Is anyone ever truly prepared to kill?

One dark night in Iraq in February 1991, a U.S. Army tank unit opened fire on two trucks that barreled unexpectedly into its position along the Euphrates river. One was carrying fuel and burst into flames, and as men scattered from the burning trucks, the American soldiers shot them.

"To this day, I don't know if they were civilians or military - it was over in an instant," says Desert Storm veteran Charles Sheehan-Miles. But it wasn't over for him.

"For the first years after the Gulf War it was tough," says the decorated soldier. He had difficulty sleeping, and when he did, the nightmares came. "I was very angry and got drunk all the time; I considered suicide for awhile."

Like many young Americans sent off to war, he was highly skilled as a soldier but not adequately prepared for the realities of combat, particularly the experience of killing.

Much is rightly made of the dedication and sacrifice of those willing to lay down their lives for their country. But what is rarely spoken of, within the military or American society at large, is what it means to kill - to overcome the ingrained resistance most human beings feel to slaying one of their own kind, and the haunting sense of guilt that may accompany such an action. There is a terrible price to be paid by those who go to war, their families, and their communities, say some experts, by ignoring such realities.

"We never in our military manuals address the fact that they go forward to kill," says Lt. Col. David Grossman, a former Army Ranger. "When the reality hits them, it has a profound effect. We have to put mechanisms in place to help them deal with that.

"Every society has a blind spot, an area into which it has great difficulty looking," Colonel Grossman says. "Today that blind spot is killing."

It may seem strange that a central fact of war for millenniums should become an urgent concern now. But some close to the scene say modified warfare training that makes it easier to kill - and a US cultural response that tends to ignore how killing affects soldiers - have taken an unprecedented emotional and psychological toll. A lengthy conflict in Iraq, they worry, could increase that toll dramatically.

Society has a moral obligation, some argue, to better prepare those sent to war, to provide assistance in combat, and to help in the transition home.

"We have a profound responsibility because we send these people into combat on our behalf, to kill for us," says Shannon French, who teaches ethics at the US Naval Academy in Annapolis, Md.

Postwar tragedy may have been averted, says Mr. Sheehan-Miles, if help had been available to his tank unit. "Within my own tank company, half of the married soldiers were divorced within a year after the Gulf War; one shot another over a girl," he says. "They didn't know how to get help, and the Army essentially did nothing."

Psychological injuries of war can't be tied solely to killing alone - seeing close comrades die and other horrors of war are also factors. But mental-health professionals and chaplains who've worked closely with veterans see killing as a significant contributor, along with other demoralizing elements of combat that soldiers experience or see as "a betrayal of what's right," says Veterans Affairs psychiatrist Jonathan Shay.

The devastating impact of war on soldiers was visible after World Wars I and II and the Korean War as well. But particularly evident today is the ongoing toll of the Vietnam War, whose vets are overrepresented in the homeless and prison populations. One-third are said to suffer from post-traumatic stress disorder (PTSD).

In July, the New England Journal of Medicine reported that 16 percent of veterans of the war in Iraq suffer from depression or PTSD, and that fewer than 40 percent have sought help.

Along with several studies, the efforts of two men are stirring thinking within the US military: Grossman, who wrote "On Killing: the Psychological Costs of Learning to Kill in War and Society," and Dr. Shay, who has worked with vets for 20 years at the VA Outpatient Clinic in Boston. Shay has written two books ("Achilles in Vietnam" and "Odysseus in America") that provide in-depth analyses of how combat can affect individual character and the homecoming to civilian society.

The military has hired both to help improve training and recommend changes to military culture.

The military's responsibility to respond is great, Grossman says, because of the way combat has been transformed since World War II. Interviews by a US Army historian during that war showed that only 15 to 20 percent of infantrymen in the European and Pacific theaters chose to fire at the enemy when they were under fire. Resistance to killing was strong.

Whether because of religious and moral teachings or what he terms "a powerful, innate human resistance toward killing one's own species," soldiers' apparent willingness to die rather than kill stunned military officials.

To overcome that resistance, the military revamped its training to program soldiers, through psychological conditioning, to make shooting reflexive. The techniques were applied with "tremendous success," Grossman says, raising the firing rate to 55 percent in the Korean conflict and 95 percent in Vietnam. But little thought, he adds, went to the aftereffects of overriding the soldiers' natural inclinations.

Shay also flags concerns about combat leadership, citing instances when soldiers have been treated unfairly, lacked necessary equipment, been asked to do things they considered wrong, or seen questionable behavior rewarded. These are all experiences he includes under the heading of "the betrayal of what is right." People don't have to be injured by their wartime experience, he adds, but that requires "assuring them cohesion in their units; expert and ethical leadership; and highly realistic training for what they have to do."

The first responsibility of leadership and the public, many say, is not to put the country's sons and daughters at risk unless going to war is essential.

If it is, then they need help sorting through the issues. Rabbi Arnold Resnicoff, a retired Navy chaplain, calls for "spiritual force protection."

"We have a responsibility to understand the dangers war poses to the humanity of our people and do all we can to protect them, to develop 'moral muscle,' " he says.

