RELATIONS between Iran and the secular West have been so fraught that expectations raised over the interim nuclear agreement have to be heavily qualified.
The deal was not a breakthrough as plenty could still go wrong.
It was nevertheless a notable diplomatic achievement because sticking points did not sink the negotiations which, the world has learnt, had their genesis in secret Iran-United States contacts arranged by the Sultan of Oman.
A preliminary statement of intent probably best describes the agreement struck in Geneva with the United Nations' five veto members, plus Germany. If the process could be concluded on terms acceptable to all seven parties, one flashpoint of potential war in West Asia would have been taken out of the reckoning.
This is why the interlocutors must remain engaged, whatever the hurdles and doubts, to avert a dangerous conflict that could drag in Israel and Russia, besides the US.
Not surprisingly, the Geneva terms were interpreted differently in one critical aspect - the scope and direction of Iran's nuclear programme.
Seasoned negotiators know this is in the nature of history-making talks, whose initial aim is to ensure there will be a next round, and another, until all issues are nailed.
As to be expected, Iranian President Hassan Rouhani sold the deal to his people as a victory, declaring that the world now recognised Iran's right to nuclear enrichment for peaceful purposes. This, he said, was consistent with its status as a signatory to the Nuclear Non-Proliferation Treaty.
US Secretary of State John Kerry demurred just as forthrightly, saying the issue was to be determined in subsequent rounds.
Nuclear dismantlement or a partial continuance? These are not critical matters at this juncture, odd though it would sound.
There is time to settle on that later. What matters to Iran is economic recovery - a rollback of the boycotts and sanctions causing hardships that the spiritual leadership fears could inspire a people's revolt.
That conceivably would undo the rule of the ayatollahs.
To America, breaking down the mistrust that has frozen relations with Iran for three decades would reinforce its hold on West Asia, the better to exploit the energy riches and to advance its foreign policy goals.
These are seven-party talks which also include China and Russia, to provide a veneer of an international concert. But the process is essentially meant for the US and Iran to discover whether they can be natural allies.
The Islamic republic's balancing role in the religio-strategic landscape of West Asia could be crucial. If the US hopes to play a decisive role too in the region's geopolitics, it cannot act in isolation.
Get a copy of The Straits Times or go to straitstimes.com for more stories.