Does Europe have the legal standing to trigger dispute mechanisms against Iran?

Back in 2015, Iran struck a landmark deal with the P5+1 — the United States, the United Kingdom, France, Russia, China, and Germany — known as the Joint Comprehensive Plan of Action (JCPOA). The agreement was crafted to put strict limits on Iran’s nuclear program in return for lifting crippling economic sanctions. Among its provisions was a carefully designed dispute resolution process, including what’s called the “snapback mechanism,” allowing any party to reimpose UN Security Council sanctions if Iran significantly breached the deal. But Europe’s recent moves have thrown its own standing into question. In particular, the UK, France, and Germany — often referred to collectively as the E3 — have openly backed Israeli military strikes on Iranian nuclear sites. That support directly clashes with the JCPOA’s emphasis on resolving disputes peacefully. This paper argues that by endorsing these attacks, European powers have undercut their own legal basis to invoke the snapback, with serious ramifications for international law.

The JCPOA and its snapback provision: A quick refresher

At its core, the JCPOA was built to keep Iran from developing nuclear weapons. It imposed tight restrictions on Tehran’s nuclear activities: uranium enrichment capped at 3.67%, a major cut to its stockpile of enriched uranium, and a redesign of the heavy water reactor at Arak. In exchange, Iran would enjoy relief from international sanctions.

To ensure disputes didn’t spiral out of control, the deal included a multi-layered process spelled out in Section III, paragraph A. It started with direct talks, moved to a Joint Commission made up of all signatories, and if needed, escalated to the UN Security Council.

The snapback mechanism sat at the end of this process. If Iran seriously failed to hold up its end, any party could push to restore UN sanctions. But this tool wasn’t meant to be wielded lightly. The whole dispute process rested on principles of good faith and peaceful problem-solving. The JCPOA’s preamble laid this out clearly, invoking mutual respect and the UN Charter’s commitment to settling disputes without resorting to force. When a party acts against these values, it jeopardizes its own legal footing to enforce the deal.

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Europe’s support for Israeli strikes on Iran

There’s ample evidence showing that European countries, especially the E3, supported Israel’s strikes on Iran’s nuclear facilities in June 2025. On June 15, for instance, Ynet News reported that the UK, France, and Germany had all spoken up for Israel’s “right to defend itself” from what they characterized as Iran’s nuclear threat. This position isn’t new — it reflects a long pattern of European alignment with Israel on concerns over Iran, as well as a deliberate distinction in their minds between Iran’s nuclear ambitions and the Palestinian issue.

Just a day earlier, on June 14, Le Monde highlighted how France, Britain, and Germany, responding to Israel’s operation on June 13, reaffirmed Israel’s right to self-defense. German Chancellor Friedrich Merz bluntly stated that Israel was “doing the dirty work for all of us,” while French President Emmanuel Macron, despite calling for dialogue, backed Israel’s security stance. Then on July 1, the Clingendael Institute reported that European Commission President Ursula von der Leyen branded Iran the chief source of regional instability and endorsed Israel’s right to protect itself.

Germany went further than most. In June 2025, Chancellor Merz not only declared support for Israel’s actions as a boost to regional security, but also called Israel’s cross-border attacks on Iranian territory a legitimate act of self-defense.

Undermining the JCPOA’s core principles

By siding with strikes on Iran’s nuclear facilities — which are under the monitoring of the International Atomic Energy Agency — European powers are stepping squarely outside the spirit and the letter of the JCPOA. The deal was explicit: disputes over Iran’s nuclear program were to be settled through diplomacy, not force. And under Article 2(4) of the UN Charter, using or even threatening force against another state’s territorial integrity is banned, unless it’s in genuine self-defense or approved by the Security Council. Israel’s strikes lacked that UN authorization, classifying them as acts of aggression, and Europe’s support drags them into complicity under international law.

The snapback wasn’t designed as a hammer to be used after parties abandon dialogue and endorse military shortcuts. By cheering on Israeli attacks, the E3 have shown they’re willing to sidestep diplomatic avenues in favor of force. That decision severely undermines their neutrality as parties to the JCPOA. It also violates the principles of good faith and peaceful dispute resolution that give them the legal right to trigger the snapback in the first place.

Iran’s record of compliance under pressure

Even after the U.S. pulled out of the deal in 2018 and slapped tough sanctions back on Iran, Tehran largely stuck to its commitments for quite some time. The IAEA repeatedly confirmed that Iran’s nuclear activities stayed within JCPOA limits until tensions spiked recently.

All the while, Europe struggled — and often failed — to deliver the economic benefits it promised, like making financial transactions possible or getting the INSTEX mechanism running to keep trade alive.

More troubling, Europe didn’t just fall short on economics. It also offered no meaningful security guarantees to shield Iran from external attacks by Israel or the U.S. Worse yet, it didn’t even maintain neutrality, openly throwing its weight behind the side carrying out strikes on Iranian soil. This track record highlights Europe’s lack of commitment to both the JCPOA’s spirit and its actual text. Meanwhile, Iran’s efforts to keep the agreement afloat under enormous pressure underscore its own commitment to diplomacy.

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Legal and international fallout

Europe’s backing of Israeli attacks has weighty consequences, not just for the JCPOA but for the broader structure of international law. The principle of pacta sunt servanda — that agreements must be honored — is foundational in global relations. When parties start openly violating an agreement’s key principles, they lose the moral and legal ground to enforce its terms. By supporting Israel’s strikes, which break Article 2(4) of the UN Charter and Article 56 of the Additional Protocol to the Geneva Conventions (which bars attacks on nuclear installations), Europe effectively strips itself of the standing needed to trigger the snapback.

Adding to this, Europe’s double standard is glaring. It condemns Russian aggression in Ukraine while at the same time backing similar moves by Israel against Iran. That inconsistency erodes Europe’s credibility as a defender of international norms, weakening trust not just in its role as a mediator, but also in the legal order it claims to uphold. The fallout goes far beyond Iran, risking greater regional and global instability.

Europe’s — particularly the E3’s — open support for Israeli military strikes on Iran’s nuclear facilities has deeply undercut their legal position to activate the JCPOA’s snapback mechanism. By endorsing the illegal use of force, they’ve run roughshod over the principles of peaceful conflict resolution and good faith that lie at the heart of the deal. Meanwhile, Iran, under relentless economic and security pressures, has made repeated efforts to stick to its side of the bargain, even as Europe fell short on delivering promised economic benefits or any credible security guarantees. This imbalance makes it essential to reassess Europe’s role in the JCPOA and its actual commitment to international law. Until Europe realigns its actions with the deal’s spirit and letter, its legitimacy to invoke enforcement tools like the snapback will remain highly suspect. That doesn’t just put the future of the JCPOA in jeopardy — it shakes broader confidence in the rule-based international system itself.

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The views expressed in this article belong to the author and do not necessarily reflect the editorial policy of Middle East Monitor.