In the continued fallout following the assassination of top Iranian nuclear scientist Mohsen Fakhrizadeh in Tehran in November, leading European powers issued a joint statement this week to urge Iran to keep its commitments to the 2015 nuclear deal. The warning, which followed a series of escalatory measures by the Persian Gulf state, sought to steer Iranian officials towards honoring the progress made in the Joint Comprehensive Plan of Action, or JCPOA. It comes as embattled European officials struggle to hold together the embers of the landmark deal after the withdrawal of the United States in 2018.

The statement by the so-called E3 countries, France, Germany, and the United Kingdom, emphasizes that the JCPOA “remains the best, and currently the only, way to monitor and constrain Iran’s nuclear program,” which has been the source of regional and international tension for decades. The deal, agreed upon in July 2015 by a coalition of powers known as the P5+1 (the five permanent nuclear powers plus Germany) and the European Union, established restrictions on Iranian nuclear proliferation in exchange for loosened economic sanctions. According to the U.S.-based Arms Control Association, these included a cap on uranium-235 enrichment levels at 3.67%, the prohibition of heavy-water reactors, and regular International Atomic Energy Agency (IAEA) inspection and monitoring of nuclear sites. By limiting Iran’s nuclear capabilities to exclusively peaceful means, the JCPOA sought to bring an end to the regional instability caused by potential Iranian proliferation, while eased sanctions among signatories on key sectors including oil and banking were designed to bring Iran to the negotiating table.

However, the withdrawal of the United States from the deal in May 2018 effectively put the agreement on ice. Dr. Ariane Tabatabai, a fellow at the Alliance for Securing Democracy at the German Marshall Fund of the United States, said that the withdrawal of the Trump administration was critical because it reinstated perhaps the most damaging of sanctions on Iran. Despite a European blocking statute, the U.S. decision left negotiators in Brussels with little leverage to hold Iran to its agreements. Since then, the country has gradually scaled back its commitments under the deal, including increasing regulated uranium stockpiles. Although President Hassan Rouhani has indicated that all measures are reversible with cooperation from even some of the P5+1 partners, skeptics in Tehran have challenged the urgency to re-establish partnership without an immediate commitment from President-elect Joe Biden’s administration.

The criticism of Iran’s actions is complicated further by the unseen consequences of the assassination of Mohsen Fakhrizadeh just outside the capital in November. Seen by some as the “father” of the Iranian nuclear program, Fakhrizadeh’s surprise murder has pushed tensions with Israel to dangerous highs, with Israeli Prime Minister Benjamin Netanyahu having previously identified the scientist as a key target in the region. Although implications on Iran’s nuclear development have yet to unfold, a bill passed by the Iranian parliament and fast-tracked into law against the wishes of President Rouhani last month forced European diplomats into their warning. According to Dr. Tabatabai, the legislation enables Iran to resume enrichment at 20%, a significant escalatory step, while also permitting the installation of new advanced centrifuges and heavy water reactors that are critical for the uranium enrichment needed to create nuclear weapons. Although the bill does not deny access to IAEA inspectors, it lays down a two-month timeframe for oil and banking-related economic relief before Iran will start to dial back compliance with monitoring elements that go beyond the safeguarding agreement.

In their statement on December 7th, the E3 countries were particularly vocal against the bill, which they said inhibits a return to the diplomatic discussions needed to keep the 2015 deal alive. “Iran’s recent announcement to the IAEA that it intends to install an additional three cascades of advanced centrifuges at the Fuel Enrichment Plant in Natanz is contrary to the JCPOA and deeply worrying,” noted the announcement, highlighting the concern for the international non-proliferation efforts that the deal set out to mandate.

The maintenance of nuclear peace in the Middle East comes at a pivotal time for stability in the region. The second assassination of a top Iranian figure in less than a year, following the U.S. drone killing of General Qasem Soleimani in January, has threatened to reignite tensions between Iran and its rivals including Israel and the West. To salvage the remnants of the JCPOA deal and keep peace alive, the E3 powers must consolidate their reaction to Iran’s latest infringement of the deal and work hard to bring the incoming Biden administration back onboard quickly, following his inauguration on January 20th. As shown by President Rouhani’s comments, consolidating a peaceful solution may still be possible even after the setbacks of the Trump administration.