Unilateral Snapback Collective Failure: The Security Council at a Crossroads
Unilateral Snapback Collective Failure: The Security Council at a Crossroads
By: Reza Nasri
International law expert – Foreign Policy analyst
By: Reza Nasri
International law expert – Foreign Policy analyst
Introduction
The United Nations Security Council (UNSC) serves as the principal organ responsible for maintaining international peace and security under the U.N. Charter. Established to prevent unilateral coercion and promote collective decision-making, the Council functions as the chief forum through which enforcement measures, including sanctions, are deliberated and enacted. This institutional design aims to ensure that responses to threats to peace are legitimate, multilateral, and consistent with international law.
Among the UNSC’s core responsibilities is the authorization and oversight of sanctions as a tool for conflict resolution and non-proliferation. The legal foundation for these actions is found in Chapter VII of the Charter, which empowers the Council to determine the existence of threats to peace and to decide on appropriate measures in response. Article 24(1) vests the Security Council with the “primary responsibility for the maintenance of international peace and security,” mandating that its decisions be taken on behalf of all U.N. Member States. This collective authority is further underscored by Article 39, which requires a Security Council determination of a “threat to the peace” before enforcement actions, such as sanctions, can be imposed or reimposed.
The principle of collective security is at the heart of the UNSC’s legitimacy. Decisions regarding sanctions—whether imposition, lifting, or reimposition—must be made through the Council’s established processes rather than by individual states acting unilaterally. This principle is highly relevant to debates surrounding the Joint Comprehensive Plan of Action (JCPOA) and its associated “snapback” mechanism under U.N. Security Council Resolution 2231. While Resolution 2231 introduced a novel system allowing for the automatic reimposition of sanctions upon notification by a JCPOA participant, its legal interpretation and application remain contentious, especially when invoked unilaterally and under procedurally flawed circumstances.
This article examines the Security Council’s role under the U.N. Charter in relation to international sanctions, with a focus on the JCPOA’s snapback provision. It analyzes the legal and procedural requirements for the reimposition of sanctions, the necessity of a Security Council determination under Article 39, and the implications of unilateral actions by individual states. The discussion highlights how unilateral attempts to trigger snapback without a contemporary Security Council consensus risk undermining the Council’s authority, contradicting the principles of collective security, and destabilizing diplomatic efforts. By evaluating the legal and political dimensions of this issue, the article underscores the need to maintain the Security Council’s role as the central arbiter of international peace and security.
Historical Lessons from the League of Nations
The League of Nations, predecessor to the United Nations, failed in its mission to maintain international peace and security largely because it lacked a robust, consensus-based mechanism for collective security. Its Council operated under a unanimity principle that often produced paralysis; each member—including potential aggressors—held a de facto veto power, preventing swift and decisive responses to blatant violations of international law.
These structural flaws were exposed during Japan’s invasion of Manchuria in 1931 and Italy’s invasion of Abyssinia in 1935. In both incidents, the League’s Council could not agree on enforcement measures, as major powers either blocked collective action or abstained, rendering any response ineffective. Additionally, the League’s Covenant did not provide a structured threat-assessment process: while Article 11 declared that any war or threat of war was a concern, it offered no clear procedures for collectively determining aggression or for imposing mandatory enforcement measures. This left the Council’s recommendations largely advisory and opened the door to unilateral measures that undermined the League’s legitimacy.
By contrast, the U.N. Security Council’s requirement under Article 39—that enforcement actions be contingent upon a collective determination of threat—was designed precisely to avoid these pitfalls. If the JCPOA snapback mechanism is invoked without such a determination, it risks recreating the League’s failures, undermining the collective security framework of the United Nations, and encouraging states to bypass established legal norms in favor of unilateral coercion. When enforcement lacks a binding, collectively agreed legal basis, states can selectively justify unilateral interventions, fracturing global confidence in the international legal order. Ultimately, the League’s collapse offers a cautionary tale: without a firm, consensus-driven process to assess threats and authorize enforcement, even well-intentioned institutions risk losing credibility and effectiveness.
The Security Council’s Role Under the U.N. Charter
- Primary Responsibility for International Peace and Security
The U.N. Charter designates the Security Council as the primary organ for maintaining international peace and security. Article 24(1) stipulates that U.N. Member States grant the Council this principal duty, with Article 24(2) noting that the Council must act in accordance with the U.N.’s Purposes and Principles. Among these is the maintenance of international peace and security through effective collective measures to address threats to peace.
Critically, Security Council decisions require nine affirmative votes, including the concurring or non-opposing votes of the permanent five members. This structure balances broad consensus with the realities of great power politics. Unilateral actions by individual states to impose or reimpose sanctions bypass this decision-making framework and raise questions under Article 24 about whether those states can truly claim to act “on behalf of” all U.N. Members. Scholars such as Bruno Simma emphasize that Council decisions under Chapter VII must adhere to the Charter’s principles—collective deliberation, proportionality, and legitimate authority—to preserve the Council’s legitimacy. The snapback mechanism, if invoked unilaterally by the E3, could contravene these principles by allowing a small subset of states to restore U.N. sanctions without the Council’s contemporaneous consent.
