The U.S., Iran and five world powers on Thursday reached a preliminary deal designed to contain Iran’s nuclear program, one that would restrict Iran’s ability to enrich uranium and subject it to international inspections, but which also would gradually remove harsh economic sanctions from the Islamic Republic.

The agreement, if it holds, could prove to be President Barack Obama’s biggest foreign policy achievement, a success stemming from his conviction that it’s worth engaging even longtime adversaries such as Tehran. But while the framework won praise for its surprising level of detail, it failed to quell sharp skepticism from many Republicans as well as Israeli Prime Minister Benjamin Netanyahu.


“It is a good deal,” Obama declared Thursday, calling it “a historic understanding with Iran which, if implemented, will prevent it from obtaining a nuclear weapon.

“I am convinced that if this framework leads to a final deal, it will make our country and the world safer,” Obama said in a appearance at the White House Rose Garden. The deal, unveiled in Lausanne, Switzerland, would “cut off every pathway that Iran could take to develop a nuclear weapon.”

Obama struck a confident tone, directly engaging potential critics including Netanyahu and Republicans in Congress. Pointing to the possibility for military conflict should the talks ultimately fail, Obama said, “I welcome a robust debate.”

That debate started immediately.

Netanyahu, speaking several hours after the deal was announced, said “The concessions offered to Iran in Lausanne would ensure a bad deal that would endanger Israel, the Middle East and the peace of the world. Now is the time for the international community to insist on a better deal.”

House Speaker John Boehner, who has been on a trip to the Middle East, questioned elements of the deal related to sanctions relief. The Republican insisted: “It would be naive to suggest the Iranian regime will not continue to use its nuclear program, and any economic relief, to further destabilize the region.”

Obama said he saw three options: The first, the U.S.’ current path of a negotiated agreement with Iran. Second, bombing Iran’s nuclear facilities, a move he warned would set its program back only “by a few years.” The third option, Obama said, was to “pull out of negotiations … and hope for the best.”

“Iran is not going to dismantle its program because we demand it do so,” he said. “That’s not how the world works.”

Obama said he had already called Saudi Arabia’s King Salman before his Rose Garden speech. But Obama did not call Netanyahu until well after his remarks — during a flight to Louisville, Kentucky, aboard Air Force One. According to the White House, the president told Netanyahu the deal “in no way diminishes our concerns with respect to Iran’s sponsorship of terrorism and threats towards Israel.” Obama also directed his national security team to “increase consultations” with the Israeli government. The Israeli readout of the call said that Netanyahu stressed that the deal would threaten Israel’s existence.

The agreement itself was announced in Lausanne by European Union foreign policy chief Federica Mogherini and Iranian Foreign Minister Javad Zarif.

What was laid out Thursday was essentially a broad a framework; a more comprehensive, technical deal is expected by June 30. Still, the result caught many close observers by surprise after reports from the shores of Lake Geneva suggested talks were heading toward a vague press statement of principles — or outright impasse.

“I was expecting either no agreement today or a much thinner one,” said Richard N. Haass, president of the Council on Foreign Relations. “It is more substantive and more comprehensive than many us thought would be the case.”

Haass specifically praised the extent of monitoring of the nuclear supply chain and concessions on the number of centrifuges. But given the amount of work to be done before June 30, “no one should be popping champagne today,” Haass cautioned. “For all we know, there will be backtracking.”

Crucial elements of the deal include:

— Iran will dismantle two-thirds of its 19,000 installed centrifuges. Those devices, which spin uranium into material that can be used for a nuclear weapon, will be stored under International Atomic Energy Agency oversight. Tehran will be left with 6,104 centrifuges, lower than some reported offers by the U.S., and 5,060 of those can be used to enrich uranium.

— Iran can keep open an underground nuclear facility at Fordow, a controversial site because it was built in secret and only revealed by the U.S. in 2009. Iran will not be required to close the facility but could use it only for research that does not include the enrichment of uranium.

— Rigorous transparency and inspection measures to ensure that Iran doesn’t cheat on any deal. They include granting the IAEA intrusive access to Iran’s nuclear facilities and supply chain, including to its domestic uranium mines and mills. The inspections would continue even after many elements of the deal have expired in 2025, including surveillance of Iran’s centrifuge rotors until 2035. Iran has also agreed to some indefinite transparency measures.

— In return for the limits on Iran’s program, the U.S. and EU will suspend sanctions after the IAEA has verified Iran’s compliance with the deal; those sanctions can automatically “snap back” if Iran violates the agreement at any time. (Obama can temporarily suspend sanctions passed by Congress, although only Congress can permanently repeal them.) The United Nations will also lift its sanctions on Iran after it meets the deal’s requirements.

