Rafsanjani, widely regarded as a pragmatist, was elected to head the Assembly of Experts, a clerical body that selects the nation’s supreme religious leader. The new position further enhances his standing and was viewed by many analysts as at least a temporary obstacle to the hard-line conservatives running the government.

News of Rafsanjani’s ascension came during a turbulent week of Iranian politics and indicated that the leadership may be seeking to counter international criticism. President Mahmoud Ahmadinejad has been defiant in promoting the country’s nuclear aspirations, but Tehran also made a leadership change in the Revolutionary Guard and permitted an American scholar facing allegations of espionage to leave the country.

The election of Rafsanjani amid this tenor is big news as the rational and moderate side of the [regime] will be more empowered,” said Saeed Albehdashti, an activist with the reform-minded Imam Khomeini Followers Front.

Some analysts, however, suggest that Rafsanjani, seen as a clever political operative who understands the West, will have limited political latitude and remain answerable to supreme leader Ayatollah Ali Khamenei, who in recent years has increased his power and his belligerence toward Washington.

Rafsanjani’s remarks immediately before his election to head the assembly underscored the sensitive role he may play in the balance between reformers and hard-liners, especially in protecting the country’s nuclear program, which Washington charges is aimed at producing an atomic bomb.

US officials “made a big issue of the nuclear issue and they are mobilizing public opinion,” Rafsanjani said. “Because of the dangers threatening us, we should pay attention to the supreme leader’s decree for national unity and Islamic cohesion. We should not let ourselves be provoked and give an excuse for the enemy.”

Michel Potocki, an expert on Iran’s legal system and a scholar at the Sorbonne in Paris, said that Rafsanjani “symbolizes a more moderate faction opposed to Ahmadinejad faction. But I’m not sure he will be capable of making any important decisions. Everything depends on the supreme leader, after all”.

Rafsanjani won 41 of the votes cast by 86 senior clerics to become chairman of the Assembly of Experts. The next biggest vote-getter was Ayatollah Ahmad Jannati, a religious extremist who garnered 34 of the ballots. Unlike Rafsanjani, Jannati believes the nation’s authority should come from God, not democratic elections. Rafsanjani also heads another pivotal body, the Expediency Council, which mediates legislative and constitutional matters.

How Rafsanjani’s new political role factors into Iran’s larger international agenda is crucial to pragmatists and moderates. He had been marginalised in recent years, and it remains to be seen whether his seemingly rising stature will have much effect in terms of curtailing the sweeping power of hardliners.

The Assembly of Experts’ main focus is to select the supreme leader; its power outside that role “has not been taken practically or traditionally serious,” said Ahmad Shirzad, a physicist and political reformist. But, he added, most of the assembly consists of influential traditionalist religious leaders who lead Friday prayers across the nation. The vote for Rafsanjani “indicates that even the traditionalists of the system are tilting toward moderation and pragmatism”, Shirzad said.