 Guardianship of the Islamic Jurist in the Islamic Republic of Iran is represented not only in the Supreme Leader, who must be a cleric, but in other leading bodies, particularly the Assembly of Experts whose members must be clerics, the Council of Guardians, half of whom must be clerics, and the courts.Friday prayer leaders are appointed by the Supreme Leader as well.Quietist scholars of Qom and Najaf hawzas criticise Iranian system of governance, while the Big Four, among them Grand Ayatollah Ali al-Sistani, oppose the concept actively.