another participant is in significant non-performance of its obligations. Within 30 days of receiving this notification, the UNSC must adopt a resolution confirming the continuation of sanctions relief. If the Council fails to adopt such a resolution within 30 days, all the previous sanctions of the UNSC will automatically snap back into effect. This snapback mechanism was designed in a way to provide a reverse veto.  In that sense, once the notification of significant non-performance is made by a JCPOA participant, every member of the P5 will have the power to prevent any resolution being adopted (due to the veto power) and therefore restore UN sanctions.

On 28 August 2025, the E3 notified the UNSC of Iran’s significant non-performance of its JCPOA commitments and their intention to activate the snapback mechanism. On 28 September 2025, after the Council failed to adopt the draft resolutions proposed first by South Korea and later by Russia and China to extend the period, all resolutions previously terminated under Resolution 2231 were, according to the E3 and their allies, automatically restored.

Iran, Russia and China’s Position

However, Russia, China and Iran declared jointly that the recourse to snapback was not legally valid. They argued that resolution 2231 expired 10 years after its adoption, as foreseen in the resolution itself, and consequently, the sanctions have been permanently terminated. Both in the debates in the UNSC and also in joint letters (here and here), they advanced arguments to justify their conclusion, namely, E3’s lack of good faith in settling the dispute, procedural flaws in E3’s recourse to snapback mechanism and the clean hands doctrine These arguments will be assessed in turn.

Firstly, Iran argued that the E3 did not engage in good faith efforts to settle the dispute as is required by paragraph 37 of the JCPOA, which governs dispute settlement. During the UNSC session on 26 September 2025, the Iranian Foreign Minister stated that Iran had signed a cooperation agreement with the International Atomic Energy Agency (IAEA) on 9 September 2025 in Cairo, addressing E3’s concerns regarding IAEA’s inspections. Nevertheless, the E3 proceeded with activating the snapback. He further noted that he had reached an agreement with the French Foreign Minister two days before the session, but that agreement was disregarded due to US pressure. “The E3 and the United States acted in bad faith, claiming to support diplomacy while in effect blocking it,” stated by the Iranian Foreign Minister in the UNSC.

Secondly, Iran, Russia and China argued that the E3’s recourse to snapback was procedurally flawed due to a failure to exhaust the dispute settlement mechanism provided in paragraph 36 of JCPOA. While it is true that operative paragraph 11 of resolution 2231 only contains the notification to the UNSC and the 30-day period for the re-imposition of sanctions, the text of the JCPOA provides further nuances to the dispute settlement procedure. As the JCPOA is annexed to resolution 2231, operative paragraph 11 should be read in conjunction with the text of the JCPOA.

Under paragraph 36 of the JCPOA, if a participant state believes that another participant is not performing its obligations under the agreement, the complaining participant may refer the matter to the Joint Commission. If after 15 days the matter is not settled, then it will be considered by the Ministers of Foreign Affairs of the participant states. Should the matter remain unresolved after 15 days, the complaining participant could refer the dispute to an Advisory Board which is mandated to provide a non-binding opinion on the compliance issue within 15 days. If the issue still persists, the Joint Commission should consider the opinion of the Advisory Board within 5 days. If the matter is not resolved to the satisfaction of the complaining participant, only then would it constitute a basis for the notification of the UNSC of significant non-performance which is contained in paragraph 11 of resolution 2231.

Iran, Russia and China argued that the E3 did not have standing to invoke operative paragraph 11 of resolution 2231 since they had not exhausted the dispute settlement mechanism set out in paragraph 36 of the JCPOA. Since Resolution 2231 is indivisible, its provisions of the resolution should be read together with the text of the JCPOA which is annexed to the resolution. Accordingly, E3’s notification to the UNSC on 28 August 2025 is not considered a valid notification under paragraph 11 of resolution 2231. Interestingly, the E3 had previously made the exact same argument when it rejected Iran’s justification for reducing its JCPOA commitments in response to the US withdrawal from the deal, on the grounds that Iran had not exhausted the JCPOA dispute settlement mechanism. Although the E3 initiated the dispute settlement process in 2020, the Joint Commission was never convened and the subsequent steps under paragraph 36 of the JCPOA were not taken.

Finally, Iran, Russia and China argued that the E3 could not invoke the dispute settlement mechanism of an agreement they themselves constantly violated. This argument relates to the failure of the E3 to comply with its commitments under the JCPOA, namely, to take practical measures to make sanctions relief usable, protect lawful post-relief activity and proactively facilitate trade and finance. In essence, since Iran could not benefit from the JCPOA after US withdrawal and the E3 failed to uphold their commitments, clean hands doctrine implies that the violating party cannot rely on the rights arising from the agreement. In their joint letter, Iran, Russia, and China noted that the E3 had agreed to comply with US unilateral sanctions and had imposed their own restrictive measures, concluding that:

“a party which disowns or does not fulfil its own obligations cannot be recognized as retaining the rights which it claims to derive from the relationship”.

