American generals have laid bare the facts: Baghdad is on the brink of chaos, and the specter of all-out civil war looms.

Instead of standing down, as had been hoped this year, the U.S. military is preparing for a major operation to try to take back Baghdad’s streets from Shiite and Sunni extremists. The goal is to stem sectarian violence that Iraqi security forces could not control.

The stakes could not be higher: The fate of the U.S. mission in Iraq is on the line as fighting in Lebanon to the west and the rise of a militant Iran to the east threaten American interests throughout the Middle East.

Without a firm grip on Baghdad, the U.S. and its Iraqi allies cannot control the country. But Baghdad’s diverse population of Sunnis, Shiites, Kurds, Turkomen and Christians makes for a volatile mix as the country’s religious and ethnic groups compete for power in the new Iraq. All the tensions that threaten to tear the country apart play themselves out in Baghdad.

Gen. John Abizaid, the top U.S. commander in the Middle East, bluntly spelled out the situation Thursday before a Senate committee.

"I believe that the sectarian violence is probably as bad as I have seen it, in Baghdad in particular, and that if not stopped, it is possible that Iraq could move toward civil war," Abizaid said.

That was hardly news to the 6.5 million residents of Iraq’s shabby, tumultuous capital. Many Iraqis believe their country has been in a low-intensity civil war since the February bombing of a Shiite shrine in Samarra. That blast triggered a wave of reprisal attacks against Sunnis, accelerating a pattern of tit-for-tat killings, kidnappings and bombings.

Abizaid’s comments marked a stunning departure from the public position taken by U.S. military officials here for months. A bare two months ago, Gen. George W. Casey Jr., the top U.S. general in Iraq, was talking about reducing the U.S. military presence this year as Iraqi units took responsibility for more and more territory.

Two months after the Samarra bombing, Maj. Gen. Rick Lynch said U.S. forces had found no "widespread movement" of Shiites and Sunnis away from mixed areas _ at a time the Iraqi government estimated 90,000 people had fled their homes.

Abizaid’s comments also represent a stark admission that Iraq’s vaunted national unity government of Shiites, Sunnis and Kurds is united in name only.

Sunni politicians have yet to bring Sunni insurgents to the bargaining table. Some key Shiite politicians maintain close links to militias.

Without a political agreement on how to share power and wealth, it is unlikely the Baghdad security operation will be little more than a stopgap measure.

U.S. and Iraqi officials have given few details about the upcoming operation, expected to start within days or a few weeks. The U.S. military said 3,700 soldiers from the 172nd Stryker Brigade were being shifted from northern Iraq to Baghdad. As many as 2,000 additional soldiers eventually may be added to the capital district, officials say.

American troops will move into flashpoint neighborhoods _ often with Iraqi troops _ in hopes of intimidating the gunmen and winning the confidence of residents who don’t trust Iraqi forces to protect them regardless of their sect.

If all goes to plan, the next stage will be to fan out to religiously mixed areas around Baghdad to prevent Sunni and Shiite extremists from infiltrating the capital.

At the same time, Iraqi officials say they plan to retrain the 26 national police battalions _ the Interior Ministry’s paramilitary units _ and weed out those suspected of ties to sectarian militias and criminal gangs.

But to succeed, the plan must overcome the same obstacles that have plagued the U.S. effort in Iraq since the collapse of Saddam Hussein’s regime more than three years ago.

The most serious are a lack of enough troops to secure the country, weaknesses in an Iraqi security force rebuilt from scratch after the U.S. disbanded the Iraqi army in 2003 and rivalries among Iraqi religious and ethnic groups.

To reinforce Baghdad, the military is pulling troops out of areas that had been identified as major infiltration routes for foreign fighters entering Iraq from Syria. And northern cities such as Mosul and Tal Afar _ now relatively quiet _ could flare up again if the U.S. presence is diminished.

Reinforcing Baghdad inevitably means weakening U.S. and Iraqi abilities elsewhere, warns former Pentagon analyst Anthony Cordesman.

The fact that the United States feels it must is a "grim warning of just how serious the situation in Iraq has become," he said.


Robert H. Reid is AP correspondent at large and has reported frequently from Iraq since 2003.

© 2006 The Associated Press