The Iran Nuclear Deal That Could Have Prevented This War — and Why It Collapsed

The JCPOA nuclear deal could have prevented the 2026 Iran war. Here is the history of why it collapsed and who bears responsibility for the outcome we now have.

The Joint Comprehensive Plan of Action — the JCPOA, or Iran nuclear deal — was implemented in January 2016 after two years of intensive multilateral negotiations involving Iran, the United States, the United Kingdom, France, Germany, Russia, and China. It was, by the assessment of most nuclear proliferation experts, the most comprehensive verified constraint on a nuclear programme that has ever been negotiated with a state that was actively developing nuclear weapons-relevant capability.

The specific deal required Iran to: reduce its uranium enrichment to 3.67 percent purity (far below weapons-grade); significantly reduce its centrifuge count; ship approximately 98 percent of its enriched uranium stockpile out of the country; disable the Arak heavy water reactor; and accept the most intrusive international inspection regime ever applied to a sovereign state's nuclear programme. In exchange, Iran received relief from nuclear-related sanctions that had been devastating its economy.

Trump withdrew the US from the JCPOA in May 2018, citing the deal's failure to address Iran's ballistic missile programme and its regional proxy activities — concerns that were legitimate but that addressed issues the JCPOA was never designed to cover. The withdrawal triggered a sequence: Iran initially maintained compliance while waiting for European partners to deliver the economic benefits the deal promised; European companies, unable to face US secondary sanctions by continuing Iran business, withdrew; Iran lost the economic benefit; Iran began progressively violating the deal's technical constraints; by 2021, Iran's nuclear programme had advanced further than it was when the deal was signed.

The Biden administration's attempts to restore the deal in 2021-2022 failed to reach conclusion before the political windows closed on both sides. The nuclear programme that the 2026 US-Israeli campaign is trying to destroy through military strikes is the nuclear programme that the JCPOA constrained for three years and whose subsequent development was partly a consequence of the deal's collapse.

The history does not assign blame cleanly. Multiple parties made decisions whose combined effect produced the current war. It does establish that a functioning diplomatic alternative existed and was abandoned.