Only one thing is clear about the legal resolution of the Haditha case: no one is entirely happy with it.

Supporters of the accused Marines are still angry about the initial version of the story that portrayed the squad as cold-blooded executionersThe fact that none of the Marines involved will serve any time in prison provoked outrage in Iraq and across the world. And it’s done little to clarify the rules of war.

Victor Hansen, an expert in military law and former officer with the Army’s Judge Advocate General corps, said he’s “frustrated like many who are observing it from the outside.”

But he’s also frustrated because the trial didn’t clarify the understanding of the Rules of Engagement — the criteria for using deadly force. They can change from deployment to deployment.

Sometimes it’s okay to “shoot first and ask questions later;” sometimes it’s not. So the question in this case was: Did Staff Sergeant Wuterich use proper procedures to identify his targets before ordering an attack?

“I don’t think there is a sense of clarity in terms of this case you know in terms of what you say positive identification what level of specificity should these Marines have had when they went into the home,” Hansen said.

Gary Myers, who has been practicing military law for 43 years, was involved in the defense of the soldiers charged with crimes from the Vietnam-era My Lai incident and the Iraq War-era Abu Ghraib prisoner abuse scandal. He also defended Lance Corporal Justin Sharratt, whose charges for murder in the Haditha incident were ultimately dropped.

“If anything it’s enhanced ambiguity,” Myers said.

Myers worries that ambiguity can be deadly for servicemen.

“My great fear from these prosecutions is that you have soldiers and Marines in the field who because of fear of prosecution become reluctant to fire their weapons,” he said. “Which compromises their own safety and the safety of their buddies. So we have to be very careful about what we do in circumstances such as this.”

But what about the safety of civilians on the ground when the rules of engagement allow for ambiguity? After the Haditha incident became infamous, the Marine Corps changed their training for counterinsurgency operations, adding cultural sensitivity training, and in some cases encouraging that moment of hesitation that can actually put the lives of Marines at risk.

Sarah Holewinski, the executive director of the Campaign for Innocent Victims in Conflict (CIVIC), said she’s seen the change.

“In Afghanistan there’s a lot of talk now about courageous restraint, which means if you’re going after a particular combatant in a community and he is surrounded by civilians you actually do have an obligation to walk away for furtherance of the mission, instead of going after him,” Holewinski said.

But Holewinski said civilians in Afghanistan and Iraq are much more aware of the Haditha verdict than the efforts at restraint. So while the Haditha incident might have transformed the Marine Corps, the outcome of the trials may mean they get little credit.

Watch Rules of Engagement on PBS. See more from FRONTLINE.