The sudden death of President Ebrahim Raisi is unlikely to drastically alter Iran’s foreign and domestic policies, but it has left a power vacuum.

As stipulated by the constitution, Raisi was replaced by his first vice president, Mohammad Mokhber, as interim president before presidential elections are held in 50 days. That said, Raisi was supposedly being groomed to succeed an aging Ali Khamenei as the supreme leader, the Islamic Republic’s ultimate power broker and decision-maker.

The Iranian supreme leader serves for life and is the highest religious and political authority in the Islamic Republic. He is the commander in chief of the armed forces and oversees other key institutions such as the judicial branch and state media. He also supervises the Guardian Council, which has the power to vet electoral candidates and veto parliamentary legislation. In this capacity, the supreme leader has the final say on foreign policy and different areas of domestic policy.

As a scholar of Iran’s domestic politics and foreign policy, I have studied the process of who succeeds or gets elected to the position. This process has evolved during the Islamic Republic’s nearly 50-year history and is more a function of politics than religion.

The history of succession

Since the Iranian Revolution of 1979, there have been two supreme leaders – Ayatollah Ruhollah Khomeini, who ruled between 1979-1989, and Ayatollah Ali Khamenei, who succeeded him.

In addition to being a revolutionary and charismatic leader, Khomeini was a grand ayatollah and source of emulation, or “marja’ al-taqlid.” A grand ayatollah is among a select few of the highest-ranking clerics, considered a “sign of God,” in Twelver Shiism, the largest branch of Shiism and the state religion of Iran. These clerics have the authority to make legal decisions for their lay followers and for lower-ranking clerics.

While Khomeini came into power as a religious cleric and revolutionary leader in February 1979, it was not until the Islamic Constitution was approved through a referendum in December of that year that the position or office of supreme leader was officially established. It was inspired by Khomeini’s concept of the Guardianship of the Jurist, or the idea that a senior cleric should supervise the state in accordance with Islamic law.

The electoral facade

In 1982-83, when Khomeini was the supreme leader and Khamenei was the third president, the position or office fell under the purview of the Assembly of Experts, as enshrined in articles 107 and 111 of the constitution.

The Assembly of Experts is a body that comprises over 80 members who serve eight-year terms and are authorized to elect, supervise and, if necessary, dismiss the supreme leader. Although the members are elected by a popular vote, they are first vetted by the Guardian Council, much like presidential and parliamentary candidates.

It should be noted that the members of the Guardian Council are appointed by the supreme leader and the chief justice, or head of the judiciary, who is also appointed by the supreme leader. Therefore, through the council, the supreme leader approves the candidates, who are potentially elected to a body that oversees him, making the process far from free and fair.

As with the last election for the Assembly of Experts in March 2024, which had a historically low voter turnout of about 40%, the Guardian Council has disqualified many candidates.

This is particularly the case with moderates and reformists, who tend to oppose the supreme leader on various issues. For this reason, the assembly has not been known to seriously supervise or challenge the supreme leader, and its proceedings have remained strictly confidential or closed to the public.

The 1989 succession

Originally, the supreme leader was supposed to be a grand ayatollah and source of emulation. However, as Khomeini approached the end of his life in 1989, the constitution was amended so that a lower-ranking cleric like Khamenei could assume the position.

As a seminary student of Khomeini who was more interested in politics than religion, Khamenei ranked below an ayatollah. Within the Shiite clerical hierarchy, and like other Islamic scholars who studied under an ayatollah, he earned the title Hojjat al-Eslam, or “proof of Islam.”

After being appointed to succeed Khomeini, Khamenei’s rank was elevated overnight to a grand ayatollah. The reason for the appointment was that Khamenei, much like Raisi, was a longtime loyalist and regime insider, even though he lacked the charismatic and religious authority of Khomeini.

Until 1989, Grand Ayatollah Hussein-Ali Montazeri – a prominent theologian and revolutionary leader – was expected to take over as the supreme leader. That year, however, he was ultimately passed over by Khomeini and later placed under house arrest by Khamenei.

Montazeri succumbed to this fate because he had criticized the regime for its repression, especially the execution of thousands of political prisoners in 1988 by a committee of four prosecutors, one of whom was Raisi.

The situation with succession today

With only a single case serving as precedent, the succession process of the supreme leader seems to be far from formulaic and formalized.

Technically, the Assembly of Experts is responsible for electing the future supreme leader. As with other institutions, however, it is the supreme leader who ultimately exercises authority over the assembly and not vice versa.

Additionally, and because of the intervention of the Guardian Council, the Assembly of Experts and other institutions are currently controlled by hard-liners.

This scenario also applies to a Parliament that could once again authorize amending the constitution and altering the required qualifications of the next leader. It is critical for Khamenei that the Assembly of Experts and Parliament – the Majles – are controlled by hard-liners who are regime loyalists.

As with Raisi, and in the spirit of patronage or clientelism, hard-liners are often appointed to other positions inside the political and economic establishment by the supreme leader. Consequently, they owe their careers to him and tend to show their loyalty.

While political outcomes in the Islamic Republic are difficult to predict, the process of succession largely lies in the hands of the supreme leader and is at his discretion. As in 1989, it will be dictated or determined by Khamenei’s political and personal preferences rather than religious and ideological principles.

At the same time, it is safe to say that the hard-liners inside the Assembly of Experts and other institutions are not monolithic and do not all follow the agenda of the supreme leader. They presumably possess different opinions about who should succeed him, among other issues.

From my perspective, while the supreme leader may hold the upper hand inside the system, the selection of his successor will likely involve some consultation and consensus with hard-liners. Doing so will be essential to navigating a transition made more delicate by the death of the hard-line president and potential heir.

Eric Lob is affiliated with the Middle East Institute.