TEHRAN: It is the hard-fought central pillar of his presidency, an election pledge delivered, but Hassan Rouhani may yet find it difficult to capitalise on Iran's nuclear deal with world powers.
The agreement, finally implemented Saturday in Vienna, consumed Rouhani's first two-and-a-half years in office but it will lift sanctions that had crippled Iran's economy.
Having ended the 12-year international crisis over Iran's nuclear programme, Rouhani wants to bolster his position at home, where Iranians want to see concrete economic improvements.
If candidates aligned with the moderate president make gains in parliamentary elections on February 26 they could shift the balance of power away from conservatives, allowing him to enact some social and political reforms.
In Rouhani's favour is a high approval rating – more than 60 percent, analysts say – but his fate remains tied to the nuclear deal.
A win for a Republican in November's US presidential election could see the agreement fall apart.
"If sanctions are removed with no problems, Rouhani will benefit as he will be seen as a good politician who kept his promise," Foad Izadi, a politics professor at Tehran University, told AFP.
"But if what is happening in Congress continues, and the deal unravels without positive results, Iranians will reconsider what Rouhani did. They will be able to ask him: what happened?'"
Only in the United States have politicians spoken of ripping up the agreement. The other five powers involved – Britain, China, France, Russia and Germany – remain squarely behind it.