In 1979 the dictatorial regime of Shah Muhammad Reza Pahlavi was forced to relinquish power. In its place, Iran was transformed into an Islamic republic, led by Ayatollah Ruhollah Khomeini until his death in 1989.
The Iranian political system is based on the 1979 constitution and principle of shariah, or Islamic law. Ultimate authority is vested in the Wali Faqih, a spiritual leader appointed by the Shiite clergy who reflects the will of God. An elected president is the chief executive and reflects the will of the people. The 290-member Islamic Consultative Assembly (Majlis Shura-ye Islami, commonly referred to as the Majlis) constitutes the legislative branch of government. All candidates for the Majlis must be recommended to the voters by legitimate Islamic political groups and approved by an Islamic screening committee. All legislation from the Majlis must be approved by the 12-member Council of Guardians, appointed by the religious leader and the Supreme Judicial Council. The Council of Guardians, however, can be bypassed by a resolution of the Expediency Council. This discretionary council, whose members are elected by the supreme leader, rules on legal and theological disputes between the Majlis and Council of Guardians. It is charged with ruling in the best interest of the country by establishing a balance between different interpretations of the tenets of Islamic law.
The president, elected for four years by popular vote, is the head of the cabinet and the civilian part of the executive branch. Thus, the government combines the authority of the supreme Shiite jurisconsult with the elected president and Parliament, producing a complex system of religio-juridical checks and balances. The entire system is based on a balance of power between the different factions of the ruling clerics. The supreme leader (Ali Khamenei) represents the conservatives, but the Majlis speaker, Mehdi Karubi of the Militant Clerics' Association (elected speaker unopposed in May 2000), represents the reformist coalition.