How Iran chooses its supreme leader, and who could be next?

Ayatollah Ali Khamenei’s death following joint U.S.-Israeli airstrikes has thrust Iran’s leadership into the urgent process of selecting a new supreme leader.

Under Iran’s constitution, the supreme leader is appointed by the Assembly of Experts, an 88-member clerical body elected by the public every eight years. Candidates for the Assembly are first vetted by the Guardian Council, tightly controlling who can run.

When the position becomes vacant, the Assembly convenes to deliberate and select a successor. The decision requires a simple majority vote.

In the interim, a provisional three-member leadership council assumes the supreme leader’s duties until a replacement is formally appointed.

On Sunday, local media reported that the temporary council comprises President Masoud Pezeshkian, Judiciary Chief Gholam-Hossein Mohseni-Ejei and Ayatollah Alireza Arafi, who serves as the Guardian Council’s representative.

The council’s authority is strictly transitional, while the Assembly of Experts retains sole constitutional power to choose Iran’s next supreme leader.

On Polymarket, traders are pricing Mohseni-Ejei as the narrow frontrunner at roughly 18%. Other top contenders include Arafi and Iranian cleric Hassan Khomeini.

The “Position abolished” outcome is trading close behind, suggesting that while markets still lean toward an individual successor, there is meaningful speculation around a potential structural change to the office itself.

Here are some key contenders:

Mohseni-Ejei has been the Chief Justice of Iran since July 2021, overseeing the country’s judiciary and supervising legal policy across the Islamic Republic. 

Before that, he served as prosecutor-general from 2009 to 2014, was first deputy head and spokesperson of the judiciary from 2014 until 2021, and earlier held national security roles, including minister of intelligence from 2005 until 2009. 

He has also been a longtime member of the Expediency Discernment Council, a key advisory body to Iran’s leadership, and his career has spanned senior positions in both the judicial and security apparatus.

Khomeini is the grandson of Islamic Republic founder Ayatollah Ruhollah Khomeini, could theoretically serve as a bridge between the revolutionary system and reform-minded constituencies, said the Council on Foreign Relations.

CFR suggested that elevating someone like him might help preserve the core structure…