There is much work to be done and much that can still go awry, but April 2, 2015 will go down in history as the day when the Islamic Republic of Iran and the United States finally got to yes.

After 36 years of mutual demonization, proxy wars and occasional direct conflict, the two old adversaries, joined by negotiators from other major world powers, agreed in Lausanne, Switzerland on a framework for a long-term deal curbing Iran’s nuclear program and potentially doing much more.

The framework, which is to be finalized by June 30, would set specific limits on Iran’s nuclear activities for periods ranging from a decade to indefinitely. It was the product of negotiations that go back more than 10 years but that really only became serious 18 months ago. That’s when a new team of Iranians joined the talks following the election of President Hassan Rouhani, whose cabinet contains more U.S.-educated PhDs than that of President Barack Hussein Obama.

This team, led by Foreign Minister Javad Zarif, whose PhD comes from the school of international affairs founded by former Secretary of State Madeleine Albright’s father at the University of Denver, set out to preserve as much of Iran’s nuclear infrastructure as possible while providing guarantees that it could not be used to make weapons.

On Thursday, an exhausted but jubilant Zarif proclaimed victory, saying negotiators had achieved a win-win deal that had “stopped a cycle that was not in the interest of anyone.”

Obama, too, exuded satisfaction as he read a statement to reporters in the White House Rose Garden. While Zarif focused on the sanctions relief that long-suffering Iranians would receive, Obama laid out the ways in which the agreement would verifiably block Iran’s pathway to nuclear weapons for at least 15 years.

Iran, Obama said, would dismantle and replace the core of a heavy water reactor under construction at Arak so that it produces less plutonium – a potential bomb fuel — and will ship out spent fuel for the life of the reactor. Iran will not build another such reactor or reprocess the plutonium, he said.

On uranium enrichment, where Iran has made major advances, Tehran will cut installed centrifuges by two-thirds, stop enriching uranium at an underground facility, not use advanced centrifuges for a decade, not enrich beyond 3.67 percent and limit its stockpile of this low-enriched uranium to 300 kilograms – not enough for a single weapon – for 15 years. Taken together, these measures would insure that Iran could not amass enough material for a bomb in a year – the so-called breakout period, which at present is only two or three months.

Finally, Obama said, Iran has accepted unprecedented, stringent verification measures that will make it extremely difficult for it to pursue a covert path to nuclear weapons. “If Iran cheats, the world will know it,” the president said. He also pointed out that as a member of the Nuclear Non-Proliferation Treaty, “Iran will never be permitted to develop a nuclear weapon.”

In return, Iran would get phased relief of U.S., European Union and U.N. sanctions that have crippled its economy particularly in the last three years.

Thursday’s breakthrough – which coincided with the end of the two-week Nowruz or New Year’s holiday in Iran — brought cautious optimism from ordinary Iranians who have seen their hopes for sanctions relief and better relations with the U.S. rise and fall repeatedly over the years. Many however, watched television where for the first time, they got to see an American president speak live; some people took selfies of the screen image of Obama and themselves to mark the moment and post on social media.

Zarif returned home Friday to a hero’s welcome.

Reaction elsewhere varied. While many U.S. allies and American Democrats heralded the breakthrough, Israeli Prime Minister Benjamin Netanyahu continued a bitterly negative refrain. He told Obama – who called the Israeli leader after the announcement – that the deal as outlined “would threaten the survival of Israel.”

Obama told reporters, “It’s no secret that the Israeli Prime Minister and I don’t agree about whether the United States should move forward with a peaceful resolution to the Iranian issue,” but insisted that the diplomatic route chosen by the U.S. and the other permanent members of the U.N. Security Council plus Germany is “the most effective way to ensure Iran doesn’t get a nuclear weapon.”

Before making the news public, Obama also called Saudi King Salman – another Iranian adversary – and invited him and other leaders of the Gulf Cooperation Council to Camp David this spring to discuss ways to shore up their security against what they fear will be an emboldened Iran that already exerts influence in Lebanon, Syria, Iraq and Yemen.

Later, a senior administration official, speaking on condition of anonymity, acknowledged that the U.S. government “will have to sell this deal” to Israel, Sunni Muslim Arabs and a skeptical Republican-led Congress.

Some GOP leaders blasted the framework in Netanyahu-like terms expressing concern that Iran would use new revenues acquired from eased sanctions to foment more instability and aggression against U.S. allies in the Middle East.

However, Bob Corker, chairman of the Senate Foreign Relations Committee – which is due to mark up new and potentially deal-killing legislation when it returns from Easter recess April 14 – gave a more measured response.

“It is important that we wait to see the specific details of today’s announcement, and as the P5-plus-one works toward any final deal, we must remain clear-eyed regarding Iran’s continued resistance to concessions, long history of covert nuclear weapons-related activities, support of terrorism, and its current role in destabilizing the region,” the Tennessee Republican said in a statement. “If a final agreement is reached, the American people, through their elected representatives, must have the opportunity to weigh in to ensure the deal truly can eliminate the threat of Iran’s nuclear program and hold the regime accountable.”

For others, the announcement brought a sense of closure and the prospect for real U.S.-Iran cooperation in calming a Middle East in meltdown.

Former national security adviser Zbigniew Brzezinski, who served three decades ago when U.S.-Iran relations collapsed in the chaos of the revolution and the seizure of U.S. diplomats as hostages, told VOA that the Iran announcement was a “victory for President Obama and geopolitical stability.”

The views and opinions expressed are those of the author and do not necessarily reflect the position of Voice of America.

Barbara Slavin is a senior fellow at the Atlantic Council’s South Asia Center and a correspondent for Al-Monitor.com, a website specializing in the Middle East. She is the author of a 2007 book, Bitter Friends, Bosom Enemies: Iran, the US and the Twisted Path to Confrontation, and is a regular commentator on U.S. foreign policy and Iran on NPR, PBS, C-SPAN and the Voice of America

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