“I just can’t see how one can look at this change without believing it’s political,” he said.

The termination language was inserted into the bill by Congressional staff members working for Duncan Hunter, the California Republican who is the chairman of the House Armed Services Committee and who declared on Monday that he plans to run for president in 2008.

Image Mr. Bowens office has inspected and audited taxpayer-financed projects like this prison in Nasiriya, Iraq. Credit... Christoph Bangert/Polaris, for The New York Times

Mr. Holly, who is the House Armed Services spokesman as well as a member of Mr. Hunter’s staff, said that politics played no role and that there had been no direction from the administration or lobbying from the companies whose work in Iraq Mr. Bowen’s office has severely critiqued. Three of the companies that have been a particular focus of Mr. Bowen’s investigations, Halliburton, Parsons and Bechtel, said that they had made no effort to lobby against his office.

The idea, Mr. Holly said, was simply to return to a non-wartime footing in which inspectors general in the State Department, the Pentagon and elsewhere would investigate American programs overseas. The definite termination date was also seen as helpful for planning future oversight efforts from Bush administration agencies, he said.

But in Congress, particularly on the Democratic side of the aisle, there have long been accusations that agencies controlled by the Bush administration are not inclined to unearth their own shortcomings in the first place.

The criticism came to a head in a hearing a year ago, when Representative Dennis J. Kucinich, an Ohio Democrat, induced the Pentagon’s acting inspector general, Thomas Gimble, to concede that he had no agents deployed in Iraq, more than two years after the invasion.

A spokesman for the Pentagon inspector general said Thursday that Mr. Gimble had worked to improve that situation, and currently had seven auditors in Baghdad and others working on Iraq-related issues in the United States and elsewhere. Mr. Gimble was in Iraq on Thursday, the spokesman said.

Mr. Bowen’s office has 55 auditors and inspectors in Iraq and about 300 reports and investigations already to its credit, far outstripping any other oversight agency in the country.