Q&A: How powerful is the Iranian president?

(Reuters) - Whoever wins Iran's presidential election on Friday will enjoy only limited power in the Islamic Republic's complex system of clerical rule and popular voting.

HOW DOES THE ISLAMIC REPUBLIC WORK?

In a referendum after the 1979 Islamic revolution, Iranians overwhelmingly approved the creation of an Islamic Republic to replace the U.S.-supported monarchy. Later that year they backed a new constitution for a hybrid political system combining elements of democracy with unelected religious leadership.

Thus, the elected president is completely subordinate to the appointed Supreme Leader. Similarly, the elected parliament is shadowed by the Guardian Council, a panel of 12 unelected clerics and Islamic jurists who have the power to reject any legislation deemed un-Islamic and to veto presidential and parliamentary candidates they consider unfit for office.

The result, Iran says, is Islamic democracy. Critics say it is a facade, with real power wielded only by unelected clerics.

HOW POWERFUL IS THE PRESIDENT?

In theory, the president's powers are second only to those of the Supreme Leader, a post occupied by Ayatollah Ali Khamenei since 1989. In practice, his freedom of action is also curtailed by a range of unelected bodies mostly controlled by hardline clerics. These bodies, including the Guardian Council, have backed President Mahmoud Ahmadinejad since he was elected in 2005, but thwarted his reformist predecessor Mohammad Khatami.

WHAT DOES THE PRESIDENT DO?

He is responsible for economic policy and, along with his cabinet of ministers, daily management of national affairs.

The president chairs the Supreme National Security Council, which coordinates defense and security policy. He can sign agreements with foreign governments and approve ambassadorial appointments. On bigger issues he defers to the Supreme Leader.

WHAT DOES THE SUPREME LEADER DO?

The Supreme Leader, appointed by an assembly of senior clerics elected by popular vote, has the final say in vital matters such as nuclear policy and foreign relations, especially any decision to repair ties with the United States.

He sets the broad outlines of domestic and foreign policy and directly controls the armed forces and intelligence agencies. He appoints the head of the judiciary, the state broadcasting company and other key posts. Personal representatives of the Leader are scattered through state institutions and regions.

(Writing by Parisa Hafezi; Editing by Alistair Lyon)