Although optimism is always in short supply in the Middle East, there appear to be early positive signs emerging from the Iranian nuclear negotiations. The election of President Rouhani has proven to be the circuit-breaker everyone needed after the abrasiveness of the Ahmadinejad administration.

The Washington Post has even been bold (or more likely well-informed) enough to put some flesh on the bones of the proposal, and reports that Iranian Foreign Minister Zarif (pictured with EU foreign policy chief Catherine Ashton) has canceled his trip to Italy have given weight to rumours that there may be movement at the negotiating station. Zarif's latest comments ('It is possible to reach an understanding about an agreement before we close these talks tomorrow evening') reinforce that sense.

There will be some regional states nervous at the prospect of an Iran that is acting responsibly and giving ground on nuclear negotiations. One group that should be worried is the Syrian opposition. Both pre- and post-Shah, Iran has always believed that its size, history and culture demand that it have influence commensurate with the way it sees itself. The ethnic, linguistic and above all religious differences it has with the Arab world have always stymied that aspiration, which is why it likes to exert influence indirectly through its allies and proxies.

The loss of Syria as an ally would have immediate strategic consequences for Tehran, which is why it is not unreasonable to see a scenario in which Tehran demands the continued presence of Assad or a like-minded ruler in Damascus as one of the real prices for substantive cooperation on the nuclear issue.

Tehran certainly needs relief from the crippling sanctions, but it has adapted to them over more than a decade. It will be harder to adapt to the loss of Syria. If the nuclear negotiations continue to look promising then it will be interesting to see the ways in which diplomatic positions on Syria shift in substance, if not in words. The Iranians always drive hard bargains, after all.