The killing of Iran's Supreme Leader Ayatollah Ali Khamenei has pushed the Islamic Republic into one of the most consequential transitions in its history. While air strikes continue and regional tensions rise, Iran's political system has activated constitutional mechanisms designed for precisely such a moment.

Despite the shock to the apex of power, the authorities have moved swiftly to project continuity. The structure of the Islamic Republic, a complex system combining elected institutions with clerical oversight and powerful security bodies, remains formally intact.

"An aggression and a war from outside – from Israel in particular – triggers support and unity among the people, and even within certain opposition groups... some would set aside their differences with the regime and try to support it," explains Ibrahim Freyhardt, is Associate Professor in International Conflict Resolution at the Doha Institute for Graduate Studies.

How the Iranian government currently operates

Iran's political system is defined by a dual structure: republican institutions elected by popular vote, operating alongside clerical bodies rooted in the country's post-1979 constitutional framework.

At the top sits the Supreme Leader, who oversees the armed forces, judiciary and key state institutions. Beneath that office is an elected president and parliament, alongside unelected oversight bodies such as the Guardian Council.

Following the Supreme Leader's death, Article 111 of the constitution has been invoked. It authorizes a temporary leadership council to assume the duties of governance until a successor is chosen.

That three-member interim body – consisting of President Masoud Pezeshkian, Judiciary chief Gholam-Hossein Mohseni-Ejei, and Guardian Council member Ayatollah Alireza Arafi – is responsible for carrying out the formal functions of the Supreme Leader during the transition.

However, due to the onging conflict, operational authority has shifted in practice towatds the National Security Council, which determines the national defense and security politcies and the Islamic Revolutionary Guard Corps (IRGC) which plays a central role in military command and strategic decision-making.

The IRGC oversees ballistic missile forces, commands the Quds Force responsible for regional operations, manages intelligence capabilities and conducts military operations in coordination with other state bodies. The National Security Council, however, acts as a coordinating mechanism across institutions.

Even as military pressure continues, the activation of these constitutional provisions is intended to ensure that governance structures remain functional.

How the next Supreme Leader will be selected

Under the constitution, a new Supreme Leader must be chosen within three months.

Responsibility for selecting and electing the new leader rests with the Assembly of Experts, which is an 88-member clerical body elected by popular vote for eight-year terms. The Assembly is empowered to appoint, supervise and, if necessary, dismiss the Supreme Leader.

"The Assembly of Experts will meet to select and elect a new leader but that will not be immediate, because they will not want to risk the assassination of the newly elected leader," Elijah Magnier, military and political analyst based in Brussels, told Al Jazeera English.

It is also important to note that there is an important structural feature: candidates for the Assembly of Experts must be vetted and approved by the Guardian Council. That 12-member body is itself closely linked to the leadership structure – six members are appointed directly by the Supreme Leader, while the other six are nominated by the judiciary and approved by parliament. The judiciary chief is also appointed by the Supreme Leader.

In effect, the late leader had significant influence over the institutional framework responsible for selecting his successor.

The Assembly's deliberations are conducted behind closed doors. Voting is not made public, and the process traditionally unfolds without official disclosure of internal discussions. 

While the constitution provides a three-month window, ongoing strikes and security concerns may complicate how and when the Assembly formally convenes. For now, the interim council continues to exercise authority.

Khamenei never publicly named a preferred successor and in practice the decision will likely be made by the most senior figures in the Islamic Republic who have wielded power under Khamenei for many years. The recommended successor would then have to be approved by the assembly.

What powers does the Supreme Leader hold?

The Supreme Leader is the highest authority in Iran's political system.

The office holds constitutional authority over:

- Command of the armed forces

- Appointment of senior military commanders

- Appointment of the head of the judiciary

- Appointment of half of the Guardian Council

- Oversight of state broadcasting

- Broad authority to determine general policies of the Islamic Republic

The Supreme Leader also has decisive influence over foreign policy and national security strategy, particularly through oversight of the armed forces and coordination with the IRGC.

While Iran has an elected president and parliament, their authority operates within parameters set by the Supreme Leader and overseen by clerical institutions.

For nearly four decades, the office functioned as the central axis of political and security power. The current transition tests whether that authority can be transferred smoothly during the ongoing conflict.