With the world's attention focused on the wars in Gaza and Ukraine, Iran has come closer than ever to the ability to build multiple nuclear weapons, dramatically increasing the rate in recent weeks of producing nuclear fuel in facilities buried deep enough to be impervious to bunker buster bombs.
The rapid technological improvement is occurring in tandem with another disturbing change: For the first time, elements of Iran's ruling elite are abandoning its decades-old insistence that the country's nuclear program is entirely peaceful. Instead, they are openly embracing the logic of possessing nuclear weapons, arguing that recent missile attacks with Israel highlight the need for a much stronger deterrent.
Interviews with a dozen U.S., European, Iranian and Israeli officials, as well as outside experts, make clear the cumulative impact of this increase: Iran is moving closer to building a nuclear weapon without crossing the line, solidifying its role as a threshold nuclear power.
U.S. officials are divided on whether Iran is preparing to move to a final step or whether it will decide it would be safer and more effective to remain on the edge of nuclear weapons capability without openly abandoning its final obligations as a signatory to the Nuclear Non-Proliferation Treaty.
Most of the officials spoke on condition of anonymity because much of what is discussed about Iran's nuclear program is highly sensitive, ranging from assessments of its current status to covert efforts to prevent or slow its nuclear program.
They also warned that while Iran can now produce fuel for three or more bombs within a few days or weeks, it would still take a significant amount of time, perhaps 18 months, to process the fuel into warheads suitable for missiles like the one fired at Israel in April.
But Iran's nuclear expansion comes at a most delicate time.
Iran is keenly aware that the United States is determined to avoid an escalation of the Middle East conflict, and back-channel messages between Washington and Tehran underscore the dangers. One senior administration official said Iran itself knows how much it would cost if the war escalated.
But as one European diplomat involved in talks with Tehran noted, if Iran had been enriching uranium at its current levels several years ago – when the region was not such a flashpoint – Israel would almost certainly have considered the military option of attacking Iranian nuclear facilities.
Israeli Prime Minister Benjamin Netanyahu, who has come close to ordering such action on several occasions in the past, has been so preoccupied with the war with Hamas in Gaza and the risk of it escalating into an all-out conflict with Hezbollah on the Lebanese border that he has said little about Iran's recent military buildup, but there are signs from Israeli officials that they are taking renewed notice of Iran's recent advances.
They are also noting a shift in how Iran has spoken out about its long-standing nuclear program, which Israel has tried to thwart in recent years, sometimes with active U.S. involvement.
As Iranians prepare to vote on Friday to choose a successor to President Ebrahim Raisi, who died last month in a helicopter crash along with his foreign minister, Iranian officials are backtracking on boilerplate assurances that Iran's nuclear program has only peaceful uses in mind. One official close to Iran's supreme leader recently declared that Iran would “rethink its nuclear policy” if it faced an existential threat.
Israeli Defense Minister Yoav Gallant raised the issue of Iran's nuclear buildup in meetings this week with Secretary of State Antony J. Blinken, Secretary of Defense Lloyd J. Austin and Director of the Central Intelligence Agency William J. Burns, according to people familiar with the talks.
In April, Iran fired hundreds of missiles and drones at Israel, most of which were intercepted by Israel. But the attack, carried out in retaliation for an Israeli attack on the Iranian embassy compound in Syria that killed several Iranian military commanders, was a serious escalation. U.S. officials and outside experts concluded that the experience likely strengthened Iran's sense that it needed a stronger deterrent.
“Iran is sending a clear message that if the pressure of sanctions continues, if the assassinations of Iranian generals continue, if Washington or Israel decides to tighten the screws, they will break all chains,” said Hossein Alizadeh, a former Iranian diplomat who defected in 2010 and now lives in Britain.
According to its own estimates based on production statistics from the International Atomic Energy Agency, which still has limited access to Iran's facilities, Iran currently has enough enriched uranium to 60 percent purity to make at least three weapons, which can be converted into bomb-grade fuel within days or weeks.
Once Iran finishes installing the new centrifuges at its Fordow underground facility, it should be able to double its stockpile within a few weeks to months, nuclear expert David Albright said in an interview.
It will still be more than a year before the weapons are actually produced, but the question is whether US and Israeli intelligence agencies will be able to detect and thwart the effort.
The United States, Germany, Britain and France underscored the dangers in statements issued on Monday.
“Iran has increased its stockpile of highly enriched uranium to levels unprecedented for a country without a nuclear weapons program,” the two countries said, adding that “such activities have no civilian justification.”
The facility was left untouched and the deal abandoned.
The last time Washington felt it was facing a real nuclear crisis with Iran was in 2013, when President Barack Obama dispatched Burns, then a senior State Department official, and Jake Sullivan, then Vice President Joseph R. Biden Jr.'s national security adviser, to explore a possible deal with Iran's new President, Hassan Rouhani.
Messrs. Burns and Sullivan now hold very different roles but both played key roles in decisions about responding to Iran's expanding nuclear capability. They worked together to hammer out a six-month deal to curb Iran's nuclear program in exchange for billions of dollars in sanctions relief. Intense, on-and-off negotiations toward a permanent agreement followed, which was forged in mid-2015.
