It must have sounded like a splendid idea at the time -- and a difficult time it was. There were these murderous human dirtbags, you see, who went looking for trouble and found it. We and our allies captured some of them and had to find a place to keep them.

We needed to get them far from their native environments, where their presence would be a constant provocation and an ongoing security threat. It would have been easy enough, one has to think, to plunk a suitable stockade in some remote corner of the United States. Bring Alcatraz out of mothballs. Something of that sort -- heck, it's a big country.

But sharp minds in the Bush administration figured that these dirtbags were plugged in. They knew important secrets about al-Qaida, perpetrators of 9/11. Some of them were al-Qaida hotshots themselves, or leaders of the Taliban terrorist support group. Getting them to spill those secrets, promptly, could save American lives. And whether or not they talked, better to keep them locked away where they could do no further harm.

How do you persuade a terrorist to talk? You could say pretty please. Or you could twist him into a stress position, blast him with heat or cold or sound. Strap him down and pour water up his nose.

All that kind of stuff is verboten in regular prisons in this country, civilian or military. Oh, but what if the prison were in Cuba? Then we could really jerk a knot in 'em! And keep 'em there till they rot!

Some of them no doubt deserve just that, or worse. Khalid Sheikh Mohammed may have delusions of grandeur about being the brains behind the 9/11 attacks, but it's crystal clear that he must be kept out of commission.

Even with KSM, however, his guilt ought to be determined through a legal process that satisfies American standards of fairness and openness. We can hope that process eventually transpires.

The trickier issue has involved the many captives whose degree of culpability has not been settled. In fact it may be hotly contested.

And, in fact, the U.S. government has decided that several hundred of the men imprisoned over the past six years at the Guantanamo Bay naval station either weren't really terrorists or Taliban fighters, or else the evidence against them wasn't strong enough to make charges stick.

So back home they went -- provided the home folks would take them. Some ended up back on the battlefield, true enough. Maybe they were bad guys all along, or maybe they had fallen under the influence of their cell mates.

What about the wretched residue? Some are heading for trial before panels of military officers. Plenty of others remain in limbo -- they've been labeled as enemy combatants but haven't been charged, or haven't been classified at all. What rights do they have to challenge their captivity?

That brings us to last week's U.S. Supreme Court ruling that affirmed the detainees' right to argue in federal court that their imprisonment is unlawful and to ask a judge to order their release.

For prisoners on U.S. soil, there is no dispute -- they are entitled to seek the writ of habeas corpus, enshrined in our Constitution as the ultimate safeguard against being thrown behind bars on the mere say-so of a tyrannical executive.

The question of habeas corpus for Guantanamo inmates was hardly as cut and dried. Egged on by the wizards running the "war on terror," Congress agreed to legislation stripping Guantanamo detainees of any right to habeas proceedings.

On the Cuban angle, the five justices in the majority in effect said, if Guantanamo is not part of the United States, it might as well be. And depriving the detainees of a means to challenge imprisonment that could continue for who knows how long is simply incompatible with American standards of justice.

The group that lost the argument pitched a Supreme hissy fit. Justice Antonin Scalia invoked the blood of Americans almost sure to die because his colleagues insisted on coddling the enemy and granting rights that shouldn't exist. What an outrageous leap of speculation.

Give Justice Anthony Kennedy, writing the majority opinion, the last word.

"Security depends upon a sophisticated intelligence apparatus and the ability of our Armed Forces to act and to interdict," Kennedy wrote. "There are further considerations, however. Security subsists, too, in fidelity to freedom's first principles. Chief among these are freedom from arbitrary and unlawful restraint and the personal liberty that is secured by adherence to the separation of powers."

For all we know, solid evidence will show that every remaining Guantanamo detainee belongs in custody as a threat to America. But another threat would be a judgment in the world's eyes that we no longer hold to "freedom's first principles" when our system is put to the test.