Reports Tuesday by the International Committee of the Red Cross that CIA doctors participated in the "inhuman" torture of terrorism suspects at secret agency prisons underscore the reality that Americans have yet to get a full accounting of the war crimes committed in their name. The Obama administration has pledged to end torture of detainees, and the president's biggest applause line when he spoke in Turkey on Monday came when he reiterated his intention to close the Guantanamo Bay detention facility. But Mr. Obama has stopped short of calling for an official inquiry into the mistreatment of prisoners under the Bush administration. That's not good enough. Finding out exactly what went wrong is the key to making sure it doesn't happen again.

Basically, there are two models for investigating the misdeeds that have cost the United States its moral standing in much of the world, especially in Muslim countries. One is the 9/11 Commission hearings into the intelligence failures preceding the terrorist attacks in New York and Washington. The other is the Senate Watergate hearings of the 1970s that led to the resignation of former President Richard M. Nixon. University of Maryland law professor Michael Greenberger, who directs the school's Center for Health and Homeland Security, says the Watergate model is preferable because Congress did the investigating itself in that case.  "If a case is serious enough to be investigated, it should be investigated by people who have the power to do something about it," Greenberger says.

 An inquiry on the Watergate model would require Congress to employ skilled, experienced investigators with the highest security clearances who could get to the bottom of exactly how many people were tortured, where they were tortured and what methods were used -- without compromising classified information. That's presumably what Sen. Patrick J. Leahy of Vermont, chairman of the Judiciary Committee, had in mind when he called for a full-scale investigation of CIA torture sites. Such an inquiry need not become a partisan witch hunt if handled properly. Opponents argue there's no point in dwelling on the past and that revealing the CIA's interrogation methods will make it harder to get information out of terrorist suspects. But most experts think torture doesn't produce reliable information anyway because people will say anything to make the pain stop; techniques that produce bonding between interrogators and detainees are more likely to result in actionable intelligence. As for dwelling on the past, denial simply is not an option at this point: As the philosopher George Santayana observed, those who don't learn from the past are doomed to repeat it.