Under those terms, 97 percent of Iran's nuclear fuel was shipped out of the country and given to Russia, which at the time was working with the United States, the European Union, Britain, France, Germany and China to prevent Iran from acquiring a nuclear weapon.
But as negotiators at the time acknowledged, the agreement had weaknesses.
Iran resisted U.S. and European demands to dismantle it, arguing it needed to keep its main enrichment facilities, so the Fordow underground site remained intact and produced non-nuclear material — a concession the chief U.S. negotiator at the time called a “bitter pill.”
The main enrichment facility at Natanz was similarly destroyed, as it was much closer to the surface and easier to destroy. (Iran is currently building a deep underground facility at Natanz, but U.S. intelligence estimates it will take several years to complete.)
The U.S. and Israeli air forces have frequently trained to bomb Fordow, even building a mock base in the Nevada desert, but military officials say reaching that deep would require multiple, precise strikes by America's largest “bunker busters.”
Despite Republicans in Congress railing against the nuclear deal nine years ago, Iran initially stuck to its terms, limiting its production of nuclear fuel to a negligible amount. IAEA inspectors came and went regularly, and the agency's cameras monitored Iran's fuel stores around the clock, even as there was debate over reconstructing Iran's past activities.
And largely hidden from inspectors, Iran has been struggling for years to develop new IR-6 centrifuges that can produce fuel much faster than the older IR-1s, preparing for the day when it can install the new machines under the agreement's provisions.
President Donald J. Trump then abandoned the 2015 agreement, arguing that the reimposition of sanctions would topple the Iranian regime and predicting that Iran would beg for a new deal.
Trump was wrong on both counts. Iran slowly began to reopen its nuclear facilities. They removed some of the cameras and closed off some of the inspectors. And they began enriching to 60 percent purity, putting Iran much closer to bomb fuel than it was 11 years ago, when Burns and Sullivan were sent to negotiate secretly.
Efforts by the Biden administration to reconstruct key elements of the nuclear deal have collapsed in 2022. IAEA Director General Rafael Grossi said after a recent visit to Tehran that the 2015 nuclear deal, from which Trump withdrew, is now dead.
“Nobody applies it, nobody follows it,” he told a Russian newspaper recently. “There were attempts to revive it here in Vienna, but unfortunately, for reasons I don't know, it failed, even though it was relatively close to success.”
Denial of Weapons Programs Begins to Collapse
Iran has maintained that it cannot build or use nuclear weapons under a 2003 “fatwa,” or religious edict, issued by the country's supreme leader, Ayatollah Ali Khamenei. It maintains that the fatwa remains valid even after Israel seized and released a trove of Iranian documents that reveal the country is seeking to design nuclear weapons.
U.S. officials say there is no evidence of any ongoing efforts to weaponize Iran's weapons-grade uranium, while Israel alleges such efforts are underway under the guise of university research.
For Iran, the risk of moving towards nuclear weapons is high. Although Iran has removed or disabled some of the IAEA cameras, it is clear that the program is deeply penetrated by Israeli, US and British intelligence.
The cat-and-mouse game between inspectors and Israeli and Western spies has been going on for years, but the recent nuclear escalation can be traced back to missile launches in April that brought Iran and Israel to the brink of war.
Soon after, three senior officials with ties to Khamenei began declaring that Iran's non-weapon policy could be overturned if the country faced an existential threat. (Shiite Islam allows clerical scholars to overturn edicts and fatwas to reflect the demands of the times.)
The officials are Kamal Kharraj, a foreign policy adviser to Khamenei and former foreign minister; Abbas Araghchi, a prominent diplomat who served as deputy foreign minister and nuclear negotiator in the 2015 nuclear deal; and Gen. Ahmad Haq Taleb of the Revolutionary Guards, commander of protection and defense of Iran's nuclear facilities.
In a speech in mid-April, General Haq Talab said that if Israel threatened Iran's nuclear facilities, “it is quite possible that Iran will reconsider its nuclear doctrine and policies and reverse its previously stated positions.”
A few weeks later, Kharrazi told Al Jazeera that Iran has the capability to build a nuclear bomb but has not decided to do so.
“If Iran's existence is threatened, we will have no choice but to change our nuclear policy,” he said.
And in late May, Araghchi told a conference in Doha, Qatar, that the Israeli attack “could force other countries to rethink their security calculations and nuclear postures.”
The comments appeared coordinated, or at least reflected growing debate within the Iranian establishment about whether the time had come to weaponize the nuclear program and build a bomb, according to four Iranian officials, including a diplomat and an Islamic Revolutionary Guards officer, all of whom were aware of ongoing strategic discussions.
While the conflict remains intense, “at this point, given all the threats we face, many Iranians are beginning to believe and speak out that building a nuclear deterrent is not just a military strategy,” said Mehdi Chadeghanipour, a former adviser to former President Mahmoud Ahmadinejad. “It's just common sense.”