​the authority of clerics in the iranian theocratic political system comes from
Politics of Iran According to the constitution, the Guardian Council oversees and approves electoral candidates for most national elections in Iran. The Guardian Council has 12 members, six clerics, appointed by the Supreme Leader and six jurists, elected by the Majlis from among the Muslim jurists nominated by the Head of the Judicial System, who is appointed by the Supreme Leader. According to the current law, the Guardian Council approves the Assembly of Experts candidates, who in turn supervise and elect the Supreme Leader.
Iranian Revolution The Iranian Revolution (Persian: انقلاب ایران‎, translit. Enqelāb-e Iran; also known as the Islamic Revolution or the 1979 Revolution)[3][4][5][6][7][8] refers to events involving the overthrow of the Pahlavi dynasty under Mohammad Reza Shah Pahlavi, who was supported by the United States,[9] and eventual replacement of 2,500 years of continuous Persian monarchy with an Islamic Republic under the Grand Ayatollah Ruhollah Khomeini, the leader of the revolution, supported by a wide range of people including various Islamist and leftist organizations[10] and student movements.