On April 20, Solicitor General Ted Olson told the Supreme Court that the federal courts could not question the indefinite detention of “enemy combatants” held at Guantánamo Bay because as foreigners outside our borders, the detainees have no constitutional rights and no access to courts. A majority of the Justices seemed concerned that if federal courts have no jurisdiction, Guantánamo would be seen as a “lawless enclave,” as John Gibbons, arguing for the detainees, put it. The Solicitor General, who opened his argument reminding the Court that “the United States is at war,” seemed surprised at the prospect that the Court might actually rule against the government in the “war on terrorism.”

When the government stands up on April 28 to defend its detentions of two US citizens–Yaser Hamdi, allegedly captured in Afghanistan, and José Padilla, arrested at O’Hare Airport–as enemy combatants, it won’t argue that they have no constitutional rights. Citizens are indisputably protected by the Constitution. But if the government’s view prevails, US citizens might as well have no rights, because the President will effectively have unilateral authority to hold them indefinitely without trial on his own say-so.

The Bush Administration initially contended that the courts are barred from hearing the claims even of US citizens held as “enemy combatants.” After the most conservative federal court in the country, the US Court of Appeals for the Fourth Circuit, rejected that view, the Administration rethought its position; it now concedes that the courts may exercise review over the detention of citizen “enemy combatants” (but not foreigners). But the scope of review it argues for is so restricted as to be illusory.

According to the Administration, the courts may at most ask whether, solely on the basis of the government’s submissions, the President had “some evidence” to label a person an enemy combatant. In Hamdi’s and Padilla’s cases, the government has relied entirely on a two-page affidavit from a mid-level Pentagon functionary, