Revelations that US troops may have targeted and killed civilians in Iraq last year are focusing a bright light on America's rising awareness of and intolerance for war atrocities.
Such acts have become far less acceptable since World War II. And if it took decades before the shootings of Korean War refugees at No Gun Ri or the atrocities by the rampaging US Army "Tiger Force" in Vietnam were made public, such episodes are much harder to ignore or cover up today.
The result is that allegations that US marines shot and killed 24 civilians in Haditha last November have already spawned two military investigations and heavy media coverage.
"The marines I know are as horrified as anyone at the possibility that the stories coming out of Haditha are true," says political scientist John Allen Williams of Loyola University Chicago, who's also a retired US Naval Reserve captain. "We won't know for sure until the investigation runs its course, which it will. There will be no coverup."
At a Pentagon briefing Wednesday, officials said their initial inquiry shows that the Iraqi civilians were killed in an unprovoked attack, contradicting the troops' initial account that they had been fired upon.
"The forensics painted a different story than what the marines had said," said one official, speaking on condition of anonymity. "Bad things happened that day, and it appears marines lied about it."
Meanwhile, military officials in Iraq this week were quick to acknowledge another incident involving civilian casualties. Two women - cousins racing to a maternity hospital in Samarra because one of them was about to give birth - were killed by US forces when they entered a prohibited area and failed to stop.
One reason Americans learn about atrocities more quickly than in previous wars is the arrival of the digital age. Every GI, it seems, carries a digital camera and cellphone along with his weapon, and he also has access to the Internet and e-mail.
At the same time, the media, having either ignored or been kept from knowing about earlier atrocities, now are more eager to investigate and expose them. Modern means of communication - including reporters with satellite phones embedded with combat troops - allow for nearly immediate publication and widespread broadcast of photos and other evidence.
"There is no question in my mind that things are different," says retired Air Force Col. Sam Gardiner. "Clearly, we see a compression in the time an incident can be hidden from the public."
Another reason has to do with the change in the way the nation defines its military role, according to experts. And this may make the issue of civilian casualties - "collateral damage" - more acute.
In World War II, US forces were avenging aggression, and there was little talk of liberating Japan or Germany. Because Americans saw themselves as victims justified in retaliating (as well as retaliating on behalf of victims abroad), US forces were given more latitude in waging war, says defense analyst Loren Thompson of the Lexington Institute in Arlington, Va.
"Once you begin describing yourself as a liberator rather than an avenger, the standard of behavior is raised considerably," says Dr. Thompson.
Deviations from that higher standard are seen not only as besmirching the reputation of those in uniform but undercutting US goals abroad.
"Allegations such as this, regardless of how they are borne out by the facts, can have an effect on the ability of US forces to continue to operate," Army Brig. Gen. Carter Ham of the military's Joint Staff told the Pentagon briefing this week.
Meanwhile, the armed services are openly struggling with the possibility of collateral (i.e., civilian) casualties more inevitable in fighting a counterinsurgency.
The problem becomes greater with more lethal weaponry and multiple deployments. (The Marine Corps battalion was on its third deployment to Iraq when the killings at Haditha occurred).
"All these things seem to me to point to a failure of humanness - by which I mean the inability to transfer from coping in a daily routine with familiar stresses to a fundamentally unfamiliar environment with different, unfamiliar stresses and remain on an acceptably even keel," says retired Army Col. Dan Smith, a military analyst with the Friends Committee on National Legislation, the Quaker lobby in Washington.
"One tends to revert to the level of society in which safety can be found - Iraqis to the tribe or the mosque, soldiers to the squad or platoon," says Col. Smith. "When one of 'ours' is killed by one of 'theirs,' the death is translated into a personal attack, which in its own way reinforces the natural fear instinct - fight or flight."
Purposely killing civilians, states an Army training manual, is especially likely in guerrilla warfare where the enemy combatants do not wear uniforms and in fact may include women and children.
"The fact is that overstressed human beings with loaded weapons are inherently dangerous," states the training manual, referring to soldiers in such situations. "Murder and other atrocities must be reported."