- Article 39 and the Requirement of a Threat Determination
Article 39 is pivotal: it instructs the Security Council to “determine the existence of any threat to the peace, breach of the peace, or act of aggression” before taking or recommending measures under Chapter VII. In practice, the Council normally makes this determination at the time it adopts a sanctions resolution. For instance, previous Iran-related sanctions resolutions (2006–2010) reflected an implicit or explicit finding that Iran’s nuclear activities constituted a threat to peace. When those sanctions were lifted in 2015 by Resolution 2231, it was premised on the understanding that the nuclear issue no longer posed the same level of threat, given the Council’s endorsement of the JCPOA.
Allowing the E3 to unilaterally “snap back” sanctions years later, absent a new Council finding under Article 39, effectively circumvents this requirement. The snapback process in Resolution 2231 attempts to pre-authorize sanctions reimposition upon a notification of “significant non-performance” by Iran, without any additional Council vote to confirm a renewed threat. If most Council members or key permanent members disagree that a Chapter VII-level threat exists at that moment, automatically restored sanctions lack a fresh legal basis under Article 39. Simply put, unilateral snapback usurps the Security Council’s exclusive authority to judge the existence of a threat to the peace, undermining the legitimacy and legality of any reimposed sanctions regime.
- The Purpose and Objectives of the Security Council
The U.N.’s purposes and principles also stress peaceful dispute resolution (Article 1(1)) and the avoidance of force or coercion, except where necessary to maintain peace. The JCPOA itself was achieved through pacific settlement, a solution hailed by the Council as fostering stability and confidence. Endorsing the JCPOA via Resolution 2231 reinforced the Council’s preference for diplomacy over confrontation. A snapback initiated by the E3 at this juncture could collapse the JCPOA—returning all U.N. sanctions and prompting Iran to cease compliance entirely. Such an outcome risks escalating the nuclear crisis, potentially pushing Iran toward withdrawal from the Non-Proliferation Treaty and spurring regional tensions.
From a teleological viewpoint, Resolution 2231’s intent was to enable a peaceful settlement, not facilitate renewed confrontation. The resolution specifically “urged full implementation of the JCPOA” and expressed the Council’s goal of concluding the matter satisfactorily. Using snapback to undermine the JCPOA would constitute an abuse of the resolution’s object and purpose, contrary to basic good-faith interpretation standards under the Vienna Convention on the Law of Treaties. Thus, an opportunistic invocation of snapback, especially driven by political pressures rather than genuine security threats, would contravene the principle of collective enforcement embedded in the U.N. Charter.
The JCPOA Snapback Mechanism Under UNSCR 2231
- The Design of the Snapback in Resolution 2231
The JCPOA’s dispute resolution and snapback mechanism is detailed in JCPOA provisions (notably Article 36) and implemented via Resolution 2231 (2015). Paragraphs 10–12 establish a procedure allowing a “JCPOA participant State” to trigger U.N. sanctions reimposition by notifying the Security Council of significant non-performance by Iran. Once triggered, there is a 30-day window during which the Council is supposed to adopt a resolution to continue sanctions relief; failing that, all previous sanctions on Iran automatically resume.
This approach inverts the normal Council practice, where sanctions require an affirmative vote to impose or maintain them. Under snapback, sanctions re-emerge by default unless actively blocked. The permanent members themselves accepted this arrangement, in part, to ensure that potential Iranian violations could not be shielded by any single veto. Although seemingly straightforward, this mechanism remains in tension with the Charter’s requirement that enforcement measures follow a fresh Article 39 determination. Resolution 2231 contemplates Council deliberation during the 30-day period, but because the notifying state can veto any resolution to continue relief, that deliberation may become moot.
- Limitations and Conditions on Snapback
Snapback is subject to procedural and substantive requirements. First, only a valid “JCPOA participant State” can initiate it. The 2020 U.S. attempt to trigger snapback after withdrawing from the JCPOA illustrated that states no longer participating in the deal lack standing to invoke its provisions. Second, the notion of “significant non-performance” by Iran must be grounded in fact and not used as a pretext for unilateral policy goals. Iran’s departures from the JCPOA have often been reactive, reversible steps taken under international monitoring, challenging arguments that these breaches alone justify permanent sanctions reimposition.
Additionally, the JCPOA prescribes dispute-resolution channels that must be exhausted before snapback is pursued. Invocation in bad faith—particularly if the complaining party itself has breached its obligations—would violate both the letter and spirit of the agreement, as well as the doctrine of clean hands in international law. In short, the snapback mechanism should not serve as an instrument of coercion but rather as a last resort to address an objectively serious violation.
