In one version of the story, Sgt. 1st Class James Williams, a 17-year Army veteran, braves the narrow, hostile streets of Mosul, Iraq, in the early weeks of the war, charged with getting food for soldiers back on base.

Spotting a vehicle being driven aggressively, he and his men give chase. They catch up with the white Toyota Land Cruiser and remember their platoon leader's order to find a vehicle to replace the 20-year-old Army Humvees that have broken down and are useless for finding and destroying weapons.

"I don't care what you people have to do," Williams remembers his superior saying, according to court documents filed by his attorney. "Just get me a vehicle."

A crowd of 30 to 40 people is gathering, on doorsteps and rooftops. Williams realizes that there's no escape if things get ugly, and he orders his men out -- with the SUV.

In the prosecutors' version, Williams is an irreverent thug, someone who allowed his men to break rules in Iraq by drinking alcohol and keeping their own private guns, someone who pointed a weapon at an Iraqi civilian while stealing his vehicle.

"You can't win the hearts and minds of the people by taking their cars," said Col. Joseph Anderson, a brigade commander with Williams's 101st Airborne Division when it was in Iraq, according to an account of a military court hearing for Williams in the Clarksville, Tenn., Leaf-Chronicle.

Williams, 37, a married father of two who was born and raised in Virginia's rural Northern Neck, is scheduled to face a court-martial Tuesday on charges of armed robbery and dereliction of duty in connection with the seized SUV. He faces the possibility of 15 years in jail and the loss of his career and military benefits.

The case reveals a bit about the laws -- written and unwritten -- that govern day-to-day military life in Iraq, so-called rules of engagement that are typically classified and alien to civilians. These are rules such as the one -- described by both sides -- allowing Williams's unit to seize cars from civilians as long as they give the owner a receipt.

In this case, there were some power politics at play as well. The owner of the SUV turned out to be one of the most prominent sheiks in Mosul, a Sunni city filled with Saddam's former army officers -- people looking for hard proof that the Americans would make their lives better. So when Sheik Ahmed Watban Al-Faisal found out in April 2003 that the vehicle his son was driving had been stolen, he went to the Americans and was directed to Lt. Gen. David H. Petraeus, then commander of the 101st Airborne, one of the most powerful U.S. military commanders in Iraq.

From Mosul, the sheik said in an interview yesterday that the Humvees aggressively chased his son all the way to their home, where two dozen soldiers got out, forced the man to the ground and did something the Iraqis cannot forget -- put a boot on his head, the ultimate humiliation in Arab culture.

"This thing is so big," he said of the seizure, which is still a topic of conversation in the city. It "still hurts me deeply," he added.

The sheik -- whose brother has U.S. citizenship -- said that although he initially had been elated and optimistic at the Americans' arrival in Iraq, many people now have stories like his son's. Soldiers' behavior has improved, he said, but "it is too late."

The military later gave the sheik's family $30,000 in cash for the damaged vehicle.

"Taking civilian property in wartime is a very sensitive matter that may jeopardize the successful accomplishment of the overall mission," the public affairs office at Fort Campbell, Ky., said in a written response to questions about the case. The 101st Airborne is based at Fort Campbell.

A member of the sheik's extended family has since been named Iraq's new president, and Petraeus has been promoted to oversee the building of an Iraqi army and police force.

The case of the seized SUV has elicited opposing, and fervent, interpretations. Williams and his defenders say he was following orders under a code that was both written and simply understood: Secure whatever equipment was necessary to fight the war. The war was in its second month, and Williams's 326th Engineer Battalion was in Mosul, headquarters of a division of Saddam Hussein's Republican Guard. Two of the platoon's four Humvees had broken down.

A court motion by Williams's attorney includes a copy of words on the wallet-size card given to soldiers there:

"Seize PRIVATE property only if it has a military use (e.g. weapons, ammunition, communication equipment, or transportation) & your commander authorizes the seizure based on military necessity. Give the owner a receipt. Check to see if PUBLICLY owned property can substitute. TAKING WAR TROPHIES IS PROHIBITED."

Although both sides agree that Williams failed to give a receipt -- he claimed fear of the escalating tension -- his attorney and some military experts said that vehicles and other property are often taken during wartime emergencies. Williams, who commented only through his attorney, Bernard Casey, said that he is being made a sacrificial lamb to please a powerful Iraqi and that the SUV was used for normal duty for days until the sheik complained.

"The idea that stealing a sheik's SUV will prevent us from winning the hearts and minds of the Iraqi people while the United States is bombing them is a load of baloney," said David Sheldon, a Washington lawyer who specializes in military law. "This is wartime, and a lot is left up to judgment."

Phil Cave, a Virginia lawyer who represents defendants at courts-martial, noted the case of a group of Ohio reservists who face larceny charges for dismantling military vehicles in Iraq for parts to keep fuel-distribution vehicles running in the march to Baghdad. One of those reservists first received the Bronze Star and then was court-martialed.

"The reaction to this has been all over the board," Cave said. "Some people are being cited as heroes, and some are being court-martialed. None of this was done for profit. It was to keep people in the war."

There is no military-wide standard on seizing property; the rules vary from unit to unit, mission to mission. However, military prosecutors argued at Williams's initial hearing in the spring that his unit's rules had been updated before the SUV incident to forbid taking vehicles. Casey -- a former Army judge advocate general who now practices in San Francisco -- countered that there has been no evidence of such an update.

Army officials say it is irrelevant whether Williams's superior ordered him to do it or whether it met the rules of engagement. "The government's position is that the rules of engagement had nothing to do with this criminal act," Fort Campbell's statement said. "The government does not believe the facts in this case constitute a justified taking of civilian property."

Gary Solis, a former Marine Corps judge who teaches military law at West Point, said he had never heard of any authorization to seize civilian vehicles. "If I were a judge, I wouldn't slow down for this," he said of Williams's case. "It doesn't pass the smell test."

Pvt. Alberto Lozano, who was with Williams when the SUV was seized, pleaded guilty to robbery and making a false statement. He was sentenced to 30 months in jail and given a bad-conduct discharge. Second Lt. Bradley Pavlik, the platoon commander, faces a court-martial next month and is expected to argue that although he told his men to get a vehicle, he did not tell them to take one at gunpoint.

Of the 20,000 members of the 101st deployed for the Iraq war, fewer than 20 have ended up in courts-martial, Fort Campbell officials said.

Williams wears a dour expression these days that brightens only when chat turns to war stories from his service in both Iraq conflicts. His wife and children live in Cameron, N.C., but three siblings and his mother still live in Virginia's Westmoreland County, where he visited last week before heading to Fort Campbell. A hearing is scheduled tomorrow on his attorney's motion to dismiss the case.

Regardless of what happens in court, he believes his career is over, his sister said.

"I think he was searching for something," Alice Winebarger, 48, said, noting that her brother was first drawn to the military by his father's World War II stories. "He found a lot of pride in the Army, found his belonging. . . . But this is the end of it, I'm sure."

She paused to consider a better-case scenario. "If he gets out of this and gets sent back to Iraq or Afghanistan or anywhere where there's conflict, he'll go," she said, "because as far as he's concerned, that's his job."

Special correspondent Naseer Nouri in Baghdad contributed to this report.

Army Sgt. 1st Class James Williams says he was following orders to secure whatever equipment is necessary to fight the war in Iraq.