The Bush administration’s embarrassed discussion of the prisoner-torture issue has hit a new snag: a strange Justice Department memo that won’t go away.

The Aug. 1, 2002, memo, written by a former top department lawyer who now is a federal judge, was an effort to protect interrogators against criminal prosecution under a federal law prohibiting torture. So the lawyer, Jay S. Bybee, then assistant attorney general in charge of the Office of Legal Counsel, came up with a highly restrictive definition of torture. He wrote that an interrogator, to be culpable under the statute, must inflict pain like the pain that accompanies “death, organ failure or the permanent impairment of a significant body function.”

That narrow language would permit and excuse threats to harm a prisoner’s family, attaching electric wires to his genitals, threatening him with vicious dogs, leading him around like a dog on a leash, standing him naked for hours, photographing him the nude with female U.S. soldiers laughing at his nakedness, and all the other abuses seen in pictures still being shown all over the world. The White House emphasized that it never adopted the definitions in the memo and never authorized torture.

The memo was addressed to Alberto R. Gonzales, the White House counsel, in response to his question. Mr. Gonzales, at a White House briefing, described as “irrelevant and unnecessary” a part of the memo discussing the president’s authority as commander in chief. The Times reported that senior Justice Department officials said the entire memo would be withdrawn.

The incident raises the question of how such a drastic legal statement could have escaped the notice of Attorney General John Ashcroft, whose department allowed it to be sent, and Mr. Bush. If their silence on the matter suggests they are hoping the matter of prisoner torture will blow over, they will be disappointed, and not because the U.S. media keep reporting on it. Those pictures and the disclosures that government lawyers tried to excuse the torture of prisoners has inflamed the Arab and Moslem world, horrified U.S. allies and confirmed our enemies’ worst suspicions.

What is needed is a full and independent investigation of the entire matter – the treatment of prisoners, the legal justifications for torture and the complete record of how the issue was handled within the government, who knew what was going on, and if they didn’t know, why not?