- Snapback vs. Security Council Deliberation
The central legal question surrounding snapback is whether sanctions can be lawfully reimposed without a renewed Security Council determination under Article 39. Proponents of unilateral snapback argue that Resolution 2231 effectively pre-authorized the automatic restoration of sanctions upon notification by a JCPOA participant, making a new Council decision unnecessary. However, under the U.N. Charter’s framework, the Security Council is required to assess and confirm the existence of a threat each time Chapter VII enforcement measures are imposed or reimposed, ensuring that sanctions remain grounded in a contemporaneous determination of necessity.
The events of 2020 underscore the fundamental importance of Council endorsement in determining the validity of snapback. When the United States attempted to unilaterally invoke snapback despite having formally withdrawn from the JCPOA in May 2018, its claim was overwhelmingly rejected by the international community. The remaining JCPOA parties, including the E3 (France, Germany, and the UK), dismissed the U.S. position as legally untenable, emphasizing that Washington’s exit from the agreement stripped it of any standing to trigger snapback. This interpretation prevailed internationally, as 13 of the 15 Security Council members immediately rejected the U.S. notification, leading the Council’s President to declare that there was no consensus to proceed, thereby rendering the attempted snapback legally void.
This episode sets a critical precedent: strict compliance with procedural requirements—particularly the identity of the notifying party—is essential for any snapback attempt to be deemed valid. Unlike the U.S. in 2020, the E3 formally remain JCPOA participants, meaning they facially meet the “JCPOA participant” requirement under Resolution 2231. However, the manner and context of an invocation matter as much as legal standing. The broad rejection of the U.S. attempt suggests that snapback will not be internationally recognized if it is seen as procedurally flawed, politically motivated, or lacking substantial Council support. Even if the E3’s claim rests on stronger procedural footing than the U.S. case, strong opposition from Russia, China, and other Council members could still obstruct the practical enforcement of any reimposed sanctions. Without broad consensus, states may refuse to recognize the legitimacy of a restored sanctions regime.
Ultimately, the JCPOA snapback mechanism conflicts with standard Security Council practice, which typically requires a fresh threat determination and broad agreement before enforcement measures are reinstated. While Resolution 2231 establishes a pathway for snapback, its implementation must align with the Charter’s higher-order requirements, including collective authorization and procedural integrity. U.N. sanctions, by their nature, derive legitimacy from multilateral consensus—not unilateral assertions.
- Additional Procedural Flaws in a Potential E3 Snapback
Even if the E3 (France, Germany, and the UK) have formally remained participants in the JCPOA, their own alleged non-compliance with certain sanctions-relief obligations raises questions under the clean hands doctrine—a principle in international law holding that a party cannot seek relief if it is itself in breach of the agreement. If the E3’s insufficient efforts to facilitate Iran’s sanctions relief contributed to Iran’s reciprocal scaling back of its commitments, then the E3’s standing to accuse Iran of “significant non-performance” is severely weakened.
Moreover, Article 36 of the JCPOA sets out the dispute resolution process, stating:
“[…]If, after this process, the issue was not resolved, the complaining party could treat the unresolved issue as grounds to cease performing its commitments under this JCPOA in whole or in part and/or notify the UN Security Council that it believes the issue constitutes significant non-performance.” [Emphasis added]
Under this provision, a JCPOA participant may invoke the dispute resolution mechanism if it “believes” that another party is not meeting its commitments. However, good faith—a core principle of international law—demands that such a belief be genuine, reasonable, and not merely a pretext for politically motivated actions. If Iran’s reduction in compliance was itself a remedial measure responding to the E3’s (and previously the U.S.’s) failures to meet sanctions-relief obligations, then the E3’s assertion of “significant non-performance” lacks credibility under any objective standard. A party cannot legitimately cite Article 36 to penalize conduct it helped provoke. Consequently, an E3 snapback attempt without fully complying with their own JCPOA commitments risks being procedurally invalid, legally questionable, and inconsistent with the notion of clean hands.
Conclusion: Preserving Collective Security
The analysis underscores the complex legal and political tensions at play in applying the snapback mechanism under Resolution 2231. On one hand, the resolution establishes a swift path for reimposing sanctions in response to Iran’s serious non-compliance; on the other, the U.N. Charter’s foundational principles—particularly the requirement for a collective determination of threats under Chapter VII—demand a more measured, consensus-driven approach.
History demonstrates that when an international body fails to unify in its response to a perceived threat— as seen with the League of Nations— it paves the way for institutional failure and destabilizing unilateral actions, leading the devastating consequences. The Security Council was expressly designed to prevent such outcomes by ensuring that enforcement measures are grounded in a collective determination of threat. Invoking snapback unilaterally and under dubious procedural circumstances, particularly on an issue as sensitive as nuclear non-proliferation within the Middle East’s volatile security landscape, risks escalating regional tensions and undermining the very purpose of the Security Council.
At this juncture, a negotiated political solution, rather than the reckless instrumentalization of the Council, offers the most prudent path for addressing nuclear concerns while preserving the integrity of the international security framework.