Baghdad, Iraq ? The question obsessing the U.S. military is how to train Iraqis to take over responsibility for their internal security from U.S. troops.

A huge U.S. troop presence in Iraqi cities is abrasive, and is a visible symbol of occupation.

Every day one sees scenes like these: A car bomb exploded at 7:10 a.m. Wednesday a block from my hotel, shattering windows and killing two street sweepers. Hours later, the workers in the Milky Way ice cream bar and the Jadriyah Hairdresser for Men were sweeping up piles of glass and plaster in front of their shops. Life goes on here despite the bombs. A force of seven armored U.S. Humvees and tanks swiveled aimlessly around the road, and a couple of dozen U.S. soldiers fanned out on the street.

The message Iraqis draw from this: U.S. troops can’t — or won’t — prevent the bombs, and their own police can’t protect them. This feeds the popular conspiracy theory that the Americans want chaos so they can stay on and take Iraqi oil.

In reality, the Bush administration would love to draw down U.S. troops but is trapped by previous mistakes. U.S. occupation officials rashly abolished the Iraqi army and police. They didn’t start training the new Iraqi police and military to fight insurgents until last summer. Motivating Iraqis to fight such battles has proved very complex.

“It’s one thing to train forces to fight and die for their country against an external enemy,” one U.S. military official told me. “But it is different when you ask people to fight an internal war.”

Why so? Because that internal war has political dimensions. The majority of Iraqis — Shiite Muslims and Kurds — oppose the insurgency, which they view as a Sunni ploy to regain the power they had under Saddam. But Iraqi security forces can’t afford to reflect that sectarian split.

New Iraqi forces should be loyal to an Iraqi government. But Iraq is a failed state, with a weak interim government, and many Iraqis are more loyal to tribe, ethnic group, or religious sect.

So how to create new Iraqi fighting forces that will fight for something called “Iraq”?

For answers, I went to the headquarters of the special police commando units created since August in the Iraqi Interior Ministry. They now number about 5,000 men. They can be moved to wherever there is trouble, and have fought pitched battles against insurgents in several cities.

In a crowded, noisy, smoky office, brigade commander Maj. Gen. Rashid al-Khelfi explained why they fought well.

These units were formed from ex-special forces fighters under Saddam, who considered themselves professionals above sectarian differences — and all of whom “hated Saddam.” Many officers were involved in a failed plot to overthrow Saddam in 1996 and served years in prison. After Saddam fell, they wanted to return to the military but were rejected because they’d worked for the old regime.

“You have to know that not every former soldier under Saddam is a bad guy,” says Rashid.

When Prime Minister Ayad Allawi took office, these officers were asked to organize commando units. They turned to their old prison fraternity, which included all ethnic and religious groups. Because they knew each other well, they could minimize the risk of infiltration by Saddam loyalists; because they retained their old esprit de corps, and hated Saddam remnants, they were ready to fight for the new Iraq.

It’s not clear how widely these units can be replicated. They are distrusted by Shiite political parties because they once fought for Saddam. There is a limit to the number of former Iraqi special forces officers who are trustworthy.

But it’s clear that experienced officers from the old Iraqi forces bring with them vital skills.

Maj. Gen. Adnan Thabit, the jowly overseer of all the police commando units, is even more blunt. He says the United States made a serious strategic error in abolishing the old army, and that the insurgents are still moving faster than the growth of new security institutions in Iraq. To change the balance, more ex-officers must be brought back and mixed with new volunteers.

“The only solution is to form more and more Iraqi special units with experience who are loyal to the country,” Thabit says. When it comes to the military strategy for fighting insurgents, Thabit sounds right.

— Trudy Rubin is a columnist and editorial-board member for the Philadelphia Inquirer.