Baghdad ? You see them everywhere in the Iraqi capital – careening down city streets in white Toyota pickup trucks with mounted machine guns; manning checkpoints to foil suicide bombers. These are the new Iraqi security forces.

As my driver approached an Iraqi intersection one evening, dozens of Iraqi soldiers in camouflage ran toward our car, guns pointed. We had crossed paths with a convoy escorting Iraqi President Jalal Talabani. The good news is that the Iraqi soldiers were protecting their own (and weren’t so trigger-happy as to shoot us).

The sobering news is that the new Iraqi security forces are far from ready to replace U.S. troops.

The issue of when Iraqi forces can defend their own country becomes more pressing as U.S. political pressure grows for a timeline for troop withdrawals. A report of a secret memo to Prime Minister Tony Blair surfaced this week in the British newspaper the Mail saying that “emerging U.S. plans” call for cutting coalition forces from 160,000 to 66,000 troops by early 2006.

It’s hard to believe that such plans are more than a hypothetical option. The Bush administration rejects any timetable until Iraqi forces can handle the insurgents. The Iraqis aren’t even close.

The consequences of a swift U.S. withdrawal would be grim. “It will lead to disaster,” says Laith Kubba, spokesman for Iraqi Prime Minister Ibrahim al-Jaafari. “There will be a bloodbath.”

I heard that forecast not only from Iraqi Shiites, who fear Saddam Hussein’s Baath Party will make a comeback, but also from Iraqi Sunnis who held power under Saddam. Most of the insurgents are Sunnis. Sunnis worry a swift U.S. exit would free Shiites to take revenge against them. Iraqis also fear a U.S. departure would draw even more radical Arab Islamists into their country.

“We are not thinking about a timetable (for a U.S. exit),” Prime Minister Jaafari told me in an interview inside the heavily protected Green Zone. “When we reach the ability to depend on ourselves for security, then the Americans can leave.”

But it’s very hard to predict when Iraqis will be ready. Then-U.S. occupation czar L. Paul Bremer made a huge mistake when he disbanded the Iraqi army in 2003, rather than let Iraqis revamp the institution. Efforts by the United States to build new Iraqi forces have been bumpy.

Defense Secretary Donald H. Rumsfeld’s claim, early last year, that 200,000 Iraqis were providing security proved bogus. When the Pentagon sent Gen. David Petraeus in June 2004 to retrain Iraqi forces, he had to rebuild the military almost from scratch.

Today, there are more than 100 military and police commando battalions, totaling 169,000 Iraqis. But of the 80 military battalions, only three – at most – are fully capable of planning and carrying out counterinsurgency operations on their own. The number may be smaller.

A sizeable number of battalions can carry out operations with coalition support. But the remaining battalions are far less capable. A tour of Iraqi bases also makes it clear that numbers alone won’t determine how well Iraqis will fight.

Motivation is the key. The Iraqi army needs to know for whom and for what it is fighting. In Iraq, such clarity is hard to find.

The government is ethnically split and includes few representatives of alienated Sunnis. Many soldiers are more loyal to ethnic or religious factions than to an Iraqi nation.

“I believe it is not only possible but imperative that the Iraqis take full ownership of their military and police institutions,” Gen. Petraeus said in an interview. But Iraq’s fragmentation makes it hard for an army to fight effectively, or its officers to lead well.

“It all comes down to skill and will,” I was told by a senior U.S. officer. “Training can develop the skill, but the will must really be inspired by Iraqi leaders.

“In many respects,” the officer continued, “the whole endeavor will increasingly rest on the ability of Iraqi leaders in the security forces and government to foster cooperation among factions. It will rest on their ability to convince as many Iraqis as possible – especially Sunni Arabs – to support the new Iraq and oppose the insurgents.”

I believe this officer is correct.

Until Iraqi leaders can pull together, their security forces won’t jell either. This makes U.S. policy heavily dependent on the uncertain abilities of Iraqis to forge some kind of domestic consensus.

Otherwise, U.S. forces will be stuck in Iraq.