The OLC provides opinions about what is and is not lawful government behavior. By not quickly quashing talk about prosecutions of the authors of the memos -- or, by inference, higher officials who acted on the basis of those memos -- the president has compromised the OLC's usefulness: If its judgments can be criminalized by the next administration, OLC can no longer be considered a bulwark of the rule of law.

On the other hand, four things are clear. First, torture is illegal. Second, if an enemy used some of the "enhanced interrogation" techniques against any American, most Americans would call that torture. Third, that does not mean that the memos defending the legality of those techniques were indefensible, let alone criminal, because: Fourth, the president might be mistaken in saying that there is no difficult choice because coercive interrogation techniques are ineffective.

A congressional panel, or one akin to the 9/11 commission, should discover what former CIA Director George Tenet meant when he said: "I know that this program has saved lives. I know we've disrupted plots." And what former National Intelligence Director Mike McConnell meant when he said: "We have people walking around in this country that are alive today because this process happened."

House Speaker Nancy Pelosi, who was frequently briefed as a member of the Intelligence Committee, could usefully answer the question: What did you know and when did you know it? She regularly conquered reticence about her disapproval of the Bush administration. Why not about the interrogation methods?

Furthermore, four of the president's 15 Cabinet members are former members of Congress, as are the president, vice president and White House chief of staff. So seven of the administration's 18 most senior figures might usefully answer those questions, and this one: What did you do about what you knew?