WASHINGTON - Negotiators at the nuclear talks in Switzerland last week emerged with a surprisingly detailed outline of the agreement they now must work to finalise by the end of June.
But one problem is that there are two versions.
The only joint document issued publicly was a statement from Iran's Foreign Minister Mohammad Javad Zarif and the European Union's foreign policy chief Federica Mogherini that was all of seven paragraphs.
The statement listed about a dozen "parameters" that are to guide the next three months of talks, including the commitment that Iran's Natanz installation will be the only location at which uranium is enriched during the life of the agreement.
But the United States and Iran have also made public more detailed accounts of their agreements in Lausanne, and those accounts underscore their expectations for what the final accord should say.
A careful review shows that there is considerable overlap between the two accounts but also some noteworthy differences - which have raised the question of whether the two sides are entirely on the same page, especially on the question of how quickly sanctions are to be removed.
The American and Iranian statements do not clarify some critical issues, such as what sort of research Iran will be allowed to undertake on advanced centrifuges during the first 10 years of the accord.
"This is just a work in progress, and those differences in fact sheets indicate the challenges ahead," said Mr Olli Heinonen, former deputy director-general of the International Atomic Energy Agency.
US officials insist there is no dispute on what was agreed behind closed doors. But to avoid time-consuming deliberations on what would be said publicly, the two sides decided that each would issue its own statement.
"We talked to them and told them that we would have to say some things," said a senior US administration official, who could not be identified. "We didn't show them the paper. We didn't show them the whole list."
The official acknowledged it was "understood that we had different narratives, but we would not contradict each other".
But no sooner had the negotiations ended last Thursday than Mr Zarif sent out a tweet that dismissed the US parameters as "spin".
In an appearance on Iranian state television last Saturday, he kept up that refrain, saying Iran had formally complained to Secretary of State John Kerry that the measures listed in the US statement were "in contradiction" to what had actually been accepted in Lausanne.
But Mr Zarif did not challenge any nuclear provisions in the US document. Instead, he complained that the paper had been drawn up under Israeli and US congressional pressure, and he restated Iran's insistence on fast sanctions relief.
Mr Zarif, who was welcomed back to Teheran by cheering crowds last Friday, must now convince a domestic audience that the talks are heading towards a final deal that is in Iran's interest.
Mr David Albright, president of the Institute for Science and International Security who has closely monitored the talks, said Iranian President Hassan Rouhani and Mr Zarif may be engaged in their own spin to camouflage the significance of the concessions they made.
"Iran conceded a considerable amount in this deal, and Zarif and Rouhani may want to break the news back home slowly," Mr Albright said.
Assuming that was the Iranians' motivation, Mr Albright noted a potential downside to the tactics.
"When negotiations resume, Iran may believe it created additional room to backtrack on its commitments, assuming the US is right about what was agreed in the room," he said.
A second Obama administration official said: "We fully expected them to emphasise things that are helpful in terms of selling this at home... We believe that everything in our document will not need to be renegotiated."
But with three months of hard bargaining ahead, some experts worry that the lack of an agreed- upon, detailed public framework can only complicate the negotiations - and may even invite the Iranians to try to re-litigate the terms of the Lausanne deal.
"I think it is a troubling development," said senior fellow Ray Takeyh at the Council on Foreign Relations, who has been critical of the Obama administration's handling of the talks.
"They will exploit all ambiguities with creative interpretations." Yesterday, Iran's military chief hailed the success of his country's negotiators in the talks. General Hassan Firouzabadi is a close ally of Iran's Supreme Leader,
Ayatollah Ali Khamenei, who has yet to comment on the agreement.
This article was first published on April 6, 2015.
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