On the morning of Nov. 19, 2005, after a roadside bomb killed a young US marine driving a Humvee through Haditha, Iraq, marines in his unit killed as many as 24 civilians.
It's not clear why. The marines say they were fired upon. Iraqi witnesses say the marines went on a rampage. Now, as the marines await possible charges, a key question is: Were they following their rules of combat? These "rules of engagement" are under increasing scrutiny as American and civilian losses mount in Iraq.
The Haditha incident and other alleged atrocities by US troops in Iraq posed "some questions about leadership, about whether the military has done all that it can do to make it clear to troops on the ground what they're entitled to do," says John Sifton, a lawyer with Human Rights Watch, based in New York.
If charges are brought against the marines, the key to their defense will be that they were following the rules of engagement, defense lawyers say. "It's clear that that is the direction one must take," says attorney Gary Myers, if it's proved his client killed a civilian. He declined to identify which marine he represents in the Haditha controversy to protect the young man's reputation.
Whether such a defense can prevail depends both on the facts of what happened in Haditha and on whether those who did the killing acted "reasonably," even if they killed civilians, military law experts say.
"No soldier or marine is going to be tried for an honest mistake," says Gary Solis, a former Marine Corps lawyer who teaches the law of war at Georgetown University in Washington.
But if the marines knowingly gunned down innocent civilians, no rules of engagement would condone such behavior, experts say. Lt. Gen. James Mattis, commander of the 1st Marine Expeditionary Force at Camp Pendleton, Calif., is expected to decide in coming weeks whether to bring charges against any of the marines.
Rules of engagement tell troops when they can apply force. They can vary from war zone to war zone, operation to operation, and even mission to mission. They're usually set by "combatant commanders" – those in charge of an entire region, such as Gen. John Abizaid, head of US forces in the Middle East. But some rules must be approved by the secretary of Defense or even the president.
In conflicts like the one in Iraq, applying the rules can be difficult, especially when troops must make split-second decisions. Sometimes, the rules even allow troops to shoot at civilians, if they can't be distinguished as such and appear to pose a threat.
The rules stem from the Joint Chiefs' Standing Rules of Engagement, which are based on laws of war that bar harming unarmed civilians who can be identified as such, says Lt. Col. John "Jay" Mannle, a Marine Corps lawyer. But firing on a car that contains civilians yet fails to slow or stop for a checkpoint – something US troops have done often in Iraq – is justified if those firing have a "reasonable" belief the car is a threat, he adds.
During the November 2004 battle of Fallujah, marines – including some from the unit under suspicion in Haditha – tossed hand grenades into houses or rooms where they believed insurgents to be. That's the tactic that was used in Haditha, too, according to Staff Sgt. Frank Wuterich, who led the squad accused of the killing.
In court papers filed last summer, Sergeant Wuterich said the squad – made up of about 10 marines – went into the houses after taking fire from them and accidentally killed the civilians while clearing rooms with grenades and rifles. (The papers were part of Wuterich's defamation lawsuit against Rep. John Murtha (D) of Pennsylvania, who said in May that the marines killed those civilians in cold blood.)
Residents of Fallujah, however, had been told to leave the city before US and allied forces went in, according to Mr. Solis of Georgetown. Anyone who didn't was regarded as hostile, and US forces were authorized to fire on them. No such warning had been issued in Haditha.
Iraqi witnesses in Haditha claim the marines went on a rampage after a roadside bomb killed Lance Cpl. Miguel Terrazas. The Iraqis say the marines killed four students when the young men happened upon the scene in a taxi, then massacred civilians in nearby houses, including women and children.
Human Rights Watch has asked the Pentagon for copies of the rules of engagement used in Iraq, and the American Civil Liberties Union has filed Freedom of Information Act requests seeking them, but rules of engagement are often classified. "We don't want to tell the bad guys what we might do," says Lt. Col. Scott Fazekas, a Marine Corps spokesman.
Such rules are usually general, Solis says, and, in any event, "are not tactical instructions on how to proceed in a combat situation."
Troops are instructed on the rules and practice using them during predeployment training. How such training is conducted falls to unit commanders to decide. Before going into combat, troops also are issued unclassified "ROE cards" as a reminder of the key rules.
The cards are next to useless, says Lt. Col. David "Bo" Bolgiano, an Air Force Reserve lawyer and former Baltimore police officer who teaches a course in rules of engagement to members of the military. Troops in combat "are not going to have time to consult them," he says. In any event, problems arise not from the rules "but rather their application," he adds, which makes training in how to respond to potential threats the key.
Generally speaking, "the rules are pretty simple," he says. Troops may respond "with force – to include deadly force – to an imminent threat of death or serious bodily harm."
Although defense lawyers are likely to use rules of engagement as a justification if Haditha charges are brought, the outcome is more likely to turn on the facts surrounding the killings, says retired Army Lt. Col. Geoffrey Corn, who teaches at South Texas College of Law in Houston.
If the civilians were killed by mistake as the marines went after insurgents, he said, the legal question is whether the mistake "was a reasonable one."
"The discipline of a military force in battle is built around the core principle that killing on the battlefield is not just permitted, it's required," Colonel Corn said. "But not all killings are justified."