Several months ago, before Haditha was a household name synonymous with allegations of murder and misbehavior against US troops, Rep. John Murtha made a provocative statement.
"The tremendous pressure and the redeployment over and over again is a big part of this," the Pennsylvania Democrat said of the incident in a May 17 briefing. "And this strain has caused them to crack in situations like this."
The assertion, which set in motion the debate that has followed, won him few friends in the military and was dismissed by critics as the statement of a partisan antiwar monger. But the underlying statement has gone largely unanswered.
Of course, no answer can be absolute. Many seasoned marines are likely to be calmer on their third tour than their first, for instance. But a number of current and former troops suggest that amid the daily calamity of war, everyone has their breaking point, and the seemingly endless nature of this war could, in some cases, cause frustration to boil over into criminal violence.
They are quick not to prejudge fellow soldiers and marines implicated in the five murder investigations that have emerged recently. And they differ on how important a role repeated deployments can play. But the stress of serving multiple tours can have an effect, several say, and should not be dismissed.
"War can make you do terrible things," says Lawrence Provost, who deployed to Afghanistan and Iraq with the Army Reserve. "Multiple tours can be a catalyst for these sorts of things."
The issue is a difficult one for soldiers and marines to discuss. To admit that repeated deployments can wear down their judgment or effectiveness is to admit, in effect, that they are not up to the job that has been given them. This runs counter to a bedrock tenet of the armed services, which is to do whatever job the nation gives them with pride and professionalism.
Moreover, soldiers and marines resent what they see as the self-righteous condemnation of critics who sit thousands of miles from the fight and have little concept of what it means to fight an insurgency.
"I don't think marines resent the attempt to wage an ethical war," says David Danelo, a captain who served in Fallujah with the Marines and has since written "Blood Stripes: The Grunt's View of the War in Iraq." "They resent being lectured about it by folks who have no idea."
So Mr. Danelo and his colleagues come cautiously to the issue of potential war crimes, with sympathy for the accused but also with the conviction that the armed forces must act with honor. In this context, some say the rapid pace of deployment can lead to the sort of behavior that spawns criminal charges.
"I believe that both operational tempo and the stress of a combat environment are contributing factors to the recent spate of murder allegations," says a Marine officer who has served two tours in Iraq and spoke by e-mail on the condition that he would not be named, since he was not cleared to discuss the topic.
To some, the stress of a combat environment where friend and foe blur into uncertainty is by far the more relevant pressure. Laying the blame on repeated deployments "is trying to paint as an absolute something that is one factor among many," says retired Lt. Col. Ralph Peters, an Army officer who has written 21 books. "The immediate stresses are much more important than the repeated deployments."
Indeed, Danelo argues that the multiple deployments breed experience and temperance. "Guys on their third tour will tell you that they're the best marines in counterinsurgency out there," he says. "More tours means they are more accustomed to establishing a mind-set that does not panic."
Others agree, but only in part. "You see countless people go over there and do a great job on their third tour because they really believe in the mission," says Mr. Provost, the Reserve sergeant. "But we have to really monitor our soldiers' mental health."
Not everyone is so gung-ho, he says, and those who aren't might be loath to admit it – either because they feel they are letting down their friends or because they fear being branded weak. "That stigma needs to be taken away, because if you have a GI who can't do [his job], he becomes a liability to his buddies," Provost says.
Those feelings of getting worn down are hardly unusual, say psychiatrists. "Multiple tours is an example of that," says Arthur Blank, former director of the Department of Veterans Affairs counseling services.
"How much it contributes, we're not sure," he adds. "But speaking generally, it is a negative factor."
The Marine officer who has already served two tours in Iraq is fond of telling his troops "that our World War II veterans averaged nearly two years away from family and friends."
But at least then, "those guys knew they were in it for the duration," says Provost. "Here it's out in the open, and we don't know."