ANBAR PROVINCE, Iraq: As an unembedded freelance journalist in Iraq, I have safely driven through scores of American roadblocks all over this country. I have also spent many hours with American troops as they set up and operate these checkpoints.

At the same time, like other reporters here who don't travel with armies of their own -- and like the millions of Iraqis who either have some money or are brave enough to participate in their country's reconstruction -- I live constantly with the fear of being kidnapped. We see every day the damage done with the millions of dollars that Iraq's Baathist and Wahhabist insurgencies make from that appalling business.

So as investigators try to sort out how U.S. troops could have fired on a car carrying newly freed Italian journalist Giuliana Sgrena, wounding her and killing the man who secured her release, I'm thinking about how checkpoints save lives. We don't know exactly what happened at the checkpoint on the way to the Baghdad airport. But I've seen how checkpoints work, and the American soldiers who man them are anything but trigger-happy. They know the consequences of making a mistake.

If the uproar over the shooting leads the Americans to further tighten rules of engagement, that will increase the danger to our troops and make commanders on the ground more reluctant to perform these dangerous operations. As a result, more foreigners and Iraqis will be running the risk of being kidnapped or blown up by suicide bombs.

Traffic checkpoints are an essential tactic in the disruption of terrorism here in Iraq, since car bombers and kidnappers have to use the roads to conduct their criminal business. Apart from certain fixed locations, such as the entrances to the Green Zone or the Baghdad airport, most checkpoints aren't permanent, and they can be set up almost anywhere, in all sorts of situations. Bridges are popular with American commanders, as they funnel traffic. Long highway straightaways are also good, since they provide visibility for both the civilian drivers and the checkpoint soldiers. Sometimes all the vehicles are searched, and sometimes just a few of them.

Anything that makes it harder to spirit a hostage away to the countryside forces urban kidnappers to keep their victims in busy areas, where the likelihood of discovery is far higher. The restriction of movement provides an important geographical focus for search efforts. Indeed, the first thing that local authorities -- American or Iraqi -- do in a kidnap situation here is set up checkpoints. Many times during kidnapping sagas, I've heard Iraqis say things like, "Well, he's probably still in X, because with all these checkpoints, they would never try to move him." For the terrorists, the higher the likelihood of discovery, the less appealing the kidnapping operation becomes.

The details of Sgrena's release and wounding are still in official dispute, but on the street here there's nearly universal certainty that Nicola Calipari, the Italian government agent who died at the checkpoint, bought her with a large ransom. Some Italian officials have intimated as much, though Prime Minister Silvio Berlusconi told an Italian newspaper that no money changed hands. It's also believed that the Italians ransomed two aid workers last fall. If so, this would mean that the Italian government is giving the terrorists money to conduct more violence even as 2,700 young Italians in uniform are helping rebuild this country.

The word here is that although Calipari had briefed the Americans about his mission, he withheld the details, partly because the Americans disapprove of paying off kidnappers, but more importantly because of the essential factor that foreign media coverage of Iraq usually ignores: the Iraqis. If the Italians paid a ransom, Calipari committed a serious crime in a sovereign state fighting desperately to establish the rule of law and defeat internal terrorism.

Though we may never know exactly what happened, I find it hard to believe that the Army's 3rd Infantry Division just opened fire at a car being driven in a normal, unthreatening manner. The realities of checkpoints in Iraq make random shooting at responsible drivers very unlikely. I'm currently reporting a story on a unit of American soldiers. They're drilled with a stopwatch in the task of setting up a checkpoint -- a "serpentine" of concertina wire, at least three orange cones and, farthest out, a warning sign. These warning barriers are never forgotten, because soldiers are scared of car bombs. The farther out a car has to slow down, the better. You will never see disagreement within a platoon over this basic fact of self-preservation.

Long before the Italian incident, orders had come down that deadly force was to be used only as a last resort -- after the failure of obstacles, then flares or smoke bombs or "star clusters," then warning shots, and finally efforts to take out the oncoming vehicle's engine block. These procedures are real. I have seen our soldiers' reluctance to use force and felt the fear it brings. Car bombs cause 30 percent of military casualties.

The checkpoint procedures, which the military calls "fire discipline" and "escalation of force," are designed to prevent soldiers from killing innocent Iraqis who somehow lack the information or common sense to slow down when they approach. Over the period of Sgrena's incarceration, I stood with American troops at various checkpoints between Fallujah and Ramadi in the Sunni heartland of Iraq's Wild West, an area that receives more than 10 times the national average of attacks on American forces. As I finished writing the previous sentence I heard the announcement over the base radio that two members of the combat team I was with had been killed -- by a suicide bomber driving up to a checkpoint. I didn't see that explosion, but I heard it; I had spent much of the day at another U.S. checkpoint not far away.

"Sitting ducks, that's all we are," a 20-year-old combat medic from Texas said to me as we watched Iraqi vehicles thread past the "Alert" sign and through the orange cones and concertina wire of a checkpoint last week. Later, when I asked the sergeant in charge of the platoon if he was enjoying himself, he responded, "Just hanging around waiting to get blown up." This unit has suffered very high casualties, most from car bombs. If any soldiers in Iraq could be expected to be jumpy and triggerhappy, it is the grunts of central Anbar province. But as I watched them run their checkpoint, both before and after the Sgrena incident, they were thoroughly professional.

Driving around this country with Iraqis, including people with quite a lot to hide, I've encountered scores of American checkpoints. Just about everyone knows what to do: You do a slow U-turn and go the other way, you find a route around, or you drive through slowly and wave at the polite 20-year-old from Nashville. In a very small number of cases, one side makes a mistake and something truly tragic happens.

As a foreigner here, I feel threatened by the possibility that the Italian government may have rewarded the kidnappers. But Iraq is not about us foreigners. It is about Iraqis. And it is Iraqis who suffer most from kidnappings and from the transportation of the artillery shells and antitank mines that become roadside devices and car bombs. Kidnapping Iraqis has become an almost routine business transaction here. Local businessmen fetch sums of up to $250,000, while the child of an ordinary family might go for $5,000 or even $1,000. It happens all the time, all over the country. Iraqi Christians, being more prosperous than most, are especially victimized by this growing crime.

But since the Sgrena shooting, I've already sensed even greater reluctance to set up these dangerous checkpoints. "The soldiers don't like doing this, the NCOs don't like it, even the colonel doesn't like it," a young officer told me the other day. "These checkpoints don't happen as much as they used to."

Last summer, at the height of the kidnappings of foreign journalists here, I used to go to bed every night imagining a cold kiss of steel on the back of my neck: the first touch of the knife I feared would behead me. But not anymore. Great strides have been made in Iraq, and the progress continues every day. For law-abiding Iraqis, for reporters and for the soldiers who risk their lives to disrupt the bombers and hostage-takers, anything that makes life easier and more lucrative for the criminals is very bad news.