Not one has faced charges or prosecution.
There is great confusion among legal specialists and military officials about what laws, if any, apply to Americans in this force of at least 48,000.
They operate in a decidedly gray legal area. Unlike soldiers, they are not bound by the Uniform Code of Military Justice. Under a special provision secured by American-occupying forces, they are exempt from prosecution by Iraqis for crimes committed there.
"I understand this is war," said Representative Jan Schakowsky, Democrat of Illinois, whose efforts for greater contractor accountability led to an amendment in next year's Pentagon spending bill. "But that's absolutely no excuse for letting this very large force of armed private employees, dare I say mercenaries, run around without any accountability to anyone."
The security firms insist their employees are governed by internal conduct rules and by use-of-force protocols established by the Coalition Provisional Authority, the US occupation government that ruled Iraq for 14 months after the invasion.
But many soldiers on the ground -- who earn in a year what private guards can earn in one month -- say their private counterparts should answer to a higher authority, just as they do. More than 60 US soldiers in Iraq have been court-martialed on murder-related charges involving Iraqi citizens.
Some military analysts and government officials say the contractors could be tried under the Military Extraterritorial Jurisdiction Act, which covers crimes committed abroad. But that law has not been applied to them.
Security firms earn more than $4 billion in government contracts, but the government doesn't know how many private soldiers it has hired, or where all of them are, according to the Government Accountability Office. And the companies are not required to report violent situations involving their employees.
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