The worthy ambitions of the war in Iraq -- and I still believe there were many -- cannot mask the moral pain of the Abu Ghraib scandal. The cruel and humiliating mistreatment of detainees held in an American prison was unworthy and illegal. It violated our plain and public commitment to observe the humane standards of the Geneva Conventions in the Iraqi conflict. It jeopardizes our authority to intern captured combatants. The soldiers who took taunting photographs and videotapes, including the new set of pictures that appeared in this newspaper on Friday, created documents that speak for themselves. You don't need a military lawyer to comprehend that something was foul and wrong.

The Army's 800th Military Police Brigade had a sterling reputation in the 1991 Persian Gulf War. It ran detention camps for 100,000 combatants without apparent incident. Its reputation in the current Iraq war now lies in tatters, redeemed only in part by the actions of Army Spec. Joseph Darby, who showed the sense of honor and right conduct that the military must demand. Darby was given a disc of photographs. He looked at the pictures, was aghast, and turned over the damning evidence to his superiors. The Army's investigation followed, with a hard-hitting report by Maj. Gen. Antonio M. Taguba.

Congress is now deep into further investigations, figuring out how things went so wrong. Secretary of Defense Donald H. Rumsfeld has also appointed an investigative board, with former defense secretaries James R. Schlesinger and Harold Brown, retired Air Force Gen. Charles Horner (head of the air command in the '91 Gulf War) and a no-nonsense former congresswoman, Tillie Fowler (R-Fla.).

But it doesn't take a special board to figure out some lessons. First, a confused chain of command can be disastrous. This holds true for combat operations and prisoner protection alike. The law of armed conflict is built on the presumption that the emotions of war are powerful and, at least for a time, can be disfiguring and distorting. Abu Ghraib prison is near Baghdad and under frequent mortar fire. Close supervision by commanders is essential, to remind people of their legal duties and moral obligations. But the cross-wiring between intelligence commanders and MP commanders at Abu Ghraib and elsewhere in Iraq may have allowed each group to eschew responsibility.

Pre-deployment training, along with the Uniform Code of Military Justice, is also supposed to keep military personnel on the straight and narrow, reinforcing their duty to treat all prisoners humanely (whether the prisoners are criminals or combatants). But the MPs at Abu Ghraib may have accepted inappropriate suggestions from intelligence personnel in the prison to grossly abuse prisoners in flagrant disregard of the Geneva Conventions. Some incidents may constitute offenses under the treaties and statutes on torture. The failures of command, supervision and training must be pursued as high as the facts warrant.

Second, soldiers shouldn't be left guessing about the rules. A poster describing the "rules of engagement" for interrogation was posted in Abu Ghraib by the commander of the 519th Military Intelligence Battalion. This card has confounded Congress and the public. "Rules of engagement" is a term usually reserved for combat itself. The card may have given a sense of license to the Abu Ghraib interrogators and, in turn, to the 800th Brigade MPs, even if its intention was to restrict their actions. The card lists preapproved "approaches" for interrogations under the long-standing Army Field Manual 34-52. But other "techniques" could be requested in writing through the chain of command for specific approval by the commanding general. Among the techniques listed in this second category are "sensory deprivation," with a limit of "72 hrs max" and "stress positions" for "no longer than 45 mins," as well as the "presence of mil working dogs." One only has to see the photograph of snapping dogs in the presence of a cowering and stripped Iraqi man to conclude that this card was not effective in communicating taboos.

The commander of U.S. forces in Iraq, Army Lt. Gen. Ricardo Sanchez, testified to Congress last week that no requests for applying these techniques reached him, and he has now barred any future requests, except for those concerning the isolation of prisoners. But merely posting these options may have led some ground-level interrogators to believe that tougher techniques were acceptable and that they could get away with mixing and matching on their own authority or "delegate" to the MPs.

The White House and the Pentagon must make sure that the war against al Qaeda and terrorism does not muddy the standards for an ordinary war. In public, Bush administration officials have said categorically that the Geneva Conventions apply in Iraq, unlike in Afghanistan, where the application was qualified. But did they make that clear enough to commanders and military intelligence officers in Iraq? It doesn't seem so.

Third, the administration needs to go to Congress, sooner rather than later, to discuss what methods it believes are necessary in fighting al Qaeda and to involve Congress in some of the difficult choices. The classified interrogation policies for Guantanamo Bay, Cuba, and for Afghanistan have not been the subject of any outside advisory board at the Department of Defense -- though Rumsfeld has effectively used advisory panels to take a second look at other issues, such as the procedural rules for military commissions and standards for the use of public data in intelligence investigations. (I served on the group looking at military commissions.)

The Guantanamo interrogation policy designed by Maj. Gen. Geoffrey Miller is said to rely on "positive incentives," and members of Congress who have visited the installation and witnessed interrogations have not publicly expressed any concerns. But it is reasonable for the American public and U.S. allies to worry about something they cannot see, especially after the revelations of Abu Ghraib. Certainly, any replicating of interrogation practices from one theater of combat to another has to be anticipated and headed off. The transfer of personnel should be accompanied by retraining, to avoid inadvertent copycat techniques.

Fourth, it would be a useful precaution to assign a military lawyer (called a judge advocate general, or JAG) to monitor and advise in every significant interrogation center, including places where intelligence agencies and contractors may work in conjunction with military personnel. The standards of the Geneva Conventions apply to all Americans in a theater of combat such as Iraq, and Geneva's principles must govern our behavior. JAG officers have a ground-level sense about easy calls, gray areas and red lines where alarms should sound.

Fifth, the administration must ensure that the International Committee of the Red Cross (ICRC) has effective and timely access to all places of military detention. The ICRC is responsible under the Geneva Conventions for monitoring the condition of all prisoners captured in combat. The United States continues to be the largest financial contributor to this 140-year-old organization based in Geneva, because of the ICRC's crucial and accepted role in protecting all combatants, including our own soldiers when they fall into enemy hands. During the Cold War, the ICRC even helped to repatriate American private citizens accused by the Soviets of spying. Its inspections are discreet, and its criticisms are usually raised in private. It is an extra set of eyes and ears for any combatant commander to help guarantee that humanitarian standards are observed.

The Pentagon must also ensure that there is an effective way of sharing ICRC reports in a timely fashion up the chain of command, even though corrective actions for routine matters are often best addressed locally.

America's leadership, in battle and in peace, depends on retaining the moral high ground. A successful transition in Iraq also depends upon moral legitimacy. We lost too much of that legitimacy in the cellblocks at Abu Ghraib. We can't gain it back without a thorough and open investigation and a rededication to the international treaties we have long endorsed. Ruth Wedgwood is Edward B. Burling professor of international law and diplomacy at Johns Hopkins University's School for Advanced and International Studies.

Waiting in plain sight: Detainees inside at Abu Ghraib last week. The abuses might not have occurred, the author suggests, if U.S. officials and military commanders had required those running the prison to conduct its operations openly.