Hired Gun Fetish By PAUL KRUGMAN

As far as I can tell, America has never fought a war in which mercenaries made up a large part of the armed force. But in Iraq, they are so central to the effort that, as Peter W. Singer of the Brookings Institution points out in a new report, “the private military industry has suffered more losses in Iraq than the rest of the coalition of allied nations combined.”

And, yes, the so-called private security contractors are mercenaries. They’re heavily armed. They carry out military missions, but they’re private employees who don’t answer to military discipline. On the other hand, they don’t seem to be accountable to Iraqi or U.S. law, either. And they behave accordingly.

We may never know what really happened in a crowded Baghdad square two weeks ago. Employees of Blackwater USA claim that they were attacked by gunmen. Iraqi police and witnesses say that the contractors began firing randomly at a car that didn’t get out of their way.

What we do know is that more than 20 civilians were killed, including the couple and child in the car. And the Iraqi version of events is entirely consistent with many other documented incidents involving security contractors.

For example, Mr. Singer reminds us that in 2005 “armed contractors from the Zapata firm were detained by U.S. forces, who claimed they saw the private soldiers indiscriminately firing not only at Iraqi civilians, but also U.S. Marines.” The contractors were not charged. In 2006, employees of Aegis, another security firm, posted a “trophy video” on the Internet that showed them shooting civilians, and employees of Triple Canopy, yet another contractor, were fired after alleging that a supervisor engaged in “joy-ride shooting” of Iraqi civilians.

Yet even among the contractors, Blackwater has the worst reputation. On Christmas Eve 2006, a drunken Blackwater employee reportedly shot and killed a guard of the Iraqi vice president. (The employee was flown out of the country, and has not been charged.) In May 2007, Blackwater employees reportedly shot an employee of Iraq’s Interior Ministry, leading to an armed standoff between the firm and Iraqi police.

Iraqis aren’t the only victims of this behavior. Of the nearly 4,000 American service members who have died in Iraq, scores if not hundreds would surely still be alive if it weren’t for the hatred such incidents engender.

Which raises the question, why are Blackwater and other mercenary outfits still playing such a big role in Iraq?

Don’t tell me that they are irreplaceable. The Iraq war has now gone on for four and a half years — longer than American participation in World War II. There has been plenty of time for the Bush administration to find a way to do without mercenaries, if it wanted to.

And the danger out-of-control military contractors pose to American forces has been obvious at least since March 2004, when four armed Blackwater employees blundered into Fallujah in the middle of a delicate military operation, getting themselves killed and precipitating a crisis that probably ended any chance of an acceptable outcome in Iraq.

Yet Blackwater is still there. In fact, last year the State Department gave Blackwater the lead role in diplomatic security in Iraq.

Mr. Singer argues that reliance on private military contractors has let the administration avoid making hard political choices, such as admitting that it didn’t send enough troops in the first place. Contractors, he writes, “offered the potential backstop of additional forces, but with no one having to lose any political capital.” That’s undoubtedly part of the story.

But it’s also worth noting that the Bush administration has tried to privatize every aspect of the U.S. government it can, using taxpayers’ money to give lucrative contracts to its friends — people like Erik Prince, the owner of Blackwater, who has strong Republican connections. You might think that national security would take precedence over the fetish for privatization — but remember, President Bush tried to keep airport security in private hands, even after 9/11.

So the privatization of war — no matter how badly it works — is just part of the pattern.