The United States’ use of mercenary contractors like Blackwater in Iraq has led to unnecessary violence against civilians, inflamed Iraqi sentiment towards the United States and jeopardized military strategies to defeat the insurgency, a new report concludes. "The U.S. government needs to go back to the drawing board and re-evaluate its use of private military contractors," finds the Brookings Institution’s Peter Singer, who authored the report. In particular, he writes, using armed soldiers-for-hire to escort U.S. officials through Iraq, as they now do, "has created both huge vulnerabilities and negative consequences for the overall mission." Singer says his report is based on talking with hundreds of subjects, "from private military firm employees to active and retired soldiers." Click Here to Register to Receive Blotter Alerts. The academic has studied private military contractors for over a decade, and is considered one of the foremost policy experts on the topic. His study was first reported on by TPMmuckraker.com. Military contractors are "one of the most visible and hated aspects of the American presence in Iraq," Singer writes in his paper. While most are "highly talented ex-soldiers," their role — as a buffer between U.S. officials and the Iraqi populace — makes their harshness the public face of the United States in Iraq. "In an effort to keep potential threats away, contractors drive convoys up the wrong side of the road, ram civilian vehicles, toss smoke bombs, and fire weaponry as warnings, all as standard practices," Singer writes. "While understandable" as security measures, "it undermines the broader operation." Blackwater, the private military contractor whom the government of Iraq wants to ban after a recent incident in which Iraqi civilians were killed, "has earned a special reputation among Iraqis," according to Singer, who says the company has been implicated in at least seven incidents of civilian harm. The New York Times reported this morning that internal State Department records show Blackwater personnel have been involved in "dozens of episodes" in which they resorted to force, at a rate twice that of other private military contractors. The company has won more than $1 billion in work with the U.S. government since 2002, mostly with the State Department. "I think that most Iraqis understand that the United States — whether it’s our military forces, our diplomats or otherwise — are there to support them in achieving their ambitions of achieving a secure, peaceful and stable country," State Department deputy spokesman Tom Casey said in response to the report’s findings. The firm did not immediately respond to a request for comment. This post has been updated. Click Here for Full Blotter Coverage.