The most important result of the negotiations on Iran’s nuclear programme turned out to be that both Tehran and Washington could claim they had won some ground in the talks.

Iran and the P5+1 reached what the US called the “parameters” of Joint Comprehensive Plan of Action (JCPOA) – a list of objectives Tehran would have to reach under a final agreement targeted for the end of June.

This non-binding agreement hammered out in Lausanne allowed Mohammed Javad Zarif and John Kerry to return home with news that progress had been made in reaching an agreement, but their messages to domestic audiences differed substantially.

Zarif arrived in Tehran rightly claiming that he had negotiated to end sanctions against the Iranian economy while keeping Iran’s centrifuges spinning – albeit at a reduced capacity.

But the Iranian foreign minister also said that sanctions will be terminated as soon as the JCPOA is signed and nuclear inspectors enter Iran, and that the measures could not be reinstated.

In the US interpretation, sanctions would be “suspended” after the International Atomic Energy Agency (IAEA) has verified Iran has met its targets and could “snap back” at any time if commitments are not met.

The US parameters document makes the process of the sanctions relief uncertain with the timeline for the IAEA to complete its inspections unclear.

In the aftermath of the Lausanne talks, Zarif accused the Obama administration of misleading the American people in its statement on the agreement outline.

Although this obstacle is not insurmountable, it is a major issue that the parties need to agree on before a comprehensive agreement can be signed.

Obama also faces domestic challenges to the deal and must prevent the US Congress from vetoing the deal. The president faces a real threat if enough Democrats join the Republican Party in opposing the White House on the issue.

Iran is also expected to face some opposition domestically from conservative clerics, but it is expected that the head of state, Supreme Leader Ali Khamenei, would back an accord as laid out in the framework agreed in Lausanne.