WHEN is the moment you realize your country is on the brink of disintegration? Perhaps it is when you are too scared to remain in your own home. That's the way it felt to Muhammad Ali, a 27-year-old Sunni in Baghdad's mixed Shia-Sunni neighborhood of Doura. in the hours after a terrorist bomb in nearby Samarra destroyed the sacred Askariya mosque -- where revered Shia imams are entombed -- angry Shiites, their faces wrapped in kaffiyehs, roared down Ali's street in opel and Kia passenger cars bristling with AK-47s and rocket-propelled grenades. Minutes later, Ali heard three loud blasts: a nearby Sunni mosque had been hit with RPGs. "We were terrified," says Ali, his voice cracking. "We never had something like this in my neighborhood."

Early the next morning a friend came by Ali's house with a blunt warning: "Get out." A half kilometer away, the friend said, he'd come up on a large field bordering railroad tracks, a place where kids normally kick around a soccer ball. Now it was littered with the victims of Shiite reprisal attacks. "Sometimes people throw their heavy garbage in this place," says Ali (not his real name, which he fears would make him a target if published). "Now they are leaving bodies. it's unbelievable." Braving a harrowing dash through militia checkpoints in a taxi, when AK-47s were waved in his face, Ali brought his mother, two sisters and brother to safety at an uncle's house in a Sunni-dominated area. There they remain, frightened and waiting for what comes next -fearing both the known and the unknowable.

iraq could be on the verge of degenerating from a barely managed quagmire into something worse. US Ambassador Zalmay Khalilzad says the nation seemed as close to civil war as it had ever been. "We're not completely out of danger yet," he said on Saturday. Rising to the crisis, President Bush on that same day telephoned seven key iraqi leaders, including interim

Prime Minister ibrahim Jaafari and Shiite alliance leader Abdul Aziz al-Hakim, as well as two influential Sunni politicians. The president urged them all to continue trying to form a government of national unity. But even Bush, who tends to put the best gloss on things, declared that "the coming days will be intense."

iraq's brief reign of terror was further proof that the nation's 200,000-odd security forces -which witnesses said did little or nothing to stop the violence -- are simply not ready to maintain stability. over the weekend US forces were sent out to patrol Baghdad neighborhoods, helping the iraqis to loosely enforce what one soldier called an "inshallah" (God willing) curfew that prevented large crowds from gathering until afternoon prayers. in the Baghdad neighborhood of Shula, a Newsweek reporter accompanied three Humvees from the 10th Mountain Division as they rolled up and down narrow streets, their antennas hitting low-hanging power lines. overhead, an unmanned aerial drone scouted for crowd gatherings, and when one was spotted, the US troops drove to the area, blasting a message in Arabic over a loudspeaker: "Attention, attention, the iraqi government has a curfew for your safety until 4 p.m. From 4 to 8, you may go to prayer. The president of iraq urges calm. Thank you for your attention." But even with the extra protection, killing was underway. An iraqi soldier who was standing guard in the neighborhood, Thaer Kadar Abbas, said that two people were murdered overnight, and four young men were kidnapped and executed "just 30 minutes ago." "in this neighborhood, that's a normal day," Captain Greg Stone told Newsweek.

The worst spasm of violence came immediately after the Askariya bombing on February 22. Shiite militias attacked more than 20 Sunni mosques, destroying one and inflicting damage on six more, according to US Army Maj. Gen. Rick Lynch, and they murdered several imams. other accounts put the totals higher. Bands of gunmen killed at least 120 people across the country -- including 46 demonstrators, both Shia and Sunni, who had

protested against the Askariya bombing and were pulled out of cars and shot. Even Grand Ayatollah Ali al-Sistani, the preeminent iraqi Shiite leader who is usually a calming presence, issued an angry statement saying that "if government security services can't provide protection, then believers can with God's help." Talks over the formation of a new government, which had lagged since midDecember parliamentary elections, had broken down.