(ICJ Advisory Opinion on Namibia 1970, para. 91)

The clean hands doctrine, however, is not beyond contestation. ICJ has repeatedly rejected the applicability of the clean hands doctrine as a ground for inadmissibility of a claim at the preliminary objections stage (Jadhav, para 61; Certain Iranian Assets, para 122). That said, the Court has not precluded the possibility of arguing clean hands at the merits stage (Certain Iranian Assets, para 123). The Court in general has always approached the issue with caution and generally has not accepted the argument on that basis. Iran, Russia and China’s argument thus might be better framed as being based on the broader principle of reciprocity and good faith.

Additionally, some might argue that the JCPOA is a political agreement – not a treaty – and therefore, reciprocity and good faith will not apply since there is no binding legal obligation. However, it should be noted that even if JCPOA is characterized as a political agreement, its normative force cannot be dismissed. As stated by the ICJ, International law prescribes no particular form for assuming obligations and focuses on the parties’ intention (Nuclear Test case, para 43). JCPOA in its preamble, paragraph viii states “The E3/EU+3 and Iran commit to implement this JCPOA in good faith and in a constructive atmosphere, based on mutual respect, and to refrain from any action inconsistent with the letter, spirit and intent of this JCPOA that would undermine its successful implementation” (emphasis added). This indicates the intention of the parties to be bound and the quid pro quo nature of the JCPOA and show therefore, that the principles of reciprocity and good faith would have effect.

On the basis of the foregoing arguments, Iran, Russia and China claim that “the attempt by E3 to trigger the so-called snapback is, by default, legally and procedurally flawed,” and in the words of the Russian representative in the UNSC during the debate, “there has not been, nor will there be, a “snapback”. Any attempts to revive the anti-Iranian Council resolutions that were in force prior to 2015 are null and void.”

Practical Implications for the Sanctions Regime

But what are the practical implications of the disagreement of Russia and China, two permanent members of the UNSC, for the implementation of sanctions? Resolution 1737 established a sanctions committee (the Committee) to monitor the implementation of sanctions and carry out related tasks such as, listing and de-listing individuals and entities, considering requests for exemption, reviewing reports by states etc. The Committee is composed of all the members of the UNSC and is automatically established, pursuant to paragraph 18 of resolution 1737.

According to paragraphs 14 and 15 of the Committee’s Guidelines, the Committee makes decisions by consensus under a no-objection procedure. Under this procedure, the chair of the Committee proposes a decision and if within 10 days no objection is received, the decision is deemed adopted. Consequently, Russia and China, being permanent members of the Committee, can block any decision by lodging an objection. Even the agenda of any session must be adopted by consensus based on paragraph 11 of the Guidelines of the Committee. As a result, the Committee would be unable to designate any new entity, address the potential violation of sanctions by states and entities or effectively monitor the enforcement of sanctions.

Another relevant point concerns the Panel of Experts (established by resolution 1929), which was created to assist the Committee in carrying out its tasks, including gathering and analyzing information on the implementation and non-compliance of sanctions and providing recommendations to improve enforcement. The Panel’s mandate was renewed several times through subsequent UNSC resolutions; however, after the JCPOA, the Panel’s mandate was not renewed. Russia and China can block any attempt to re-establish the Panel, thereby further impeding the implementation and monitoring of the sanctions.

Although there has been no official press release by the UNSC regarding the reinstatement of sanctions, the website of the 1737 Sanctions Committee is now updated to indicate the reimposition of sanctions (in the section ‘Further information on measures’). Russia has objected to this issue in a letter addressed to the Secretary-General and requested the announcement be removed. Russia argues that there is not agreement within the Council as to the status of sanctions and the Secretariat, according to Article 100 of the Charter (Independence), should not take sides in this matter.

Conclusion

In conclusion, Western states maintain that the UN sanctions against Iran have been reinstated, while Russia, China and Iran contend otherwise. Beyond the legal arguments and their respective strengths, this post has sought to show how the implementation of the sanctions is affected by the opposition of two permanent members of the UNSC. Although any member state of the UN may now rely on UN sanctions to impose restrictive measures against Iran, the violation of these sanctions will go unaddressed as the Committee will be unable to act on them, which makes the overall effectiveness of the sanctions uncertain. Moreover, with the very existence of sanctions regime being under contestation, many states may also refrain from the implementation of the UN sanctions at all, relying on the arguments made above and the existing disagreement within the UNSC.