The United States and its allies have few routes left to rein in Iran's nuclear work with prospects for talks long buried and tougher actions against Tehran running the risk of stoking tensions in a region already enflamed by the Gaza war.
With a U.S. election next year limiting Washington's room for manoeuvre, four serving and three former diplomats painted a bleak picture of efforts to curb Iran's nuclear programme, which according to U.N. nuclear watchdog reports continues to advance.
The diplomats spoke to Reuters on condition of anonymity.
According to one of the two confidential reports by the International Atomic Energy Agency and seen by Reuters, Iran now has enough uranium enriched up to 60% purity - close to weapons-grade and a level Western powers say has no civilian use - to make three bombs.
The stockpile continues to grow, the reports say, even though Iran has consistently denied wanting nuclear arms.
Having failed to revive a nuclear deal between Iran and world powers that was abandoned by former U.S. President Donald Trump in 2018, President Joe Biden has no room for now even to consider a more informal "understanding" to curb Iran's nuclear work with a regional conflict raging and tension spiralling.
"There is a sort of paralysis, especially among the Americans ... because they don't want to add fuel to the fire," said a senior European diplomat.
Any negotiations to reach an "understanding" with Iran would have entailed Washington offering concessions - such as easing its tough sanctions regime on Tehran - in return for Iranian constraint.
Such a move now looks inconceivable after Iran-backed Palestinian group Hamas launched its devastating attack on Oct. 7 on U.S. ally Israel. Since then, Iran's regional proxy militias have launched dozens of attacks on U.S. and coalition troops in Iraq and Syria, according to the Pentagon.
At home, the Biden administration is constrained by U.S. presidential elections now just a year away. Trump, who at the moment looks most likely to be Biden's opponent, could seize on any engagement with Tehran and portray it as weakness.
"In the current environment, it is simply not politically feasible to seek an accommodation with Iran on the nuclear issue," said Robert Einhorn, a former U.S. State Department official.
"The political debate is really not going to be about negotiating with Iran, it's going to be about confronting Iran," he said.
IRAN STONEWALLING IAEA
Washington has deployed two aircraft carriers to the region and warplanes to the eastern Mediterranean, partly as a warning to Tehran. But U.S. officials have also made clear they do not want an escalation, urging Iran-backed militias to stand down.
Washington and its French, British and German allies - which were among the parties to the 2015 nuclear deal - will now focus on next week's IAEA Board of Governors meeting.
This week's IAEA reports showed Iran was making steady nuclear progress and indicated that Tehran continued to stonewall the agency in monitoring its work.
A deal in March to re-install monitoring equipment including surveillance cameras, which were removed last year at Iran's behest, has only partially been honoured.
Tehran's "de-designation" in September of some of the agency's most experienced inspectors - a move that effectively bars them from working in Iran - has also exasperated the IAEA.
Western powers in September had threatened to pass a binding resolution ordering Iran to reverse course - one of the strongest sanctions in the IAEA board's armoury.
Four diplomats said a resolution was now unlikely because it was imperative to avoid a diplomatic and nuclear escalation with Iran while attention is focused on Israel's conflict with Hamas.
They said a less inflammatory move, such as a firm non-binding statement, that would threaten tougher action at the next board meeting in March was more likely for now.
"We can't have a resolution," said the senior European diplomat. "If we were to pass a resolution ... it risks pushing them (the Iranians) over the edge ... to 90% enrichment."
Weapons-grade uranium is around 90% purity.
Two diplomats said all that could be done in coming months was to support IAEA chief Rafael Grossi's efforts to strengthen oversight of Iran's nuclear programme. He has been seeking to re-designate his inspectors before the end of the year.
"It's way too early to say whether Iran will become a nuclear state or whether it will stay a threshold state like now," one diplomat said. "But for now it will keep enriching."