Still, after a day of reprisals, everyone seemed to pull back from the brink. Jaafari imposed a shaky daytime curfew that held during Friday prayers, providing some evidence that the interim central government was not entirely helpless. The prime minister and Hakim also called for unity, as did the powerful radical cleric Moqtada al-Sadr (although his Mahdi Army militia was believed to be responsible for the worst of the reprisal attacks). Jaafari said all damaged mosques, Shiite and Sunni, would be rebuilt with government money. Hakim, probably the most powerful politician in iraq, pointed a finger at the likely culprit in the Askariya bombing, the Jordanian Abu Musab al-Zarqawi, head of al Qaeda in iraq. "This is what al-Zarqawi is working for, that is, to ignite sectarian strife in the country," Hakim said in a statement broadcast by iraqi television stations. "We call for selfrestraint and not to be dragged down by the plots of the enemy."

Why the change in tone? in part because iraqi party leaders who had been cavalierly indulging in sectarian politics suddenly found themselves "staring into the abyss, and they were recoiling," says a US official in Baghdad who would speak only if he were not identified. "You looked into the eyes of these officials, and it looked like they had been scared straight." Those feelings were summed up at a meeting that Khalilzad attended a day after the attack with some 60 of iraq's leaders. The meeting was boycotted by the dominant Sunni alliance, the iraqi Accordance Front. But one Sunni leader who did show up, cleric Ahmed al Samarrai, was almost moved to tears, says the US official, who was there. "His

voice was cracking, and he was half crying when he said as a person from Samarra, the shrine was an iraqi shrine, not a Sunni or Shia shrine."

What US authorities hope is that existential fear will act as a bonding agent, making clear to iraqis just how dangerous foreign jihadists like Zarqawi are -- and how awful civil war would be. After Jaafari tried to extend the daytime curfew into the weekend, imposing a 24-hour vehicle ban in Baghdad and its suburbs, security began to break down again. on Friday night and Saturday, Sunni insurgents seemed to be getting their licks in. Two rockets were fired at a Shiite mosque in Tuz Khurmatu, north of the capital; a car bomb exploded in the Shiite holy city of Karbala, and 13 members of a Shiite family were gunned down.

Even so, weekend violence was not as severe as what occurred in the first hours after the Askariya attack. "iraqi security forces have control over all parts of the country," said a senior Bush administration official, who did not want to be named because of the sensitivity of the subject. She added that, after Bush's phone call, representatives of the Sunni bloc agreed to show up at a meeting of political leaders at Jaafari's residence Saturday and recommit itself to forming a new government.

Some US officials insist that as bad as things are, the nation is still on a more positive path than it was in some previous periods of turmoil, like the siege of Fallujah in April 2004. Secretary of State Condoleezza Rice complained to reporters last week that "every time there is a patch of turbulence, someone writes, 'it's all over, they've had it, they'll never get this done,' and what happens is the iraqis go through a period in which they come back together."

But each round of sectarian violence tears a wider hole in the community fabric, as seen in the breakup of Shia and Sunni neighborhoods like Muhammad Ali's. That in turn makes all-out civil or sectarian war likelier the next time. And ordinary iraqis seem to have less and less faith in the interim

government of Jaafari, already reeling from accusations of running or permitting Shiite death squads. in Baghdad, there were no reports that government security forces ever confronted members of Sadr's Mahdi Army, which is beginning to resemble Hizbullah in fractured Lebanon. This inability or unwillingness to stop the militias (iraq's security forces are dominated by Shiites) was one reason cited by the Sunni bloc for withdrawing from political negotiations.

Yet Khalilzad is fighting to maintain his influence on the country's political direction: both Jaafari and

Hakim blamed him for inciting the violence by threatening to cut off US aid for "sectarian" groups two days before the Askariya mosque bombing. And US officials admit they don't have any good ideas as yet for dismantling the militias or integrating them into the national forces. During Friday prayers, a cleric loyal to Sadr, Aws al Khafaji, announced that his boss had ordered the formation of a security committee to coordinate activities of the Mahdi Army. "our enemies are not only those who hate Shiites," Khafaji said. "But also the occupation that allowed takfiris (extremists) to enter

worrisome."

the holy shrine and demolish it. We want the occupation troops to leave our country. This is our main demand."

ironically, the Shiite militia menace has led Sunni communities once sympathetic to the insurgency to ask for more US military patrols, said one senior US official in Washington who spoke on condition of anonymity. And that could imperil US withdrawal plans, which call for a reduction of US troop levels to below 100,000 by the yearend. "Yes, it is worrisome," the US official said with a sigh. "But almost every issue you could raise is

(c) 2006, Newsweek Inc. All rights reserved. Reprinted by arrangement.