'I knew that was wrong." Those are the words of Pfc. Lynndie England, as she pleaded guilty Monday to mistreating Iraqi prisoners in the Abu Ghraib scandal.
A year ago, a photo of her giving the thumbs up next to a pyramid of nude prisoners - along with other disturbing pictures of abuse involving her and some of her colleagues - shocked the nation and the world. The images portrayed not only the harm inflicted on the prisoners, but the damage done to America's credibility as a torchbearer for human rights.
Investigations since that time have been extensive: 10 major Pentagon studies, 20 Senate hearings, and Freedom of Information Act findings by the media and human rights groups. But extensive does not equate with exhaustive. Holes remain, and so do questions.
Thanks to probing by the Pentagon and others, the public knows that Abu Ghraib did not represent a few isolated cases. The abuse has stretched in an arc from the US military prison in Guantánamo Bay, Cuba to Afghanistan. The cases of abuse number in the hundreds and include at least two dozen suspicious deaths.
As for punishment, the military has issued either criminal or administrative charges against 125 soldiers and officers related to 350 cases in Iraq and Afghanistan.
It's a different story with senior military officers, however. A study by the Army inspector general - not yet released but reported last week by the media - has exonerated all senior Army officers in Iraq and elsewhere except the brigadier general in charge of US prison facilities in Iraq.
This report differed from the other Pentagon studies in that it was meant to assign responsibility for the abuse scandal. But in light of earlier probes, its clearing of officers up the chain of command raises questions.
Take the case of Lt. Gen. Ricardo Sanchez, commander of all U.S. forces in Iraq. Two earlier Army investigations said General Sanchez "failed to ensure proper staff oversight" of Abu Ghraib, and lacked authorization to classify detainees as not subject to Geneva Convention protection. A Sept. 14, 2003 order bearing Sanchez's signature allowed interrogation techniques that violate the Geneva Convention, such as using guard dogs to incite fear, but Sanchez denies giving such orders.
A distinction must be made between officers who didn't know what was going on but should have, and those who knew and did nothing. But Sen. John Warner (R) of Virginia is right in announcing that the Armed Services Committee will hold hearings to review "the adequacy" of all of the Pentagon's investigations.
Senator Warner says he wants to get at the issue of commanders "being responsible for all their units do or fail to do" - to quote the conclusion of one of the Army's own reports.
Beyond this, the committee should look at the holes left by the probes. The CIA still hasn't shared its own survey of prisoner abuse with Congress. And the "rendition" of terror suspects to foreign countries which use torture is ripe for investigation, as is the role of senior civilian officials.
Warner's committee should get started as soon as possible. There's much still to do.