Armed with a cartoon-style drawing of a bomb with a lit fuse, Binyamin Netanyahu took to the UN General Assembly podium in 2012 to try to convince the world of the threat posed by Iran’s nuclear programme.
The Israeli prime minister said the Islamic republic was enriching uranium at such a pace that it was on track to be able to produce sufficient fissile material for a nuclear weapon within months. With a marker pen, he drew a red line across the bomb to highlight the stage of the process where Iran had to be stopped, warning that “the future of the world” was at stake.
Fast-forward 13 years, and Netanyahu says Tehran has moved far beyond his red line by establishing a programme to develop nuclear weapons and is using that as his prime pretext for Israel’s devastating assault on Iran.
“In recent months, Iran has taken steps that it has never taken before – steps to weaponise this enriched uranium,” the prime minister said as the first Israeli bombs fell in the early hours of Friday.
But experts say that while Iran has been dramatically increasing its stockpile of uranium enriched to close to weapons-grade, there is no evidence it has decided to build a nuclear bomb.
“Netanyahu is always keen on dangling evidence in front of cameras, whether it’s nuclear secrets or pieces of Iranian drones,” said Ali Vaez, an Iran expert at Crisis Group. “But he offered no such evidence for that claim.”
US intelligence director Tulsi Gabbard told the US Congress in March that America’s intelligence community continued to assess that Iran was not building a nuclear weapon. The International Atomic Energy Agency (IAEA), which has inspectors in Iran who frequently visited the republic’s two main enrichment facilities at Natanz and Fordow, has also found no evidence to suggest the Islamic regime is developing a weapons programme.
Experts have, however, warned that Iran’s recent advances mean it has become a “threshold state” – a nation with technical expertise and capacity to weaponise its nuclear programme if it chooses.
Days before Israel launched its assault, the IAEA’s board for the first time in two decades passed a resolution saying Iran was in breach of its non-proliferation obligations.
Iran always insists its nuclear programme – initially developed by the last Shah with US assistance – is for peaceful civilian purposes.
But according to US intelligence assessments, Iran had begun initial work on a weapons programme more than two decades ago. Back then, it was still in the early stages of uranium enrichment, and the programme was halted in 2003, according to the assessments.
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A decade later, Iran began talks with the Barack Obama administration that culminated in a landmark 2015 accord signed with the US and other world powers. The agreement, implemented in January 2016, severely limited Iran’s nuclear activity, with a strict IAEA monitoring mechanism, in return for sanctions relief.
Iran was complying with the deal, which limited its uranium enrichment to 3.67 per cent and capped its stockpile of the fissile material at 300kg, with any excess shipped offshore.
But after US president Donald Trump abandoned the deal in 2018 and imposed sanctions on the republic, Tehran responded by increasing its activity, developing and installing thousands of far more advanced centrifuges that it is using to produce highly enriched uranium.
For four years, it has been enriching uranium to 60 per cent – its highest-ever level and a short step away from the 90 per cent required for a nuclear weapon.
In May, an IAEA report said Iran’s stockpile of 60 per cent enriched uranium had swelled to more than 400kg – enough fissile material for about 10 weapons if further enriched to 90 per cent – while its total stockpile of enriched uranium exceeded 8,400kg.
Tehran had for more than a year reached “near-zero breakout time”, giving it the capacity to produce sufficient fissile material required for several nuclear bombs within days, said Kelsey Davenport of the Arms Control Association. But it would still need to develop the technology to build weapons.
“The actual weaponisation process, that’s more challenging to accurately estimate. But it likely would have taken months, possibly up to a year, to convert weapons-grade uranium to fit it with an explosive package, then actually be able to deliver it via a missile,” Davenport said. “So there was no imminent threat of a nuclear bomb.”
The IAEA still has inspectors in the republic, but their access has been restricted after Tehran reduced co-operation with the UN nuclear watchdog. Israel, which is the Middle East’s only nuclear-armed state although it does not admit to its programme, has bombed Natanz. Iran says it also targeted Fordow.
Experts said there was a risk Tehran had secretly set up advanced centrifuges at facilities not monitored by the IAEA, where scientists could raise some of its stocks of highly enriched uranium to weapons-grade.
“Iran has produced thousands of advanced centrifuges and the IAEA has no idea where they all are,” said Vaez. “So there is a real possibility that Iran has, as part of its contingency plans, constructed clandestine facilities”.
In April, Ali Shamkhani, an adviser to supreme leader Ayatollah Ali Khamenei, said that if the republic faced continued external threats, it could take “deterrent measures”, including expelling the IAEA.
Shamkhani, who was seriously wounded in Israel’s first wave of strikes on Friday, which killed at least 10 nuclear scientists, added that Tehran could also transfer enriched material “to safe and undisclosed locations”.
Davenport said any secret facility would be more difficult to detect and could enrich material to weapons-grade “very quickly”, adding: “It would only have to remain illicit for weeks.”
Over the past year, as hostilities between Israel and Iran ratcheted up, Iranian officials have also issued ambiguous warnings about the possibility of changing Tehran’s nuclear doctrine.
“In the past year, we’ve seen an erosion of a decades-long taboo in Iran on discussing nuclear weapons in public, likely emboldening nuclear weapons advocates within Iran’s decision-making apparatus,” Gabbard told Congress in March.
Still, the IAEA said in a report last month it had “no credible indications of an ongoing, undeclared structured nuclear programme” and noted “the statements of the highest officials in Iran that the use of nuclear weapons is incompatible with Islamic law”.
Khamenei’s calculations could change, however, if the regime believes it now faces an existential threat and needs nuclear weapons to restore deterrence. And Israel’s strikes mean IAEA inspectors are unable to visit Natanz and Fordow, leaving the world blind to Iran’s activities for as long as Israeli bombing continues.
“The attacks will drive further discussion about the security value of nuclear weapons,” said Davenport. “My more immediate concern is that, in the absence of regular inspections, given the chaos that’s been caused in the strikes, the damage at the facilities, did Iran move any of its 60 per cent enriched uranium?”
Vaez believed the regime would still be cautious, saying Iran was “in a weak spot and doesn’t want to make a bad situation worse by bringing the US in”.
But he added that once the dust settled, Iran could feel the need to restore “leverage” ahead of any future talks with the US, including possibly withdrawing from the international nuclear non-proliferation treaty.
“Only then, I think we would hear Iran declaring its intention to change its nuclear doctrine. Israel has diminished Iran’s nuclear leverage, they would have to regain some,” Vaez said. “But we’re not there yet.”
Davenport said one thing Israel could not do was “bomb away the knowledge”.
“So Iran can rebuild and they can rebuild more quickly now,” she said.
– Copyright The Financial Times Limited 2025
