Ending a tense 4-month siege of the sacred city of Najaf, the U.S. military rolls toward Shiism's holiest shrine—the magnificent golden-domed Imam Ali Mosque—where the rebel Shiite cleric Muqtada Sadr and his black-clad "Army of the Mahdi" gather feverishly around the tomb of the Prophet Muhammad's son-in-law, Ali, convinced that the End of Days is at hand and ready to fight to the death both the American occupiers and the infidel Sunni establishment of Iraq.
Sometimes trying to understand the current crisis in Iraq can be like preparing for a vocabulary exam. Who is the Mahdi and why does he have an army? Why is Najaf so sacred? What is an imam? Are the differences between the Shiah and the Sunni so deeply rooted that they could ultimately destroy the stability of Iraq?
To answer these questions one must begin not with Ali's tomb in Najaf, but with the barren plain of Karbala, where Ali's son, Husayn, along with most of the Prophet Muhammad's family, were brutally massacred in the year 680 by the forces of the Syrian Caliph, Yazid I.
When Ali died, the caliphate, or leadership of the Muslim community, had passed to the governor of Syria, a man named Muawiyah, in a complicated power-sharing agreement that ensured the title would once again belong to the family of the Prophet upon Muawiyah's demise. However, after having transformed Muhammad's small community of faith into a dominant, rapidly expanding, and ethnically Arab kingdom of enormous wealth and power, Muawiyah had no intention of relinquishing his rule to a small band of religious purists living in the distant Arabian Peninsula. He therefore named his son Yazid heir to his throne.
To those who believed that the leadership of the Muslim community should have never left the Prophet's family in the first place, this was an intolerably impious act. Throughout the Empire, but particularly in the volatile regions of Iraq and Iran, a massive contingent of mostly non-Arab Muslims calling themselves the Shiatu Ali ("the Partisans of Ali") rose up in revolt. The partisans sent a message to Ali's eldest surviving son, Husayn, to come to Kufa, the center of the rebellion in Iraq, to lead them in battle against the evil usurper, Yazid.
Husayn agreed and prepared his family to march from their home in Medina to Kufa. They never made it. Having already crushed the Kufan rebellion, Yazid's army intercepted Husayn and his entourage at Karbala and, over a period of 10 days, massacred nearly every last member of the Prophet Muhammad's family.
The events at Karbala split the Muslim community into two major factions: those who considered Yazid the legitimate caliph, and those who believed that the rightful heirs to the Prophet's mantle had been unjustly removed from power. Yet while Karbala signaled the end of the political aspirations of the Shiatu Ali and the beginning of the world's first Muslim empire, there was a far greater significance to the events than anyone could have imagined at the time.
Four years after the massacre, a handful of the Shiatu Ali in Kufa gathered secretly at Karbala, not only to mourn the death of Husayn but also to atone for their failure to aid him at his hour of need. This concept of lamentation as penance was an unprecedented phenomenon in Islam. Indeed, as more and more partisans began gathering at Karbala, the Shiatu Ali gradually transformed from a failed political faction who aimed to restore leadership to the Prophet's family into a wholly new religious sect—Shiism, a religion founded on the model of the righteous believer who, like Husayn, willingly sacrifices himself in the struggle for justice against tyranny and oppression.
Karbala launched a series of religious innovations in Islam that widened the gap between the Shiah and the mainstream, or orthodox, Sunni. Chief among these was the notion of atonement through sacrifice, a concept that existed in many religions—including Christianity and Judaism—but not in Islam. It is said that "a tear shed for Husayn washes away a hundred sins." The Shiah believe Husayn's martyrdom at Karbala, like Jesus' sacrifice at Gethsemane, was a conscious decision predetermined by God before the beginning of time. They therefore celebrate his martyrdom every year with 10 days of festivities that include passion plays dramatizing the events of Karbala and funerary processions in which participants flog themselves with chains or beat their breasts in contrition.
Most of the Sunni world condemns such acts of ritual devotion as contrary to the original principles of Islam. The Sunni are particularly offended by the Shiite notion that salvation requires any kind of intercession, something the Quran absolutely rejects. Since only God can forgive sins, the Sunni consider any intermediary between the worshipper and the divine to be a desecration of the Prophet's message.