Speaking in Lausanne, Secretary of State John Kerry called the framework “a critical milestone” and “a solid foundation for the good deal we are seeking.”

The exact timing of sanctions relief, he noted, “remains one of those issues that is going to be negotiated over the course of the next three months.” In general, he said, “Iran has the responsibility to get the breakout time to one year” — meaning it has to prove to the satisfaction of international inspectors that it would take at least a year to develop a nuclear weapon, so there would be plenty of advance warning if Iran tried to do that. Once IAEA inspectors certify that Iran has met those conditions, Kerry said, sanctions will begin to be reduced.

The deal, key points of which were sent out to reporters by the White House, was unclear on some crucial questions that critics are sure to pounce on:

— Although the agreement specifies that Iran will dramatically “reduce” its current stockpile of low-enriched uranium by 97 percent, from 10,000 kilograms to 300 kilograms, details of the agreement provided by the Obama administration do not say how that will happen. U.S. officials are expected to require Iran to ship that material — which is more than halfway to the potency needed for a bomb — out of the country. But Iran has proposed to retain the material and simply dilute it to a form unsuitable for a nuclear weapon, although that dilution is reversible.

Kerry, however, said in Lausanne that negotiators have a resolution on what to do with Iran’s uranium: “It has to be either diluted or sold on the international market, one of the two. … That is agreed upon at this point in time,” he said.

— Iran has refused to answer a list of IAEA questions about its suspected past research into nuclear weapons technology, like explosives that can detonate highly enriched uranium. The agreement does not specify how or when that will happen, saying only that “Iran will implement an agreed set of measures to address the IAEA’s concerns” on the military research question. Mogherini said only that the nuclear agency “will have enhanced access through agreed procedures, including to clarify past and present issues.”

Oil-rich Iran has long insisted its nuclear program is for scientific, medical and other purposes, not for making weapons. On Thursday, Zarif said Iran has agreed to take steps to assure the world “that our program is exclusively peaceful, that our program always has been and always will be exclusively peaceful.” But, he added, Iran will not close any of its nuclear facilities — a condition it said would have been unacceptable. “We have done significant work. We have made achievements. We have made progress,” Zarif said.

Obama stressed in particular the inspection and verification aspects of the agreement.

“If Iran cheats, the world will know it. If we see anything suspicious, we will inspect it,” Obama said. He said Iran will face “more inspections than any other country in the world.” And he said the relief from sanctions will be “phased” as long as Iran proves it is complying with the terms of an agreement.

“If there is backsliding on the part of the Iranians,” he said, “there will be no deal.”

Kerry contended that the deal has no sunset date. In reality, most of its provisions — how many centrifuges Iran can run, for instance — will expire after a decade. But Iran has agreed to a special arrangement with the IAEA known as the Additional Protocol, which grants the international agency’s inspectors enhanced information about and access to the country’s nuclear activities and infrastructure. The Additional Protocol has no time limit.

The deal’s announcement came after a final round of negotiations in Lausanne, following a grueling marathon session that kept officials talking until 6 a.m. Thursday — and two days after a self-imposed deadline to reach a political agreement. Aside from the U.S. and Iran, countries participating include Germany, France, Britain, Russia and China.

Earlier this week, the Obama administration started signaling its impatience with the Iranians, with White House press secretary Josh Earnest warning Wednesday that the negotiations would not be “open-ended.” The Iranians also dug in, repeatedly pointing to sanctions relief as a major concern.

The agreement could end up at the mercy of U.S. domestic politics, and it was fast fodder for Republicans hoping to succeed Obama in the White House.

“This attempt to spin diplomatic failure as a success is just the latest example of this administration’s farcical approach to Iran,” Florida Sen. Marco Rubio, who is expected to announce his bid for the Republican nomination this month, said in a statement.

Congressional leaders also insist they want a say in any deal. GOP Sen. Bob Corker, chairman of the Senate Foreign Relations Committee, said it was “important that we wait to see the specific details,” but he did not back away from his pledge to pass bipartisan legislation giving Congress the right to block an accord.

A poll out Monday showed that 49 percent of Americans support the talks, while 40 percent disapprove. About two-thirds of respondents to the Pew Research Center poll do not think Iran is serious about “addressing nuclear concerns.”

Many Iranians, who have watched their economy wobble underneath international sanctions, were thrilled over the deal. Photos from Iranian and Western outlets showed young Iranian men and women cheering in the roads and flashing victory signs from their cars Thursday evening.

But there were also signs of discontent among Iranian hardliners. According to Iran’s semi-official Fars News Agency, Hossein Shariatmadari, editor of the conservative Kayhan newspaper, declared of the deal: “We gave them a saddled horse in return for some broken reins.”

Nahal Toosi contributed to this report.