The massacre at Haditha is bringing forth other allegations of American soldiers killing civilians.  In one case, Ishaqi, US commanders have quickly announced that an investigation into the deaths of civilians has discovered no "inappropriate" action.  The details of the Ishaqi action demonstrate the political futility of badly managed counterinsurgency fighting:

Maj. Gen. William B. Caldwell IV, spokesman for Multi-National
Force-Iraq, issued a statement last night saying that investigators had
found no wrongdoing in the Ishaqi raid and that the ground force
commander "properly followed the rules of engagement as he necessarily
escalated the use of force until the threat was eliminated." Caldwell
said troops captured a Kuwaiti-born al-Qaeda cell leader — Ahmad
Abdallah Muhammad Na’is al-Utaybi — and killed an Iraqi bombmaker and
recruiter during the coordinated raid.

The troops took direct
fire from the building upon their arrival, he said. They responded
first with small arms and then by calling in helicopters and, later,
close air-support, essentially destroying the structure, Caldwell said
in the statement. Troops then entered the building and found the Iraqi
bombmaker’s body, along with three dead "noncombatants" and an
estimated nine "collateral deaths."

 It may be true that "rules of engagement" were followed, and that the "collateral deaths" were not the result of intentional US action.  But, politically, none of that matters.  What will be remembered by Iraqis is that more innocent people were killed by American bullets.  And that memory is reinforced by none other than the Prime Minister of Iraq:

In his comments, Mr. Maliki said violence against civilians had
become a "daily phenomenon" by many troops in the American-led
coalition who "do not respect the Iraqi people."

"They crush
them with their vehicles and kill them just on suspicion," he said.
"This is completely unacceptable."

 It seems to me that the US is in a no-win situation.  With such high-level skepticism about American military action, any time civilians are killed, Iraqis will simply not believe whatever US account is forthcoming.  Why on earth should they accept the word of the US military when it investigates itself?  But, there is no way the US military will fully cooperate with an independent Iraqi inquiry into every alleged misuse of force.  To do that would be to open up the possibility of prosecutions of US military personnel in Iraqi courts, something the American leadership will never permit.  It was precisely to avoid this sort of thing that the US has stayed away from the International Criminal Court.

    Inevitably more innocent civilians will be killed in Iraq.  And it will be impossible for the US, through its own investigations, to assuage Iraqi anger.  Such is the cost of what used to be called, in Vietnam, the "credibility gap," but what modern day Confucians might understand as insincerity plain and simple.