How does Iran's system of power work?

The United States is considering new military strikes against the Islamic Republic of Iran over its deadly suppression of protests this month. The complexities of Iran's ruling system, the ideological nature of its support base, and the power of its Revolutionary Guards make it hard to predict its resilience or vulnerability in the face of external attack, or what might come next.

The following explains how the system operates and who the main figures are in today's Iran:

WHY DOES IRAN HAVE A 'SUPREME LEADER'?

Iran's political system is based on the theory of vilayat-e faqih ("rule of the jurist"), which holds that until the return of the Shi'ite Muslim 12th Imam, who disappeared in the ninth century, power on earth should be wielded by a supreme cleric.

The first Supreme Leader, Ayatollah Ruhollah Khomeini, was the charismatic father figure of the 1979 Islamic Revolution who developed the model of a cleric standing above an elected government.

His successor, Ayatollah Ali Khamenei, has cemented that role since becoming leader in 1989. This has ensured he retains the ultimate say on all major policy decisions and has built a parallel system of rule, alongside that of the elected government, staffed with loyalists.

Khamenei's sway has often been wielded through the National Security Council headed by longtime adviser Ali Larijani. Other advisers to Khamenei, including former defence minister Ali Shamkhani and former foreign minister Ali Akbar Velayati, have also played prominent roles.

Khamenei, 86, has not named a successor and it's not clear who would replace him if he was killed or ousted.

His son, Mojtaba Khamenei, has at times been seen as a possible candidate. His predecessor's grandson, Hassan Khomeini, has been another, as have some older senior clerics.

IS IRAN A THEOCRACY?

Iran's clerical elite control powerful bodies that extend their influence throughout the political system.

The Assembly of Experts, made up of senior ayatollahs elected every eight years, is the body that appoints the supreme leader. The constitution also gives it power to question and even dismiss a leader, but it has never done so.

The Guardian Council - half appointed by the leader and half by the judiciary chief - can veto laws passed by parliament and disqualify election candidates, a mandate that has been used to block potential critics of Khamenei.

Another clerical body, the Expediency Council, appointed by Khamenei, resolves disputes between the elected parliament and the Guardian Council.

Iran follows Shi'ite interpretations of Islamic sharia law and its judges are also clerics under a judiciary chief named by Khamenei. The current head, Gholamhossein Mohseni Ejei, was sanctioned by Western countries for a violent crackdown on protesters in 2009 when he was intelligence minister.

Other influential clerics include Expediency Council head and former judiciary chief Sadiq Larijani, the brother of Ali Larijani; Assembly of Experts and Expediency Council member Mohsen Araki; and Tehran Friday prayer leader Ahmad Khatami.

However, not all clerics - even senior ones - are necessarily supporters of Iran's theocratic system or its current rulers. Some have been dissidents, others like former President Mohammed Khatami have unsuccessfully tried to reform and soften the existing system.

HOW POWERFUL ARE THE REVOLUTIONARY GUARDS?

Unlike the ordinary military, which comes under the Defence Ministry in the elected government, the Islamic Revolutionary Guards Corps answers directly to the Supreme Leader.

Formed soon after the revolution, the IRGC's role defending the Islamic system greatly expanded during the 1980-88 war with Iraq and it is now the strongest and best-equipped section of Iran's armed forces.

Over the decades, the Guards have extended their influence through the worlds of politics and business, gaining in power at home and abroad.

The Quds Force, an elite Guards unit, has spearheaded Iran's regional strategy of supporting affiliated Shi'ite groups across the Middle East, most notably in Lebanon and Iraq. That strategy was hard-hit by the U.S. assassination of Quds Force commander Qassem Soleimani in a 2020 air strike in Iraq, and by Israel's pummelling of Lebanon's Hezbollah in a 2024 war.

The Basij militia, a part-time paramilitary force under Guards control, is often used to quell protests inside Iran.

Since the early 2000s, the Guards' economic power has grown as its contracting company Khatam al-Anbiya won projects worth billions of dollars in Iran's oil and gas sector.

The targeted nature of Israeli strikes on senior Guards commanders last year and Hezbollah leaders in 2024 has raised questions over possible Western intelligence penetration in the corps' upper echelons.

However, Guards commander Mohammad Pakpour, his deputy Ahmad Vahidi, the IRGC's naval chief Alireza Tangsiri and current Quds Force commander Esmail Ghaani remain powerful figures.

IS IRAN ALSO A DEMOCRACY?

Iranians elect a president and a parliament to four-year terms. The president appoints a government that handles daily policy within parameters permitted by the Supreme Leader.

During the early years of the Islamic Republic the votes drew mass participation. But Guardian Council restrictions on candidates and a much-disputed election outcome in 2009 undermined trust among many voters, while the Supreme Leader's overarching role has reduced the scope for elected bodies.

President Masoud Pezeshkian, seen as a moderate, was elected in 2024 after a first-round vote with around 40% turnout, and a run-off in which about half the electorate took part. He defeated Saeed Jalili, a Khamenei loyalist and anti-Western hardliner who remains influential.

The parliament speaker since 2020 has been former Guards commander Mohammad Baqer Qalibaf.