Tehran and West Agree on Parameters of Deal for Iran’s Nuclear Program

Accord envisages strong constraints and controls on Iran for up to 25 years in exchange for lifting of sanctions

LAUSANNE, Switzerland—Iran and six world powers agreed to a path that would block Tehran from developing nuclear weapons, but key points left unresolved in the marathon negotiations and fierce regional and U.S. political opposition suggested major hurdles remain to reaching a final deal.

Officials laid out on Thursday what amounted to goals for a deal by the end of June that would place constraints and controls on Iran’s nuclear work for up to 25 years, with severe limits for the first decade.

But it was still unclear how two of the major sticking points in the final days of negotiations would be resolved. One unanswered question was when exactly sanctions would be eased, and the other was how quickly Iran would be able to scale up its nuclear activities after the first decade.

President Barack Obama hailed it as a “historic understanding” between two estranged nations. “I am convinced that if this framework leads to a final, comprehensive deal, it will make our country, our allies, and our world safer,” he said from the White House. “This has been a long time coming.”

Congressional Republicans quickly attacked the framework, suggesting a drawn-out political fight. Israeli Prime Minister Benjamin Netanyahu said a deal based on the framework would “threaten the survival” of his country.

When the understanding was finally announced two days beyond a March 31 deadline, it contained a surprising amount of detail, given expectations that it would be a more vague political statement.

American officials said the emerging deal, if implemented, would keep Iran at least a year from amassing enough nuclear fuel to develop a nuclear weapon. That is in line with a key Western demand. Iran’s so-called breakout time is currently two to three months.

In exchange, the Islamic Republic will be freed from crippling Western sanctions that have cut its oil exports in half over the past two years.

Iranian Foreign Minister Javad Zarif stressed his country was still committed to developing an industrial-scale nuclear program for peaceful purposes. But he made clear the deal wasn’t guaranteed to lead to diplomatic rapprochement between Tehran and Washington, who have been in conflict for nearly 40 years.

“We have serious differences with the United States,” Mr. Zarif said. “What I hope is that through courageous implementation of this…some of this distrust can be remedied.”

Many of America’s closest Mideast allies, particularly Israel and Saudi Arabia, have warned Washington against concluding a deal with Tehran. Arab countries, in particular, worry the U.S. is seeking to forge a closer relationship with Shiite Iran to confront radical Sunni groups, such as Islamic State and al Qaeda.

The agreement announced in Lausanne is expected to have broad impact on the Middle East. Mr. Obama began the negotiations with Tehran in secret, fueling anger in Arab capitals and charges the White House had been operating behind their back. In recent months—after the talks have gathered pace—the U.S. war against Islamic State militants has at times placed it on the same side as Iran, particularly in Iraq.

The emerging deal with Iran is also sparking fears that it could fuel an arms race in the region. Officials and royals in Saudi Arabia have said in recent weeks that the kingdom will match any of the nuclear technologies Iran maintains as part of the agreement. Saudi officials have also told U.S. administrations that they could seek to cooperate with Pakistan—a nuclear weapons state—to counter Iran.

The Senate is expected to vote April 14 on legislation that would give lawmakers final approval of a deal. The White House has threatened to veto that bill, as well as another that would apply additional sanctions if negotiators don’t reach a deal by the end of June.

The U.S. said all U.N. Security Council sanctions resolutions against Iran would be lifted once Iran carries out all key steps in the agreement, something that would have to be verified by the U.N.’s nuclear watchdog.

Removal of sanctions could provide a big economic boost for Iran’s stagnant economy, Western diplomats have said, allowing a broad range of energy, trade and financial ties to the rest of the world to be re-established.

A wide range of economic and financial sanctions approved by the U.N Security Council would be suspended once Iran implements important elements of the deal. Under the framework, six Security Council resolutions against Iran over its nuclear program would be scrapped.

But a new resolution would be passed which would maintain severe restrictions on sales of material that could be used in Iran’s nuclear program. It would also place unspecified limitations on exports of arms to Iran and on materials that can be used in its ballistic missile program.

According to U.S. Secretary of State John Kerry, European Union and U.S. nuclear-related sanctions on Iran would start to be lifted within four to 12 months of a final deal, but only depending upon how quickly Iran moved to implement its key pledges under the deal.

Under Thursday’s agreement, the EU would suspend its economic, energy and banking sanctions which include an oil embargo on Iran. The U.S. would roll back a range of sanctions that penalize U.S. domestic and foreign companies for establishing economic and financial ties with Iran, including with its central bank.

U.S. sanctions tied to terrorism, human rights and its ballistic missiles program, however, would remain in effect. The U.S. wouldn’t terminate those sanctions, a move requiring congressional oversight, for “much of the duration” of the agreement.

As Iran and the six-power group had long said, many of the key details in the framework still needed to be fleshed out to reach a final nuclear agreement.

U.S. officials provided a number of important details for the constraints that Iran’s nuclear program would face.

Iran would see the number of installed centrifuges—machines used to enrich uranium—cut from around 19,000 at present to 6,104, of which only 5,060 would be able to operate for the first decade. All of those machines would be older, first-generation centrifuges.

Low-enriched uranium can be used as fuel for nuclear energy while uranium enriched to higher levels can be used to fuel nuclear weapons. Iran has agreed not to enrich uranium to a level above 3.67% for 15 years, significantly lower than the 90% purity needed for weapons grade material. That limitation was stronger than expected.

Enrichment of uranium would only take place at Iran’s Natanz nuclear facility. There would be some centrifuges at the heavily fortified, underground nuclear facility of Fordow. Iran would be unable to enrich uranium there and would stock no fissile material at the site.

Iran has also agreed to cap its stockpile of low-enriched uranium to 300 kilograms from the current roughly 10,000 kilograms. It would be limited at that level for 15 years, although it is unclear whether Tehran would ship the material out of the country.

Mr. Obama said a diplomatic deal is the only viable solution to keeping Iran from obtaining a nuclear weapon, absent military action. But he hinted at the diplomacy’s fragility by noting the success of a final accord is far from guaranteed.

“Our work is not yet done. The deal has not been signed,” Mr. Obama added. “And success is not guaranteed.”

The U.S. president said there are several potential obstacles to reaching a full agreement by the June 30 deadline, including Congress, U.S. allies in the Middle East and the Iranian regime.

Mr. Obama said he invited the leaders of the countries that make up the Gulf Cooperation Council—Saudi Arabia, the United Arab Emirates, Kuwait, Oman, Qatar and Bahrain—to meet this spring at Camp David, the sprawling presidential retreat in Maryland. He also vowed to make his case to Congress and the American public.

He said he planned to speak with congressional leaders and had spoken with Mr. Netanyahu on Thursday.

“If Congress kills this deal—not based on expert analysis, and without offering any reasonable alternative—then it’s the United States that will be blamed for the failure of diplomacy. International unity will collapse, and the path to conflict will widen,” Mr. Obama said.

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