An interim international deal on Iran’s nuclear programme could tilt the balance of power in the Middle East towards Tehran after two years of regional unrest that have weakened leading Arab nations.
Sunday’s agreement opens the way for a thaw in US-Iranian confrontation that has lasted almost as long as the US-Soviet Cold War, alarming Israel and Gulf Arab rulers who fear a new regional hegemon deeply hostile to their interests.
The deal to curb but not scrap Iranian uranium enrichment, which the West has long believed was meant to develop a bomb, has implications far beyond weapons proliferation.
For some Gulf states, which see Tehran as a regional troublemaker, and for Israel, which regards Iran as a mortal threat, the Geneva agreement means they have failed to dissuade Washington from a course they suspect will end in tears, such is their distrust of the Islamic Republic.
Iran will grow richer and stronger through the easing and eventual lifting of sanctions that have shackled its economy, emboldening its hardline rulers to step up support to Shiite allies in Arab countries, critics of the deal say.
In contrast, supporters of the accord say a rapprochement between two powers so long at odds could help stabilise the region and reduce sectarian strains that have set Shiites and Sunnis against each other.
With the historic Arab power centres of Egypt, Syria and Iraq all weakened by uprisings and sectarian strife, a new start with Tehran has emerged as an enticing potential win for a US administration in search of a foreign-policy success.
Rami Khoury, of the American University of Beirut, described the interim deal restricting Iran’s nuclear work as a “very good thing” that could eventually lead to rapprochement between Tehran’s clerical rulers and Gulf states.
“If the negotiations continue on and keep working, and the sanctions are slowly removed, it will revive Iran’s economy, and eventually its liberal movement and I think we will slowly see social and political progress in the country,” Mr Khoury said.
“In the short run it encourages cooperation between the United States and Iran to try to deal with Syria and stop the violence there. Right now there is a common threat developing, the [Sunni militants] who will bomb the Iranians, bomb the US, as we’ve seen, so they’re everybody’s enemy right now.”
Experts say Gulf countries will try to piece together a diplomatic and security strategy with like-minded countries to reduce their vulnerability to a resurgent Iran.
At the heart of Gulf concerns is a belief that the moderate Iranian officials who negotiated the nuclear deal are not the men in charge of what they see as Shiite meddling in Sunni Arab countries.
Gulf Arabs cite as a prime example Iranian support for Syria’s president, Bashar Al Assad, member of a sect that is an offshoot of Shiite Islam, who has waged a war against mostly Sunni rebels for more than two years.
A high-level Gulf Arab official close to the Saudi government said the kingdom’s attitude continued to be characterised largely by “suspicion”, based on Iranian involvement in Syria, Yemen and Bahrain.
“The atomic arsenal is not their only arsenal – it is the mischief arsenal they have that worries us,” he said.
The disclosure that senior US officials held secret bilateral talks with Iranian counterparts in recent months to prepare for the nuclear agreement may exacerbate Gulf leaders’ fears that Washington is willing to go behind their backs to do a deal with Iran.
Many Gulf Arabs suspect that the commercial imperatives that have driven decades of US engagement with them are similar to those driving US outreach to Tehran – business.
In addition, some Gulf Arabs fret that a United States increasingly self reliant in energy thanks to domestic shale gas might be less committed to guarding the Strait of Hormuz.
Sami Al Faraj, a security adviser to the Gulf Cooperation Council, said GCC governments would now work diplomatically and on the security level to ensure they were adequately protected against any resurgent Iranian ambitions.
Gulf Arabs felt slighted by the deal, he suggested.
“Iran is sitting at the high table. We are left with the leftovers.”
He added: “We will acquire more weapons ... We are going to check if our shopping list is adequate to respond to this. We are going to rally other nations that are hurt by this action into a unified diplomatic campaign.”
Some analysts speculate that Washington’s need to protect what could become one of its few diplomatic achievements in the region will mean that it will do whatever it needs to keep the Iranian thaw on track.
“Now, the US is even less likely to put serious pressure on Iran over their support of the Assad regime during the negotiations,” said Shadi Hamid of the Brookings Doha think tank.
“And, obviously, with everyone’s attention on Iran, Assad has cover to do pretty much whatever he wants.”