UPDATE 0700 GMT: The Assembly of Experts has averted a possible challenge to the future of the Supreme Leader’s position, electing the conservative Ayatollah Mohammad Yazdi as chair.

As we were posting this analysis, Fars posted the newsflash that Yazdi had been elected with 47 votes from the 86-member Assembly. Former President Hashemi Rafsanjani — who has proposed replacing the Supreme Leader with a Council after Ayatollah Khamenei’s death — received 24 votes.

Yazdi, a member of the Guardian Council, is former President of the Society of Seminary Teachers of Qom, Vice President of the Assembly of Experts, and head of judiciary.

More than 80 members of the Assembly of Experts are gathering in Iran for what may be one of the most significant votes in the history of the Islamic Republic.

The immediate issue is the selection of a chairman to replace Ayatollah Mahdavi Kani, who died last October after a heart attack and lengthy coma. However the vote — likely to feature former President Hashemi Rafsanjani attempting to regain the chair — could have implications far beyond the Assembly.

The significance is in the Assembly’s power to name and, nominally, to replace the Supreme Leader. Rafsanjani has said — repeating the statement in an interview last month — that he favors replacing the Supreme Leader with a council once Ayatollah Khamenei passes away.

With the Supreme Leader likely suffering from cancer, feeding rumors in the past week of terminal illness and even death, Rafsanjani’s proposal has taken on even greater weight.

Rafsanjani has not yet confirmed that he is standing in the election; however, hardliners have been concerned by the prospected and attacked the former President for months. They have accused him of involvement in “sedition”, the term used for the mass protests after the disputed 2009 Presidential election. They have continued to pressure his family, notably his son Mehdi Hashemi, on trial over long-standing financial and political charges.

The State broadcaster IRIB has joined the campaign, broadcasting footage of a demonstrator declaring, “Death to America, Death to Israel, and Death to Hashemi Rafsanjani”.

However, Rafsanjani’s opponents have struggled to find a candidate to oppose him in the vote. Some possibilities — such as Ayatollah Mesbah Yazdi, leader of the hardline Endurance Front, and Guardian Council head Ayatollah Ahmad Jannati — might not have enough support in the Assembly. A “compromise” possibility is Ayatollah Mahmoud Hashemi Shahroudi, a former head of judiciary who is close to the Supreme Leader and a friend of Rafsanjani; however, that option appears to have receded in recent weeks.

On Monday, the Green Movement got involved in the election. Former Deputy Interior Minister Mostafa Tajzadeh, imprisoned since 2009 for his role in the protests for reform, wrote Rafsanjani to ask him to ensure that a hardliner does not take charge of the Assembly. He asked the former President not to let his son’s legal case get in the way.

Ayatollah Ali Dastgheib also made a statement, implicitly supporting Rafsanjani and asking the Assembly for effective supervision of the Supreme Leader and Guardian Council. He also criticized the Assembly’s silence over the 4-year detentions of opposition leaders Mir Hossein Mousavi and Mehdi Karroubi: “Why should the servants of the nation be under house arrest while the thieves of the national treasury are hoping to become President again?”

Meanwhile, some hardliners returned to the “compromise” option of Ayatollah Shahroudi. Tehran Friday Prayer leader Ayatollah Movahedi Kermani said it was “very likely” that Shahroudi would emerge as the chairman, a projection supported by other Assembly members.