What was the JCPOA and why did it collapse?

The Joint Comprehensive Plan of Action, signed in 2015, limited Iran's uranium enrichment to 3.67% purity, capped its stockpile at 300 kg, and required the conversion of its Fordow facility into a research center. In exchange, international sanctions were suspended. The deal collapsed after the Trump administration withdrew in May 2018, reimposing sanctions. Iran subsequently breached JCPOA limits, and by 2023 had enriched uranium to 60% purity and accumulated over 3,000 kg of enriched material.

Why does Iran insist on keeping enrichment capacity?

Iran argues that enrichment is a sovereign right guaranteed under the Nuclear Non-Proliferation Treaty and represents a technological achievement that cannot be reversed domestically or internationally. The IRGC and hardline political factions treat the enrichment program as a national security asset and a symbol of scientific independence. Any deal that requires Iran to permanently forgo domestic enrichment is considered politically toxic.

What would Iran need in return for a new deal?

Iranian negotiators have consistently demanded full lifting of all nuclear-related sanctions, guarantees that the U.S. would not withdraw again (which no U.S. president can legally provide), and removal of the IRGC from the State Department's Foreign Terrorist Organization list — a concession American negotiators have found politically difficult to make.

Diplomacy

What a Nuclear Deal Would Actually Require From Tehran

Reviving a nuclear agreement with Iran is not primarily a technical problem — it is a political one. What Western governments are actually demanding, and why Tehran finds the terms so difficult to accept, reveals the gap that has defeated diplomacy for years.

Cyrus Rahimi · March 5, 2025

The technical parameters of a nuclear agreement with Iran are not especially difficult to design. Diplomats and arms control experts have spent years refining the parameters that would extend Iran’s breakout time — the period needed to accumulate enough highly enriched uranium for a weapon — to a year or more. The documents exist. The formulas are understood. What has defeated diplomacy is not the technical problem but the political one: what, precisely, would Tehran have to give up, and why does that list remain politically impossible to accept?

The Enrichment Question

The central demand of any Western-backed nuclear deal is a significant rollback of Iran’s enrichment capacity. The original JCPOA of 2015 capped enrichment at 3.67% purity — well below weapons-grade — and required Iran to ship much of its stockpile out of the country. Iran accepted those terms because the alternative, continued sanctions pressure, was generating genuine economic pain.

Since the American withdrawal in 2018 and Iran’s subsequent decision to exceed JCPOA limits, the baseline for negotiations has shifted dramatically. Iran now enriches to 60% purity — a significant technical step beyond what any civilian nuclear program requires — and has accumulated a stockpile that, if further enriched, would be sufficient for multiple weapons. Returning to JCPOA-level restrictions would require shipping out or diluting material Iran has spent years and considerable political capital accumulating.

Iranian negotiators have consistently said they can accept temporary limits but not a permanent cap on enrichment capacity. The distinction matters: temporary limits can be presented domestically as tactical flexibility; permanent limits look like capitulation.

The Verification Architecture

The second major demand concerns inspections. The IAEA’s current access to Iranian nuclear facilities is limited. Iran suspended the Additional Protocol — the enhanced inspection regime it agreed to under the JCPOA — after the American withdrawal, and its cooperation with IAEA investigations into undeclared nuclear activities has been halting at best.

A new deal would require restoration of at least JCPOA-level monitoring and ideally enhanced access to facilities and supply chains. The IAEA has outstanding questions about three sites where uranium traces inconsistent with Iran’s declarations have been detected. Iran has refused to answer those questions satisfactorily, and Western governments have made clarifying those discrepancies a precondition for sanctions relief.

What Iran Needs in Return

From Tehran’s perspective, the economic relief promised under the original JCPOA never fully materialized. Even before the American withdrawal, European banks remained reluctant to clear transactions with Iran, fearing secondary sanctions. After the Trump administration’s “maximum pressure” campaign, Iran’s oil exports collapsed and inflation devastated the middle class.

Any new deal would need to offer sanctions relief that is immediate, comprehensive, and in some meaningful way guaranteed — a near-impossibility given the U.S. constitutional structure, which allows any future administration to withdraw from executive agreements. Iranian negotiators have asked for a congressional commitment; American negotiators cannot deliver one.

The IRGC Problem

Among the most contentious elements is the status of the IRGC’s Foreign Terrorist Organization designation. The Trump administration added the designation in 2019, and it has proven difficult to reverse domestically for any American president. Iran has treated removal of the designation as a threshold condition for serious talks. American and European officials have been unable to agree internally on whether to offer it.

The IRGC designation is not merely symbolic. It affects the legal exposure of any company or individual transacting with IRGC-affiliated entities — which, given the IRGC’s economic dominance, encompasses much of the Iranian economy. Without its removal, the sanctions relief offered under a new deal would be structurally incomplete.

The Gap That Remains

What a nuclear deal would actually require from Tehran is a sustained reduction in enrichment purity and stockpile, enhanced IAEA access including to sites with unexplained nuclear activity, and at least a rhetorical commitment to the principle that Iran will not build a nuclear weapon. What Tehran would need in exchange is reliable, durable, and comprehensive sanctions relief — something no American administration has demonstrated it can guarantee.

That gap has now persisted through multiple American administrations, two Iranian presidents, and one U.S. withdrawal from a deal that was working. The technical documents remain on the shelf. Whether the political will exists to close the distance is a question that belongs to leaders, not diplomats.

Frequently Asked Questions

What was the JCPOA and why did it collapse?: The Joint Comprehensive Plan of Action, signed in 2015, limited Iran's uranium enrichment to 3.67% purity, capped its stockpile at 300 kg, and required the conversion of its Fordow facility into a research center. In exchange, international sanctions were suspended. The deal collapsed after the Trump administration withdrew in May 2018, reimposing sanctions. Iran subsequently breached JCPOA limits, and by 2023 had enriched uranium to 60% purity and accumulated over 3,000 kg of enriched material.
Why does Iran insist on keeping enrichment capacity?: Iran argues that enrichment is a sovereign right guaranteed under the Nuclear Non-Proliferation Treaty and represents a technological achievement that cannot be reversed domestically or internationally. The IRGC and hardline political factions treat the enrichment program as a national security asset and a symbol of scientific independence. Any deal that requires Iran to permanently forgo domestic enrichment is considered politically toxic.
What would Iran need in return for a new deal?: Iranian negotiators have consistently demanded full lifting of all nuclear-related sanctions, guarantees that the U.S. would not withdraw again (which no U.S. president can legally provide), and removal of the IRGC from the State Department's Foreign Terrorist Organization list — a concession American negotiators have found politically difficult to make.