This hopefulness is based on the emerging sense that a quid pro quo is feasible. While the details people imagine vary, in general terms the deal would involve Iran revealing the full extent of its nuclear efforts and limiting enrichment to what the amount and extent it really needs under tight international supervision. The international community would ease off on sanctions.
What is far less clear than the shape of a deal is whether politics in either Tehran or Washington will allow it to happen, as Zack Beauchamp speculated on Twitter last week. Europe, which leads the p5+1 (US, UK, France, China, Russia and Germany) talks with Tehran is useful to the process but will go along with whatever the Americans and Iranians decide.
Iran’s Supreme Leader, Ayatollah Khamenei, has been a major stumbling block in the past. He scuppered a deal a few years ago that would have supplied Iran with the enriched uranium it needs for a research reactor in exchange for shipping its own stockpile of 20% enriched uranium out of the country. Unquestionably more in charge than in the past, Khamenei and the Revolutionary Guards who support him need hostility with the West to maintain their increasingly militarized regime. A resolution–even a partial one–of the nuclear standoff may not be in their interest.
It might not please hawks in the U.S. Congress either. They want a complete halt to enrichment in Iran and don’t want to rely on international inspections that might be suspended or otherwise blocked. Improvement in relations with Iran would hinder their hopes for regime change there. It would also make it difficult to criticize Barack Obama in the runup to the election for his diplomatic outreach to Iran, which failed initially but with the backing of draconian international sanctions seems now to be succeeding.
The smart money is betting that both Tehran and Washington will want to string out the negotiating process past the U.S. election in November. This would be a shame if a deal really is possible before then. The world economy would look a lot brighter if oil prices, pumped up since winter by Iranian threats to close the strait of Hormuz, sank well below $100 per barrel. Improved relations with Iran could also have positive knock-on effects in Iraq and Afghanistan, where Iran (which neighbors both countries) has sought to make things hard for the Americans.
A nuclear deal could also free the American hand a bit in Syria, where Washington has been reluctant to act decisively because it needs Russia and China on board for the P5+1 effort. Of course it might also work in the other direction: Washington could decide to give a bit in Syria in order to get a nuclear deal with Iran. That would not be our finest moment.
PS: Julian Borger is, as usual, worth reading, in particular on how low the bar has been set for the Baghdad talks.