President Bush seems likely to lose the first big war-on-terrorism battle that has come before the Supreme Court. He richly deserves to lose, for he has claimed absolute, unaccountable power to lock up more than 600 foreigners as "enemy combatants" in his prison camp at Guantanamo Bay, potentially forever, with no semblance of a fair hearing for those who claim to be innocent civilians.

I base my prediction—which some would dispute—on the justices' questions and comments during the April 20 oral argument in the two consolidated Guantanamo cases, Rasul v. Bush and Al Odah v. U.S. In those cases, the families of 16 Kuwaiti, British, and Australian citizens detained at the naval base claim that their relatives are noncombatant civilians seized by mistake.

It also appears quite possible that the Court will rebuff the president's denial of due process to two U.S. citizens, Jose Padilla and Yaser Esam Hamdi, whom he has also labeled "enemy combatants" and has kept locked up in a South Carolina naval brig for two years without criminal charges. The Court has set the Padilla and Hamdi cases for argument on April 28. It will probably decide all of these cases by late June. Karl Rove might want to do some contingency planning: A succession of Supreme Court spankings for unnecessarily trashing civil liberties would not do his candidate much good.

During the Guantanamo argument, Chief Justice William Rehnquist and Justice Antonin Scalia predictably embraced the administration's view that no court in the world can inquire into the president's dubious claim that all of the more than 600 prisoners at Guantanamo, from 40-some countries, are Qaeda or Taliban fighters. But Justice Stephen Breyer seemed to speak for his three liberal colleagues when he asserted, "It seems rather contrary to an idea of a Constitution with three branches that the executive would be free to do whatever they want—whatever they want—without a check."

Instead, Breyer suggested, courts should open their doors to petitions for habeas corpus on behalf of aliens detained overseas by the U.S., while working out "practical" legal rules to avoid interference with battlefield detentions or other sensitive military operations. (Habeas corpus is the common-law writ that prisoners have been able to use for almost 800 years to challenge the legality of their confinement.) The alternative would be to put Guantanamo, over which the U.S. has exercised complete control under a perpetual lease with Cuba since 1903, completely outside the law.

Bush will lose if the four liberals pick up the vote of either Sandra Day O'Connor or Anthony Kennedy, the two centrist justices. They were harder to read. But O'Connor rejected Solicitor General Theodore Olson's contention that a 1950 precedent, Johnson v. Eisentrager, bars federal courts from hearing habeas corpus petitions by Guantanamo detainees. (Olson, whose wife, Barbara, died in the 9/11 attacks, has reportedly pushed in internal discussions for the Pentagon to show more respect for due process.) Kennedy, while asking tough questions of both sides, also seemed unpersuaded by Olson.

This is not to suggest that the plaintiffs clearly have the better of the legal arguments. Eisentrager and other precedents offer some support for the administration's sweeping claims that federal courts have no power to entertain habeas corpus petitions seeking release of aliens detained outside the U.S., and that such prisoners are unprotected by the Fifth Amendment right not to be "deprived of life, liberty, or property, without due process of law." But O'Connor stressed that Eisentrager, which involved German spies convicted by a military commission and imprisoned by the Allied powers in postwar Germany, could be distinguished from the Guantanamo cases, in which there have been no trials or hearings of any kind.

More generally, when presidents push their powers far beyond the legitimate needs of national security, the justices have sometimes put aside their usual deference to the commander-in-chief and pushed back. Bush has foolishly invited such a judicial response ever since his profoundly unwise decision in January 2002—when the military started flying prisoners from Afghanistan to Guantanamo—to spurn both due process and our nation's treaty commitments.

The U.S. pledged in the 1949 Geneva Conventions to provide detailed protections for prisoners of war and noncombatants. Bush found these protections inapplicable to Qaeda and Taliban fighters because he said the detainees were "unlawful combatants," who wore no uniforms and systematically murdered and abused innocent civilians. This was correct as to Qaeda terrorists and some, but not all, Taliban fighters.

What made Bush's position indefensible was his refusal to provide even an informal military tribunal to hear the claims of many of the detainees that they were neither Qaeda nor Taliban, but rather civilian noncombatants. This was a clear violation of Article V of the Third Geneva Convention, Relative to the Treatment of Prisoners of War. It states that "should any doubt arise" as to the status of captives, "such persons shall enjoy the protection of the present convention until such time as their status has been determined by a competent tribunal." This article was designed to protect both POWs and noncombatants from being mistakenly treated as unlawful combatants. The U.S. military has adopted regulations for Article V tribunals and used them in every war since Vietnam, except for the war in Afghanistan.

Had Bush done the same for Guantanamo detainees, some would properly have been freed and most would have been held as unlawful combatants. Any petitions urging federal courts to overrule the military tribunals would have been denied. The courts—including the Supreme Court, if any cases got that far—would almost certainly have held that the Article V tribunals satisfied both the Geneva Conventions and any Fifth Amendment due process requirements.

But there have been no military tribunals at Guantanamo to which courts can defer. (The military commissions established to try a small number of detainees for alleged war crimes are not yet in business and not authorized to hear claims of noncombatant status.) Instead, Bush and his lawyers have insisted that no Article V hearings are necessary, because there is no doubt that each and every Guantanamo detainee is an unlawful Qaeda or Taliban combatant. "The only thing I know for certain is that these are bad people," Bush said last July 17.

In fact, there is a great deal of doubt about that claim. A "senior American military interrogator [estimated] that as many as 20 percent of the Guantanamo prisoners were sent by mistake," the CBS program 60 Minutes II claimed last September. Dozens of the detainees "have no meaningful connection to Al Qaeda or the Taliban ... according to military sources with direct knowledge of the matter," The Los Angeles Times reported in December 2002. Even Defense Secretary Donald Rumsfeld has acknowledged that "sometimes when you capture a big, large group, there will be someone who just happened to be in there that didn't belong in there." And the Pentagon has released more than 130 of the Guantanamo detainees, including the two Britons whose petitions are before the Court in Rasul.

If Bush was so sure that all of the men and boys (as young as 13) sent to Guantanamo were dangerous, unlawful combatants, why have so many been freed? The evidence suggests that well over 100 were Arab students and charity workers, other noncombatants, and Taliban conscripts with no loyalty to that now-defunct regime. Some were mistakenly seized in the fog of a war in which there were no uniforms. Others were sold by Afghan and Pakistani bounty hunters to U.S. forces dangling millions in rewards.

One might speculate that all of the detainees who would have benefited from Article V tribunals have already been freed. But that seems unlikely. And speculations are no excuse for lawlessness.

The Pentagon detailed in February a painstakingly careful, multilayered screening process that it said it uses now before sending new detainees to Guantanamo. It also sketched plans for annual administrative reviews to release any detainees found not to be dangerous. These are welcome steps, but too little and too late. They came only after the administration felt the hot breath of the justices on the back of its neck. And they could be abandoned if Bush wins the absolute power he seeks.

The administration argues that even deferential judicial oversight would hurt the war against terrorism. I think that it would help. It would show the civilized world—which has been horrified by Bush's lawless treatment of foreign prisoners, to the detriment of the alliance against the jihadist barbarians—that America's judiciary still respects the rule of law, even if the president does not.

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