The Twelve Imams and the occultation of the Mahdi

Twelver Shia Islam counts a fixed line beginning with Ali, continuing through his sons Hasan and Husayn, and running through eight further descendants, among them Jafar al-Sadiq, the sixth, whose teaching gave the tradition its school of law and after whose death the Ismaili branch separated. The eleventh, Hasan al-Askari, died at Samarra in 874 under Abbasid surveillance, apparently without an acknowledged son.

Twelver doctrine holds that he had one, Muhammad al-Mahdi, concealed from birth for his protection. From 874 the Imam is held to have communicated with the community through four successive deputies, a period called the lesser occultation. In 941 the fourth deputy declared that no further deputy would be appointed and that a greater occultation had begun. The Imam is alive, hidden, and will return, with Jesus, to fill the earth with justice as it is now filled with tyranny.

Sunni Islam has its own expectation of a Mahdi as a future deliverer, but he is not identified with a particular living person and the doctrine has less structural weight. The Twelver version is closer in shape to the Jewish expectation of a messiah still to come than to either, in that a specific line and a specific person are named. It differs from the Christian claim in that the awaited figure is a guide and a restorer of justice, not a redeemer whose death effects salvation.

Claims to be the Mahdi, or to be his gate or representative, have periodically produced new movements. The Babi movement in nineteenth-century Iran, from which the Bahai Faith emerged, began with such a claim, and the Ahmadiyya movement in Punjab with another.

An absent Imam creates a practical problem that has shaped Twelver Islam more than any other doctrine. If religious authority belongs to the Imam and the Imam cannot be consulted, who decides?

The answer developed over centuries. Authority passed to the scholars, the ulama, as general deputies of the hidden Imam. The Usuli school, which prevailed decisively over its Akhbari rivals in the eighteenth century, holds that a qualified jurist may exercise independent reasoning, ijtihad, and that ordinary believers must follow a living jurist, choosing a marja al-taqlid, a source of emulation, whose rulings they observe and to whom they pay religious dues. Akhbaris had held that the traditions of the Imams suffice and that such reasoning is illegitimate. The Usuli victory gave Twelver Shiism a living, funded, independent clerical hierarchy of a kind Sunni Islam does not possess, centred on the seminaries of Najaf and Qom.

The extent of that authority is contested within the tradition. Ruhollah Khomeini argued that the jurist's deputyship extends to political rule, wilayat al-faqih, and the Islamic Republic of Iran was built on it after 1979. Many senior Shia jurists, including the most widely followed authority in Najaf, hold a narrower view in which the clergy guide but do not govern, and the quietist position has substantial support in Iraq and elsewhere. This is a live argument about the meaning of the occultation, not a settled doctrine.

The messianic charge also cuts both ways politically. Because the Imam's return will establish justice, any existing government occupies a provisional and in principle illegitimate position, an idea that has fuelled both revolutionary movements and a tradition of political withdrawal, depending on who was drawing the conclusion.