The price tag for the post-Sept. 11 wars in Iraq and Afghanistan is often pegged at about $200 billion. That’s the figure the Department of Defense reports for anti-terrorism efforts through May 2005.

Opponents of the war have zeroed in on the sum, often asking what better purposes the money could have been used for.

A report from the Government Accountability Office, the investigative arm of Congress, released Wednesday calls the figure into question. The Defense Department says it spent $191 billion, but the GAO investigation found inaccuracies and discrepancies that could throw the total off by billions of dollars.

“Neither DOD nor Congress can reliably know how much the war is costing, and details on how appropriated funds are being spent, or have historical data useful in considering future funding needs,” the GAO wrote.

In at least one case, the report said, the reported costs may be overstated. The GAO found that the Army based its assessment on the cost of mobilizing reservists on estimates, which differed substantially from payroll information by $21 billion, or about 30 percent.

Many of the problems identified with the Defense Department’s accounting have been identified for some time, and the GAO reports that actions are under way to fix them.

That the problems are beginning to be addressed is good news. But four years into the U.S. response to the Sept. 11 terror attacks, we shouldn’t be struggling to account for the money that has been spent.

We know that troops have gone without the body armor and vehicles they need; we know that billions of dollars have been spent. But the GAO’s report demonstrates that the military, and the country, doesn’t have a clear picture of where that money has gone. Without proper accounting, it becomes much more difficult for Congress and the American people to judge what the appropriate level of funding for the war effort is.