Iran and world powers have reached a diplomatic breakthrough that could lead to a final settlement of the 12-year-long confrontation over the Islamic Republic's nuclear program. That's the clear message that emerged from marathon talks in Lausanne, which ran two days past a self-imposed Tuesday deadline well into Thursday evening local time.
"Today we have taken a decisive step," EU foreign policy chief Federica Mogherini told reporters after eight days of talks. "We have reached solutions on key parameters of a joint comprehensive plan of action. The political determination, the goodwill, and the hard work of all parties made it possible."
Iran, the five permanent UN Security Council members and Germany would now move to draft the text of a final settlement by June 30th, according to Mogherini. Iranian Foreign Minister Javad Zarif subsequently read the same statement in Farsi.
A diplomatic breakthrough in Switzerland wasn't a foregone conclusion. During the eight days of talks, stubborn differences had emerged over how long limitations on Iranian nuclear research should last and the pace at which sanctions should be lifted.
"In essence, it's about trying with one single agreement to overcome not just differences over a nuclear issue, but fundamentally beyond that overcome almost four decades of suspicion between Iran on the one hand and particularly the United States on the other hand," Alex Vatanka, an Iran analyst at the Middle East Institute, told DW.
Some specifics were made public. Under the tentative agreement, Iran is permitted to produce low-enriched uranium only at its facility in Natanz, but it's barred from using its more advanced centrifuges for the next decade. Tehran will reduce its 19,000 centrifuges by two-thirds and cut its low-enriched uranium stockpile from 10,000 to 300 kilograms.
In addition, the Fordow facility will be converted from an enrichment to a research center, and fissile material will not be stored there. The international community will assist Iran in dismantling the reactor core at the site in Arak, preventing the production of weapons-grade plutonium, and ship the spent fuel out of the country.
In a statement made at the White House, US President Barack Obama called the agreement a "good deal," saying that the conditions "would cut off every pathway" Iran can take to produce a nuclear weapon - whether through plutonium or uranium. The president said sanctions would be lifted in a staged process after verification by the most comprehensive international inspections of a nuclear program in history.
"Today the United States with its allies and partners has reached a historic understanding with Iran, which, if fully implemented, will prevent it from producing a nuclear weapon," the president said.
Nuclear threshold state
Under these conditions, Iran would need about a year to produce enough fissile material for a nuclear bomb, providing the international community with a buffer to take action if the terms of the agreement are violated. These limitations would last a decade. Iran would essentially be accepted as a de facto nuclear threshold state.
"Even if some people will argue they could do it somewhat faster than a year, it will take many months to make enough bomb material at those declared facilities, and those facilities wouldn't continue to exist for that period of time - somebody would destroy them," Matthew Bunn, co-principal investigator at Harvard's Project on Managing the Atom, told DW.
In exchange, the world powers - particularly the United States and the European Union - would gradually lift the economic sanctions as Iran meets its obligations under the agreement. After verification by the IAEA, Washington and Brussels would lift economic and financial sanctions related to nuclear research. But the most crippling sanctions target Iran's oil exports and lock the country out of the international financial system. It's still unclear when those would be lifted.
"The lifting of sanctions will create a flow of benefits to powerful people in the regime in Iran that they won't want cut off," Bunn said. "There will be more people saying, 'Do we really want to rip this up to go for the bomb now?'"
But if such a deal becomes reality, implementation could prove difficult. In essence, world powers are offering sanctions relief in exchange for the promise of future cooperation from Iran. As a consequence, an extensive and intrusive regime of inspections would be necessary to verify that Tehran is indeed meeting its obligations, according to Christopher Bidwell, with the Federation of American Scientists.
"The starting point is something that may be difficult for Iran to do and that's to give a full, complete and accurate declaration of what they've been doing so far in the nuclear field," Bidwell told DW.
"You need end-to-end knowledge of Iran's nuclear program to know where your starting so that you know - as you do your verification investigation - that the numbers are adding up," he said. "Otherwise, you're shooting in the blind."
Even if Iran does provide a declaration of its nuclear activities, there's still the risk that it could continue some enrichment and research activities in secret. But according to Bunn, an agreement offers a better chance of uncovering covert operations than no agreement.
"The most important aspect on covert has been having good intelligence, but this will help with the expanded inspections," he said.
Though Tehran and the world powers have agreed to a framework, the painstaking details of a final deal still have to be hammered out. Plenty could go wrong before the June 30th deadline. If conservatives in the US Congress secure a veto-proof majority and make good on their threat to impose additional sanctions against Iran, the negotiations and any hope of a final deal would be dead.
Israeli Prime Minister Benjamin Netanyahu has also been a staunch opponent of any nuclear settlement between Iran and the United States that allows uranium enrichment. Seeking to mobilize opposition in America, he delivered a speech to Congress slamming a nuclear deal earlier last month. President Obama acknowledged on Thursday his differences with Netanyahu, but said that the US was in close contact with Israel and remained committed to its security.
There's also the threat from conservatives in Tehran. Ayatollah Khamenei, Iran's supreme leader, has the final say and could reject the terms of an agreement if he views it as violating the country's sovereignty. But Vatanka with the Middle East Institute believes that both sides are determined to reach final settlement because there are no viable alternatives.
"In the absence of war and those who advocate for regime change in Iran, which I don't think is realistic at all if you look at America's options in the Middle East, then both sides here have something they can take home," Vatanka said. "[Both can] say it's not the best of deals, but the alternative would have been worse."