The Economist explains nuclear talks with Iran

FEW issues have vexed diplomats more in recent years than Iran’s controversial nuclear programme. But as negotiators from the Islamic Republic and the P5+1 group (comprising the permanent members of the UN Security Council along with Germany) resume their talks in Vienna on May 13th, the mood is relatively upbeat. A breakthrough deal reached last November provided a breather that has built mutual confidence, with Iran putting some brakes on its programme in exchange for a mild loosening of international sanctions. Now comes the hard part. The two sides have pledged to reach a comprehensive agreement by the end of July that could, in theory, let Iran off the hook for good and relieve fears of a nuclear arms race in the already messy Middle East.

The target date is ambitious, and not just because the technical issues are fiendish. Serious gaps remain between what Iran wants and what the P5+1 seeks. Worse, a decade of frustrating diplomacy has left a prickly legacy of distrust not only between the parties, but between rival, sniping political factions within both Iran and the West. In the past, cries of treachery from America's Congress or from Iranian hardliners have undermined progress towards a deal. Western governments worry that if the talks fail this time, it will be harder for them to corral the world into re-tightening sanctions than for Iran to re-accelerate its programme. President Hassan Rohani of Iran faces tricky tests whatever the outcome of the talks. He will either have to explain why a 30-year effort, which has cost Iran upwards of $300 billion by some estimates, must be radically scaled back, or he will have to warn his people to expect tougher times and deeper isolation from the rest of the world.

Despite all this, analysts point to reasons for hope. Iranian consumers and businesses have been badly squeezed by sanctions. Even hardened Iranian xenophobes recognise that promises of sanctions-relief and reduced tensions with the West were crucial to Mr Rohani’s election victory last June. The extra wiggle room has already enabled Iran’s leaders to make unprecedented concessions, such as granting greater leeway to international inspectors and sharply scaling back uranium enrichment. The P5+1 countries, for their part, now recognise the importance to Iran of saving face. Calls to dismantle or scrap parts of the nuclear programme have been rephrased as plans to convert controversial facilities to different uses. Although the threat of sanctions still hangs over Iran, Western negotiators focus now more on potential rewards than punishments.

The rewards of a comprehensive deal could be huge, and not only for Iran. The country’s immense resources in oil and gas have suffered decades of underinvestment, while its large, relatively educated population represents a potentially important unexploited market. The nuclear issue has heightened a range of tensions across the Middle East, not only between Iran and Israel but between Shia Muslims championed by Iran and Sunni Muslims led by Saudi Arabia. Iran has long insisted that its nuclear programme is benign. Western governments have long declared that they seek only proof of this, not to impoverish Iranians or to overthrow the Islamic Republic. It is time for both sides to prove they mean what they say.