Day one of a six-month period of reduced Iranian nuclear activity and a slight easing of economic sanctions begins Monday. The interim accord may be a high-water mark for nuclear diplomacy, but soon negotiators must begin to fashion a comprehensive nuclear accord in the face of widespread skepticism.
Each side is sniping at the other's interpretation of the relatively modest steps agreed to thus far.
Iran's president Hassan Rouhani has been sounding nearly as provocative as his predecessor Mahmoud Ahmadinejad lately, boasting that the deal reached in November represents a total capitulation by the West. Israeli and American conservatives are sounding alarms about such talk, even though diplomats say it's intended to placate Iranian hardliners.
Ali Ansari, professor of Iranian history at St Andrew's College in Scotland, says Rouhani is indeed under increasing pressure and not only from the hardliners.
"There is some criticism, interestingly enough, from reformists on the other side of the political spectrum, who are arguing that many of the promises that Rouhani made about political reform in order to win election last June have really remained unfulfilled, and that he's not addressing them at all," Ansari says. "So Rouhani finds himself really under attack from two quite distinct political groups, and both of them expose some of his fragility."
Until now, there have been two tracks of discussions one between Iran and the six world powers known as the "P5+1" and one between Iran and the International Atomic Energy Agency (IAEA). Now those tracks are beginning to converge. Starting Monday, IAEA inspectors will make daily visits to verify Iran's pledges to stop its highest level enrichment of uranium and reduce its existing stockpile.
Iran analyst Ali Vaez at the International Crisis Group says the sides are far apart on all the remaining major issues although he says if the political will is there, technically most of the outstanding questions can be answered in the upcoming talks.
"I think all the remaining contentious issues have technical solutions," Vaez says. "The real issue is finding a way that would allow each side to sell the deal back home to those who oppose it from a political perspective, rather than a technical perspective."
Take one important issue: Iran's heavy-water reactor being built at Arak. Experts say there are ways to ensure that Iran doesn't create plutonium, useful for a nuclear weapon, from the reactor's spent fuel. But they would entail concessions that deeply disturb hardliners on both sides. Vaez says more bilateral talks between Washington and Tehran may be needed to keep things on course.
Ansari says negotiators must be allowed to focus on the task at hand, without either the panicky cries of critics or the unrealistic optimism of those who want to imagine a completely new relationship between Iran and the West.
"And to my mind, I have to say, I think the optimism of the early days and the great euphoria, I think has been very unhelpful," Ansari says. "We would've been much better to play down the prospect of success and see a success, rather than raise expectation and find that we are all bitterly disappointed because the disappointment will be quite disastrous, if it happens."
There are at least two moves afoot that critics say will scuttle the talks. A bill with bipartisan support in the U.S. Congress would add new sanctions soon after this six-month interim period expires. In Tehran, lawmakers say if any new sanctions are imposed, they will require the country to enrich uranium to 60 percent dangerously close to weapons-grade fuel.