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Iran's nuclear program
Began 1957; secret sites exposed 2002; JCPOA 2015; UN snapback 2025· Issue or flashpoint
FactTreaties, membership, measured data, events.
Iran's decades-long nuclear effort, which it calls peaceful but which reached near-weapons-grade enrichment and became the trigger for two wars.
See it on the Geopolitics map →The picture
It began in 1957 under the Shah with US help. In 2002 exiles exposed secret enrichment and heavy-water sites. The 2015 JCPOA deal capped enrichment at 3.67% for sanctions relief; the US quit in 2018 and Iran later enriched to 60%, close to the roughly 90% used in bombs. By June 2025 it held about 440 kg of 60% uranium. Israeli and US strikes in 2025 and 2026 wrecked key sites, UN sanctions returned in September 2025, and the stockpile's whereabouts are uncertain.
Why it matters
A nuclear-armed Iran could set off a regional arms race, with Saudi Arabia vowing to match it; preventing that drove the 2025 and 2026 wars.
Key facts and numbers
IAEA inspection reports and board resolutions, including the September 2026 referral to the UN Security Council; the JCPOA text; satellite imagery; and US and Israeli intelligence statements.
What to watch
Disputed: whether Iran ever decided to build a bomb, where its 60% uranium is now, and how fast it could rebuild enrichment; IAEA access is limited.
Connections (3)
▸Twelve-Day War: Israel and the US strike Iran bombed sites of Iran's nuclear programFact
The relationship
Israel struck enrichment and conversion sites at Natanz and Isfahan from June 13, 2025 and killed leading nuclear scientists. On June 22 US B-2s dropped 30,000-pound bunker-busters on Fordow, buried inside a mountain, and on Natanz, while Tomahawks hit Isfahan. Iran then curbed cooperation with UN inspectors.
Since when and why
June 13–24, 2025: Israel's Operation Rising Lion and the US Operation Midnight Hammer, ordered by Netanyahu and Trump.
How we know
Satellite imagery, US and Israeli briefings, and IAEA reports confirming damage and loss of inspector access.
What to watch
Debated: whether the bombing set the program back for years or strengthened arguments in Tehran for building a bomb as the only sure deterrent.
▸Iran's nuclear program is a proliferation flashpoint in Nuclear weapons and proliferationWidely agreed
The relationship
Iran's 60% enrichment left it, by US and IAEA estimates, only weeks from bomb-grade fuel for several weapons. That threatened to make it a tenth nuclear-armed state and spur others: Saudi Arabia says it would match an Iranian bomb. It is also the main test of whether the NPT can stop a determined state.
Since when and why
IAEA reports of 60% enrichment from 2021; crises peaking in the June 2025 and February 2026 strikes; the IAEA board's referral to the UN Security Council, September 2026.
How solid?
IAEA quantitative reports, including the 440.9 kg stockpile figure, US intelligence assessments, and Crown Prince Mohammed bin Salman's public statements in 2018 and 2023.
What to watch
Disputed: US intelligence long judged Iran was not actively building a bomb; whether the strikes delayed or hastened a decision to seek one is debated.
▸Iran's nuclear program faces UN snapback sanctions from UN Security Council and the P5 vetoFact
The relationship
The 2015 nuclear deal was written into Security Council Resolution 2231, which lifted UN sanctions but let any party 'snap them back'. Britain, France and Germany triggered it in August 2025, saying Iran had breached the deal; the arms embargo, missile limits and asset freezes returned on September 27, 2025.
Since when and why
UN headquarters, New York; the European notice of August 28, 2025; a Russian–Chinese bid to delay failed 4–9 on September 26, 2025.
How we know
Resolution 2231's text, the European letter, Council voting records, and the IAEA board's September 2026 referral of Iran to the Council.
What to watch
Disputed: Russia, China and Iran call the snapback legally void and refuse to enforce it; how far other states comply is unclear.