New York Times

Civilian contractors working for the Pentagon in Afghanistan not only outnumber the uniformed troops, according to a report by a Congressional research group, but also form the highest ratio of contractors to military personnel recorded in any war in the history of the United States.

On a superficial level, the shift means that most of those representing the United States in the war will be wearing the scruffy cargo pants, polo shirts, baseball caps and other casual accouterments favored by overseas contractors rather than the fatigues and flight suits of the military.

More fundamentally, the contractors who are a majority of the force in what has become the most important American enterprise abroad are subject to lines of authority that are less clear-cut than they are for their military colleagues.

What is clear, the report says, is that when contractors for the Pentagon or other agencies are not properly managed — as when civilian interrogators committed abuses at Abu Ghraib in Iraq or members of the security firm Blackwater shot and killed 17 Iraqi citizens in Baghdad — the American effort can be severely undermined.

As of March this year, contractors made up 57 percent of the Pentagon’s force in Afghanistan, and if the figure is averaged over the past two years, it is 65 percent, according to the report by the Congressional Research Service.

The contractors — many of them Afghans — handle a variety of jobs, including cooking for the troops, serving as interpreters and even providing security, the report says.

The report says the reliance on contractors has grown steadily, with just a small percentage of contractors serving the Pentagon in World War I, but then growing to nearly a third of the total force in the Korean War and about half in the Balkans and Iraq. The change, the report says, has gradually forced the American military to adapt to a far less regimented and, in many ways, less accountable force.

The growing dependence on contractors is partly because the military has lost some of its logistics and support capacity, especially since the end of the cold war, according to the report. Some of the contractors have skills in critical areas like languages and digital technologies that the military needs.

The issue of the role of contractors in war has been a subject of renewed debate in Washington in recent weeks with disclosures that the Central Intelligence Agency used the company formerly known as Blackwater to help with a covert program, now canceled, to assassinate leaders of Al Qaeda. Lawmakers have demanded to know why such work was outsourced.

The State Department also uses contractors in Iraq and Afghanistan, although both the department and the C.I.A. have said they want to reduce their dependence on outside workers.

Responding to the Congressional research report, Frederick D. Barton, a senior adviser to the Center for Strategic and International Studies in Washington, said it was highly questionable whether contractors brought the same commitment and willingness to take risks as the men and women of the military or the diplomatic services.

He also questioned whether using contractors was cost effective, saying that no one really knew whether having a force made up mainly of contractors whose salaries were often triple or quadruple those of a corresponding soldier or Marine was cheaper or more expensive for the American taxpayer.

With contractors focused on preserving profits and filing paperwork with government auditors, he said, “you grow the part of government that, probably, the taxpayers appreciate least.”

Congress appropriated at least $106 billion for Pentagon contractors in Iraq and Afghanistan from 2003 through the first half of the 2008 fiscal year, the report says.

The report said the combined forces in Iraq and Afghanistan still had more uniformed military personnel than contractors over all: 242,657 contractors and about 282,000 troops as of March 31