BRUSSELS — With Iran announcing this week that it now has the technical ability to produce a nuclear warhead, though denying that it plans to, negotiators from the United States and Iran arrived on Thursday in Vienna for one more — and perhaps the last — effort to restore the 2015 nuclear deal that limited Tehran’s nuclear program.
Expectations for the talks, chaired by the European Union, were low. But the negotiations may also lead to a more serious round if the two sides are willing to move on what they have both described as their red lines and make some politically fraught concessions.
The lead negotiator for the United States, Rob Malley, and his Iranian counterpart, Ali Bagheri Kani, traveled to Vienna for the talks after the European Union tabled a draft that is slightly amended from a text largely agreed upon in March. That prompted some hope that Washington and Tehran would in the end agree to revive the 2015 deal, known as the Joint Comprehensive Plan of Action, which former President Donald J. Trump abandoned in 2018, calling it “the worst deal in history.”
Mr. Trump deliberately complicated any chance of revival, not only reimposing severe economic sanctions on Tehran that were lifted in the deal but also imposing hundreds more.
Before the meeting, Mr. Malley suggested that he did not expect major progress. “Our expectations are in check, but the United States welcomes E.U. efforts and is prepared for a good-faith attempt to reach a deal,” he wrote on Twitter. “It will shortly be clear if Iran is prepared for the same.” Iran negotiators still refuse to meet directly with Americans.
Mr. Bagheri Kani said that the burden was on Washington. “The onus is on those who breached the deal & have failed to distance from ominous legacy,” he wrote in his own Twitter message. A spokesman for the Iranian Foreign Ministry, Nasser Kanani, described the talks as “a discussion and exchange of views.”
Speaking at the United Nations, Iran’s ambassador to the global body, Majid Takht-Ravanchi, blamed Washington for failing to guarantee that Iran would receive the pact’s economic benefits. “Achieving this objective has been delayed because the United States is yet to decide to give assurance that Iran will enjoy the promised economic benefits in the agreement,” he said.
The delay has meant that Iran has pressed ahead with its nuclear program so far that it will be difficult to monitor any revived agreement, even if one is reached, suggested the director-general of the International Atomic Energy Agency, Rafael M. Grossi.
“They have a very ambitious nuclear program that needs to be verified in the appropriate way,” Mr. Grossi said on Tuesday. “The program is moving ahead very, very fast and not only ahead, but sideways as well, because it’s growing in ambition and in capacity.”
Iran has denied the agency access to cameras and other monitoring equipment intended to track the progress of its nuclear program, making it very difficult to know precisely how much uranium has been enriched to high levels. “When it comes to nuclear, good words are not enough,” Mr. Grossi said, adding that Iran must grant inspectors access “commensurate to the size” of its uranium enrichment program if the agency is to credibly assure that it is peaceful.
Given the steady advance in Iran’s technical knowledge and stockpile of highly enriched uranium, the country is now considered by many to be a “threshold state,” capable of making a bomb if it wishes, though Tehran denies any intention of ever doing so. That provides Iran with significant clout and could encourage other countries to pursue nuclear weapons, effectively shredding the 52-year-old Nuclear Nonproliferation Treaty.
In July, Kamal Kharrazi, a senior adviser to Ayatollah Ali Khamenei, the supreme leader of Iran, said that the country now had the technical capability to produce an atomic bomb. His comments were repeated on Monday by Mohammad Eslami, head of the Iranian Atomic Energy Organization, according to the semiofficial news agency Fars.
Three weeks ago, Richard Moore, the head of Britain’s foreign intelligence service, MI6, said that he doubted Iran would accept the renewal of the nuclear deal. “I’m skeptical that the supreme leader will go for the deal,” he said, referring to Ayatollah Khamenei. He added that while an agreement was on the table, and despite his belief that China and Russia would not block a deal, “I don’t think the Iranians want it.”
Still, neither Tehran nor Washington are considered likely to declare the negotiations over, because that would present complicated choices about what to do next, given the repeated vows by the United States and Israel that they will do whatever is necessary to prevent Iran from making a nuclear weapon. In mid-July, President Biden and Israel’s prime minister, Yair Lapid, signed a joint declaration saying that the United States would use “all elements of national power” to deny Iran the ability to arm itself with nuclear weapons.
The Biden administration has recently imposed further sanctions on Iran, targeting companies used by the country’s Persian Gulf Petrochemical Industry Commercial Company. Iran then announced that it was activating hundreds of new and advanced centrifuges that had previously been installed at an underground nuclear site in Natanz.
But neither country wants a war.
Nonetheless, Josep Borrell Fontelles, the E.U. foreign policy chief, made what seemed like a final plea in an opinion piece in The Financial Times on July 26, suggesting that the latest draft may be the last.
“After 15 months of intense, constructive negotiations in Vienna and countless interactions with the J.C.P.O.A. participants and the U.S., I have concluded that the space for additional significant compromises has been exhausted,” Mr. Borrell wrote.
“I have now put on the table a text that addresses, in precise detail, the sanctions lifting as well as the nuclear steps needed to restore” the agreement, he added.
“This text represents the best possible deal” that he considered feasible, he noted. “I see no other comprehensive or effective alternative within reach.”