In "The Code of the Warrior," his course at the Naval Academy, Dr. French focuses on moral distinctions - the historical legacy of the warrior and rules of war, and how to be alert to crossing the boundaries, as occurred at Abu Ghraib prison.

"It has been very well documented that there is a close connection between severe combat stress and the sense of having crossed moral lines," she says.

While the military academies offer officers some ethical training, the rank and file learn mostly from their commanders. Recent training Grossman has provided to Marine battalions heading to Iraq included distinguishing between killing and murder.

"Many have 'Thou shalt not kill' in the back of their minds, and think they've broken a profoundly moral law," he says. Grossman helps them see that the Judeo-Christian ethos generally accepts the idea that killing can be justified at times, and he emphasizes the importance of close adherence to the rules of engagement.

But there are gray areas, particularly in urban conflict, where it is not always clear whether to shoot, says Paul Rieckhoff of the Army National Guard, who led a platoon through combat patrols, raids, and ambushes in Baghdad until February of this year.

During one operation, "a female truck driver dropped us off and was guarding the truck when a kid about 10 years old came around the corner and started shooting at her," he says. "What does she do - shoot him or get shot?"

Vital to the health of soldiers is what happens after each combat experience. It's essential to have "after-action reviews," many say, in which units sort through experiences that were disturbing to them. These may include killing, or seeing their comrades or innocent civilians killed. "The worst thing is to not think about it. You can't not think about something for a lifetime," Grossman says.

At the end of the 1989 US invasion of Panama, Army chaplain R. Ryder Stevens, now retired, and another chaplain sought out soldiers individually. "One guy talked, but kept his M-16 between us and kept taking it apart, cleaning it, and putting it together again," says Colonel Stevens. "Finally he blurted out, 'I murdered a woman and her baby the other day and I'm going to burn in hell!' " He had followed the rules of engagement and shot at a car that didn't stop fully at a checkpoint. After he was assured that God's love was big enough to forgive him, "he fell into my arms crying," Stevens recounts.

In Iraq, there may be one chaplain for every 1,500 soldiers, Rieckhoff says. Those who need help must be encouraged to seek it. But the system is failing, many insist. Seeking help carries a stigma, and procedures for getting help lack privacy.

The case of Sgt. Georg-Andreas Pogany - cited by Sheehan-Miles in his book - is a vivid example of what can go wrong.

Sergeant Pogany experienced panic attacks while serving with the Special Forces in Iraq, and sought medical help. But he was urged to reconsider his request for the sake of his career. Later he faced a court-martial for "cowardice" - the first such case since Vietnam. Only in July 2004, nine months after he was made a public example, was it determined the attacks were probably caused by an antimalarial drug, and all charges were then dropped. [Editor's note: The original version of this story failed to mention that all charges were dropped against Sgt. Georg-Andreas Pogany when it was determined that his panic attacks in Iraq were probably due to an antimalarial drug he had been given.]

"That kind of thing sends shock waves throughout the military community," says Sheehan-Miles, who didn't seek help himself for fear of ending his career. He got back on track only when he began focusing on helping other veterans. Now executive director of Veterans for Common Sense, he asks, "How do you take away the stigma of asking for help?"

Everyone coming home from a war zone should be required to have two or three counseling sessions, Sheehan-Miles proposes. "A lot of people think they don't need it who really do, and it ends up coming out in their lives later on," he says.

The Marine Corps' Warrior Transition Program - a pilot effort run by the chaplain corps of the Marines - is required for everyone returning from Iraq and Afghanistan. During transit home, marines discuss their most positive and negative experiences, and find succor in sharing with others.

Soldiers who may have killed in the line of duty are included in the program, although there is no specific focus on that particular experience.

Rieckhoff, who just formed Operation Truth (www.optruth.org) to enable Iraq vets to explain their experiences to folks back home, says America "isn't ready for the guys to come back the way they are going to come back." Thousands are going to need help and "all you get at the end of the war is a 'a don't-beat-your-wife briefing,' as we call it." The VA needs more funding, he adds, and "the whole nation needs to commit to this."

Shay's ideal for returning soldiers would be peer counseling from volunteer vets, who he says can reach those in need better than can mental-health professionals. This is now happening on a limited basis through VA Readjustment Centers run by vets.

Many say Americans must learn to be honest about the nature of combat. In a culture saturated with media violence, killing has become almost trivialized. Many veterans have the wrenching experience of being asked, "How many people did you kill?"

"They should not be treated as some sort of figure from a video game," says French.

Throughout history, cultures have had various means to purge warriors of their combat experience and help them readjust to civilian life. "Many had purification rites the whole community took part in," Shay says. In ancient Greece, drama provided a cathartic experience for the veterans and the community. Some African societies today have cleansing ceremonies that reintegrate fighters into community life.

He would like to see some interdenominational, nonpartisan civil or religious rite in the US that goes beyond parades and welcome-home ceremonies.

"People coming back from having killed aren't necessarily injured, but need to purify themselves," he says. "And we sent them and need to be purified, too."