The passing of Supreme Leader Ayatollah Ali Khamenei, who held power for nearly 37 years, has cast a spotlight on the uncertain future of Iran.

The succession process gained urgency following Khamenei’s death in a targeted airstrike conducted jointly by the United States and Israel.

Here are the essential details:

Temporary leadership council

According to Iran’s constitution, a leadership council was established on Sunday to manage the nation’s affairs.

This council includes the current president of Iran, the head of the judiciary, and a Guardian Council member selected by the Expediency Council, which advises the supreme leader and resolves legislative conflicts.

The council comprises Iran’s reformist president, Masoud Pezeshkian, and the hard-line judiciary chief, Gholamhossein Mohseni Ejei. Together, they will “temporarily assume all the duties of leadership.”

Panel of clerics

Though the leadership council will govern in the interim, an 88-member panel called the Assembly of Experts “must, as soon as possible” pick a new supreme leader under Iranian law.

The panel consists entirely of Shiite clerics who are popularly elected every eight years and whose candidacies are approved by the Guardian Council, Iran’s constitutional watchdog.

That body is known for disqualifying candidates in various elections in Iran and the Assembly of Experts is no different. The Guardian Council barred former Iranian President Hassan Rouhani, a relative moderate whose administration struck the 2015 nuclear deal with world powers, from election for the Assembly of Experts in March 2024.

Khamenei’s son

Clerical deliberations about succession and machinations over it take place far from the public eye, making it hard to gauge who may be a top contender.

Previously, it was thought that Khamenei’s protege, hard-line President Ebrahim Raisi, may try to take the mantle. However, he was killed in a May 2024 helicopter crash.

That has left one of Khamenei’s sons, Mojtaba, a 56-year-old Shiite cleric, as a potential candidate, though he has never held government office.

But a father-to-son transfer in the case of a supreme leader could spark anger, not only among Iranians already critical of clerical rule, but also among supporters of the system. Some may see it as un-Islamic and in line with creating a new, religious dynasty after the 1979 collapse of the U.S.-backed Shah Mohammad Reza Pahlavi’s government.

Rare transition

There has been only one other transfer of power in the office of supreme leader of Iran, the paramount decision-maker since the country’s 1979 Islamic Revolution.

In 1989, Grand Ayatollah Ruhollah Khomeini died at age 86 after being the figurehead of the revolution and leading Iran through its eight-year war with Iraq. This transition now comes after Israel launched a 12-day war against Iran in June 2025 as well.

Vast powers

The supreme leader is at the heart of Iran’s complex power-sharing Shiite theocracy and has final say over all matters of state.

He also serves as the commander-in-chief of the country’s military and the powerful Revolutionary Guard, a paramilitary force that the United States designated a terrorist organization in 2019, and which Khamenei empowered during his rule.

The Guard, which has led the self-described “Axis of Resistance,” a series of militant groups and allies across the Middle East meant to counter the U.S. and Israel, also has extensive wealth and holdings in Iran.