AMONG THE MANY disturbing aspects of the abuse at Abu Ghraib prison is the involvement of private contractors in conducting interrogations. Contractors are playing a widening role in the military, and never more so than in the war in Iraq. Private-sector workers feed and house U.S. troops, maintain sophisticated weapon systems and provide security for the Coalition Provisional Authority. Their growing involvement, and the consequent blurring of military and private roles, was brought home horrifically in March with the murder and mutilation of four security guards employed by Blackwater USA.

But privatized interrogation is troubling on a whole new level. Testifying before the Senate Armed Services Committee, Lt. Gen. Lance L. Smith said 37 contract interrogators were working for the military in Iraq. The revelation underscores the need for rigorous debate about their proper function in wartime, their position in the chain of command and the laws that govern their activities.

Interrogating prisoners is a sensitive function, one that needs to be conducted under clearly delineated rules by people who are properly trained and supervised and, if necessary, subject to punishment. As the country is learning, uniformed personnel don't always meet those criteria. But private citizens are not appropriate for the job.

Maj. Gen. Antonio M. Taguba, who investigated conditions at Abu Ghraib, testified that guards at the prison viewed the contractors as having "competent authority" to direct their activities. His report found that Steven A. Stefanowicz, a contract interrogator for CACI International Inc., an Arlington-based company, "clearly knew his instructions equated to physical abuse" and concludes that Mr. Stefanowicz and John Israel, a civilian interpreter, "were either directly or indirectly responsible for the abuses." Gen. Taguba recommended that Mr. Stefanowicz be reprimanded, fired and stripped of his security clearance.

While seven soldiers have been charged in connection with the abuses, however, the process appears to be notably slower as it applies to the private contractors, who are not subject to military discipline. The Taguba report has been complete for months, yet there is no indication that any prosecutorial activity was in the works before the abuses became public. It wasn't until late last week that the Justice Department said it had opened a criminal investigation of a civilian contractor.

Congress presciently enacted the Military Extraterritorial Jurisdiction Act in 2000 in an effort to cover such crimes, but the law has scarcely been used and has significant gaps. For one thing, it applies only to U.S. citizens; Gen. Taguba said that two translators involved in abuses were from third countries. It also only applies to contractors working for the military -- not other government agencies. Rep. Martin T. Meehan (D-Mass.) introduced a measure last week to close those loopholes.

Meantime, CACI's contract with the Army is administered by the Interior Department and is so vaguely worded that it gave no indication the company would ultimately be called on to supply interrogators, according to Post reporter Ellen McCarthy; that arrangement is now under review. CACI executives have said they haven't been notified of any charges; when the news of Abu Ghraib abuses broke, the company was reduced to downloading the Taguba report from the Internet. If this is the oversight that's in place for contractors, it's time to reassess whether military privatization has gone too far.