The U.S. and Iran are exploring a nuclear deal that would keep Tehran from amassing enough material to make a bomb for at least a decade, but could then allow it to gradually build up its capabilities again.
Such a deal would represent a significant compromise by the U.S., which had sought to restrain Tehran’s nuclear activities for as long as 20 years. Tehran has insisted on no more than a 10-year freeze.
The possible compromise on the table appears closer to Tehran’s timeline. While it would add some years in which the Iranian nuclear program continues to be closely monitored and constrained, Iran would be able to increase its capacity to enrich uranium, and thus get closer to bomb-making capability again.
Critics in Congress and in Israel quickly attacked the prospect of a 10-year time frame as inadequate.
After four days of talks in Geneva, a senior U.S. official on Monday said there had been welcome progress toward a deal, while giving no specifics about its timeline.
The U.S. has been pushing for a freeze that would establish a period of time during which Iran would remain at least 12 months away from being able to fuel an atomic bomb—a so-called breakout period. Asked if Iran must accept that breakout period through the lifetime of an accord, the person signaled that may not be necessary.
“We have always said that we would have a one-year breakout time for a double-digit number of years and that remains the case,” the official said.
That suggests a period of as little as 10 years. When pressed, the official declined to elaborate.
Such a compromise could allow Iran to portray the major restrictions on its nuclear program at home as lasting only 10 years—an upper limit Iranian officials have mentioned before. Iran says its nuclear program is a purely civilian, peaceful one.
It also could break the impasse over how many centrifuges—machines for enriching uranium—Tehran would be allowed under a deal. If Iran can expand its activities, it could start with fewer centrifuges and then be allowed to operate more over time.
The U.S. and its global partners could argue that Tehran’s activities will remain under significant international oversight and with some constraints for much longer.
U.S. lawmakers have said they’re going to closely scrutinize any agreement with Tehran and try to force a vote in Congress on it. A deal that allows Tehran to maintain a sizable capacity to enrich uranium, and to eventually be freed to pursue a broader nuclear program, is expected to face fierce opposition.
The Obama administration maintains that it doesn’t need congressional approval for the deal because it isn’t a treaty, although Congress would have to vote to lift some of the sanctions it has imposed on Iran over the years.
Sen. Bob Corker (R., Tenn.) said in an interview that a 10-year time frame wasn’t long enough to truly curb Tehran’s nuclear ambitions.
“If you’re going to do all of this and then just end up with a 10-year agreement, you just really haven’t accomplished near what people had hoped,” said Mr. Corker, who chairs the Senate Foreign Relations Committee.
Such a time frame would be “very concerning,” he added. “About the time they’re beginning to do what they should be doing, they’d be out from under the regime.”
The Israeli government has been a leading critic of the talks, which Prime Minister Benjamin Netanyahu on Sunday warned were destined to end in a “dangerous” deal.
On Monday, Israeli Intelligence Minister Yuval Steinitz said Israel considers the negotiations “totally unsatisfactory” because it would allow Iran to be “extremely close” to a “dangerous breakout program.”
Referring to the latest suggested compromise, he said, “for a 10-year delay [in Iran’s nuclear program] you are sacrificing the future of Israel and the U.S., and the future of the world.”
Mr. Netanyahu will travel to Washington next week to make his case against the diplomacy. He is due to deliver a speech to Congress on March 3, at the same time U.S. and Iranian diplomats will be back in Europe seeking to advance work on a deal. The two sides are aiming to complete a framework deal by late March and have a full, detailed agreement by a June 30 deadline.
U.S. lawmakers have threatened to impose fresh sanctions on Iran if the March deadline is missed—a step that could scuttle the diplomacy.
The talks in Geneva were attended by U.S. Secretary of State John Kerry and, for the first time, by U.S. Energy Secretary Ernest Moniz. They met Sunday evening and Monday with Iranian Foreign Minister Javad Zarif and the head of Iran’s atomic agency Ali Akbar Salehi.
Both sides said the expansion of the negotiations to other top-level officials aimed at cutting through the remaining complex issues.
“These were very serious, useful and constructive discussions. We have made some progress though we still have a long way to go,” the senior U.S. official said.
Mr. Zarif was quoted by Iranian state media as saying: “We have made progress on some topics to some extent, but there is still a long way to go before reaching a final deal.”
Russia’s deputy foreign minister and chief Iran negotiator, Sergei Ryabkov, reflected a palpable sense of optimism around the decadelong talks. “Confidence is growing a deal can be reached,” he said.
Iran negotiates over the future of its nuclear program with the U.S., France, the U.K., Germany, Russia and China.
Western officials said a phased structure could apply in other areas as well, such as when international sanctions on Iran will be lifted, or when Iran could resume nuclear research. Still, Western diplomats insisted that real differences remained.
The concerns about Iran’s research work are a threat to any agreement on the enrichment issue. If Tehran is able to develop far more powerful centrifuges, Iran would be able to produce enough nuclear material for a bomb in less than a year.
“The U.S. has gone a long way” toward accepting Iran’s position, said David Albright, who heads the Institute for Science and International Security, a think tank that has advised Congress. “If they don’t address these issues in some way, then this deal isn’t doable.”