It has come to this: the hatred between Iraq's warring sects is now so toxic, it contaminates even the memory of a shining moment of goodwill. On Aug. 31, 2005, a stampede among Shi'ite pilgrims on a bridge over the Tigris River in Baghdad led to hundreds jumping into the water in panic. Several young men in Adhamiya, the Sunni neighborhood on the eastern bank, dived in to help. One of them, Othman al-Obeidi, 25, rescued six people before his limbs gave out from exhaustion and he himself drowned. Nearly 1,000 pilgrims died that afternoon, but community leaders in the Shi'ite district of Khadamiya, on the western bank, lauded the "martyrdom" of al-Obeidi and the bravery of his friends. Adhamiya residents, for their part, held up al-Obeidi's sacrifice as proof that Sunnis bore no ill will toward their Shi'ite neighbors across the river.  Eighteen months on, one of the men who jumped into the river to help the Shi'ites says al-Obeidi "wasted his life for those animals." Hamza Muslawi refuses to talk about how many he himself saved, saying it fills him with shame. "If I see a Shi'ite child about to drown in the Tigris now," says the carpenter, "I will not reach my hand out to save him." In Khadamiya, too, the narrative about Aug. 31 has changed. Karrar Hussein, 28, was crossing the bridge when the stampede began. Ask him about al-Obeidi, and his cheerful demeanor quickly turns sour. "That is a myth," hisses the cell-phone salesman. "That person never existed at all. He was invented by the Sunnis to make them look good." Rather than jumping in to help, he claims, the people of Adhamiya laughed and cheered as Shi'ites drowned.  The bridge connecting the two neighborhoods is now closed for security reasons--just as well, since the chasm between them is too wide for any man-made span. Mortars fired from the cemetery behind Abu Hanifa, a Sunni shrine in Adhamiya, have caused carnage in the bustling markets of the western bank. There are more mortars going in the opposite direction; on a recent afternoon, the sound of an explosion on the Sunni side of the river is greeted with cheers by worshippers at a Shi'ite shrine in Khadamiya.  Those cheers are just one sign of how much venom has seeped into Sunni-Shi'ite relations in the year since their simmering conflict was brought to a boil by the bombing of Samarra's golden-domed shrine. The bloodlust is no longer limited to extremists on both sides. Hatred has gone mainstream, spreading first to victims of the violence and their families--the hundreds of thousands of Iraqis who have lost loved ones, jobs, homes, occasionally entire neighborhoods--and then into the wider society. Now it permeates not only the rancorous political discourse of Baghdad's Green Zone but also ordinary conversations in homes and marketplaces, arousing a fury even in those who have no obvious, pressing grievance. Neither Muslawi nor Hussein has suffered personal loss, but they are relatively able to tap into the same loathing that motivates the Shi'ite militias and Sunni jihadis. "The air has become poisoned [by sectarianism], and we have all been breathing it," says Abbas Fadhil, a Baghdad physician. "And so now everybody is talking the same language, whether they are educated or illiterate, secular or religious, violent or not."  Worse, there are clear signs that Iraq's malice has an echo in other parts of the Middle East, exacerbating existing tensions between Sunnis and Shi'ites and reanimating long-dormant ones. In Lebanon, some Hizballah supporters seeking to topple the government in Beirut chant the name of radical Iraqi cleric Muqtada al-Sadr, whose militia is blamed for thousands of Sunni deaths. In Sunni Arab countries like Saudi Arabia, Kuwait and Egypt, sympathy for Sunnis in Iraq is spiked with the fear, notably in official circles, of a Shi'ite tide rising across the Middle East, instigated and underwritten by an ancient enemy of the Arabs: Iran.  For those who follow Iraq from afar, the daily stories of sectarian slaughter are perplexing. Why are the Shi'ites and Sunnis fighting? Why now? There are several explanations for the timing of the outbreak of hostilities, each tied to a particular interpretation of how events unfolded after the fall of Saddam Hussein: flawed American postwar policies, provocation by foreign jihadis, retaliation by militias like al-Sadr's Mahdi Army, the ineptitude of Iraqi politicians and, lately, Iranian interference. But the rage burning in people like Muslawi and Hussein has much deeper and older roots. It is the product of centuries of social, political and economic inequality, imposed by repression and prejudice and frequently reinforced by bloodshed. The hatred is not principally about religion. Sunnis and Shi'ites may disagree on some matters of dogma and some details of Islam's early history, but these differences are small--they agree on most of the important tenets of the faith, like the infallibility of the Koran, and they venerate the Prophet Muhammad. Despite the claims by some Arab commentators, there is no evidence that Iraq's Shi'ite extremists are trying to convert Sunnis, or vice versa. For Iraqi fighters on both sides, "their sect is nothing more than a uniform, a convenient way to tell friend from enemy," says Ghanim Hashem Kudhir, who teaches modern Islamic history at Baghdad's Mustansiriya University. "What binds them is not religion but common historical experience: Shi'ites see themselves as the oppressed, and they see Sunnis as the oppressors."  Sunnis and Shi'ites are fighting for a secular prize: political domination. The warring sects, says a U.S. official in Baghdad, "are simply communities ... striving to gain or regain power." Without an understanding of the roots of the rage that drives people like Muslawi and Hussein, any plan--American or Iraqi, military or political--to stabilize Iraq is doomed to failure. And that power struggle in Iraq, whether it draws neighboring countries into a wider sectarian conflict or forces a realignment of alliances, has the potential to radically alter the Middle East.
The war between the two Islamic sects has left the U.S.'s hopes of building a stable Iraq in ruins. A look at the roots of the struggle and whether anything can stop it