Hidden Imam
The twelfth Shia imam, believed to have gone into hiding in 874 and to be alive still, whose absence left a question about who may legitimately rule.
The largest branch of Shia Islam is named after a man who has not been seen in over eleven hundred years. Twelver Shia, roughly eighty-five percent of all Shia and the state religion of Iran, hold that the twelfth in the line of imams descended from Ali did not die but was concealed by God, remains alive, and will return to fill the earth with justice. Everything distinctive about Shia political thought, including quietist withdrawal from politics and the Islamic Republic of Iran, follows from working out what to do in the meantime.
The disappearance
Shia Islam holds that religious and political authority passed after Muhammad through his cousin and son-in-law Ali and then through a designated line of his descendants, the imams: sinless, divinely guided, and the rightful leaders of the community. In practice the imams lived under surveillance by hostile caliphs, and most are believed by their followers to have been poisoned.
The eleventh, Hasan al-Askari, died at Samarra in Iraq in 874 under close Abbasid watch. His followers said he had left a young son, Muhammad, born around 869, whose existence had been kept secret to protect him and who had now been hidden by God. For roughly seventy years, the period called the Minor Occultation, four successive agents claimed to pass messages between the community and the concealed imam. In 941 the last of them died, announcing a final letter: there would be no more agents. That began the Major Occultation, which continues.
The problem of the meantime
The theology created an awkward political vacuum. If the only legitimate ruler of Muslims is the imam, and the imam is absent, then every government in the world is at best provisional and at worst a usurper. For most of Shia history the practical answer was quietism. Believers endured whatever ruler they had, Shia clerics confined themselves to law, teaching, and the collection of religious taxes, and legitimate politics was deferred until the return.
That left an opening that ambitious men repeatedly walked through. The Safavid shahs who forcibly made Iran Shia in the sixteenth century claimed descent from the imams and styled themselves the Hidden Imam's representatives. Over the centuries the senior clergy expanded their own claim to be his general deputies, competent to judge, to collect his share of the alms, and to guide the faithful in his absence.
The radical move came in 1970, when Ruhollah Khomeini argued in lectures published as Islamic Government that deputyship extended to rule itself: if the imam's law must be enforced and the imam is absent, then the most learned jurist must govern. That doctrine, velayat-e faqih, guardianship of the jurist, is the constitutional basis of the Islamic Republic of Iran and the reason its supreme leader is a cleric rather than a president. Many senior Shia clerics, notably in Najaf in Iraq, have never accepted it, and the argument between quietist and activist Shi'ism is a live political fault line from Baghdad to Beirut.
Why it still matters
The expectation of the Mahdi's return also gives Shia politics a powerful and dangerous idiom. Iranian presidents have invoked his imminent coming; movements from Iraq's Mahdi Army to occasional messianic claimants have borrowed his name. And Twelvers are not the only Shia: Ismailis and Zaydis split from the line at earlier imams and reject the whole twelfth-imam framework, which is why they developed very different politics.
A doctrine born of persecution and defeat, the insistence that the rightful ruler exists but is hidden, turned out to be one of the most adaptable ideas in Islamic history. It has justified staying out of politics entirely and seizing a state outright, and the same clerical establishment has used it for both.