The six Guantanamo prisoners charged with participating in the 9/11 mass murders are "poster children for the death penalty," Attorney General Michael Mukasey told students in response to a question after a March 14 speech at the London School of Economics. True.

But Mukasey added a postscript: "In a way, I kind of hope from a personal standpoint — and I can say this because the military commissions will be run by the Department of Defense, not by the Justice Department, although we are participating with them … I kind of hope they don’t get it, because many of them want to be martyrs."

I kind of hope they don’t get it. Coming from the chief law enforcement officer of an administration that avidly supports the death penalty, especially for mass-murdering jihadists, this was a stunning assertion.

It was also a wise one. And I hope that it was not just an inadvertent slip into candor and common sense — a "gaffe," in Washington parlance. I hope that it was a strategically timed move to get the Bush administration to think things through, for once, and to slow down the jihadist-execution train before it gets too far down the track.

(Mukasey can be forgiven for adding an inartful analogy about "the masochist [who] says ‘Hit me’ and the sadist [who] says ‘No.’ ")

Of course, as Mukasey suggested, it’s hard to imagine a more deserving candidate for the death penalty than Khalid Shaikh Mohammed, who has admitted masterminding the 9/11 attacks and is proud of it.

But giving the terrorist murderers what they deserve makes no sense if the result would be to set back our war against jihadism. Aside from satisfying the jihadists’ mad lust for martyrdom, executions would also hurt us badly in the broader war by further inflaming anger at America across Western Europe and the Islamic world.

A federal Appeals Court’s unanimous rejection on June 11 of President Bush’s effort to deny judicial review and due process to a legal alien who has been militarily incarcerated for four years — because Bush says he is a Qaeda agent — was a ringing and welcome defense of our constitutional freedoms.

But I worry that two of the three judges may have gone too far, or exposed a gap in our laws that Congress needs to fill, in their additional, broader holding. It was that Ali Saleh Kahlah al-Marri and other suspected Qaeda terrorists arrested in the United States cannot be detained at all, no matter how dangerous, unless the government brings criminal charges against them within a week of arrest or is unable to deport them.

Whether or not correct as a matter of law, this majority opinion points, in my view, to the need for explicit congressional authorization of prolonged (although not indefinite) detention and aggressive (although not abusive) interrogation of suspected Qaeda agents who cannot be criminally prosecuted. Congress should also require muscular due process safeguards and exacting judicial review, which the Bush administration has furiously opposed, to prevent erroneous detentions of innocent people.

More broadly, the chasm between the views of the president and these two judges on how such cases should be handled illustrates yet again the need for Congress to end its shameful abdication of its duty to rethink the war-on-terrorism’s detention and interrogation policy from the ground up.

The easy issue in the al-Marri case is whether foreigners living legally in this country who are suspected of being Qaeda sleeper agents — such as al-Marri, a Qatari graduate student at Bradley University who lived in Peoria, Ill., with his wife and five children — can be subjected to long-term military detention based solely on the president’s say-so, with no right to due process or judicial review.

A front-page, February 20 federal appeals court decision moved another big "enemy combatant" case down the road toward an eventual Supreme Court decision, probably in June 2008. But the outcome, like the current situation, will be unsatisfactory no matter how the justices rule.

This problem is one that only Congress can solve: how to handle appeals by foreigners who are detained indefinitely as enemy combatants by U.S. forces abroad but who claim to be innocent civilians. Despite two new laws over the past 14 months, Congress has not yet devised a process that is either effective in catching and incarcerating bad guys or fair in the exacting eyes of world opinion.

The justices cannot solve this problem without unseemly gymnastics, because current law presents them with two bad alternatives. The first would be to uphold the sharp restrictions on federal judicial review of appeals by militarily detained terrorism suspects that Congress imposed in the October 2006 Military Commissions Act. That’s what a sharply divided three-judge panel of the U.S. Court of Appeals for the District of Columbia Circuit did on February 20, in Boumediene v. Bush.

But as my December 16 column details, the MCA, even if constitutional, is neither fair to detainees nor credible to world opinion. It is thereby self-defeating, because it makes it harder to get other nations to help us get our hands on bad guys in the first place.

For these reasons the justices may well reverse the D.C. Circuit and strike down the relevant MCA provisions. Such a decision could, if written broadly, give every suspected terrorist captured anywhere in the world a historically unprecedented federal constitutional right to file a habeas corpus petition in federal district court demanding legal representation, release, a ban on interrogation, and/or nicer conditions of confinement. Such an outcome might (or, in these times, might not) satisfy world opinion.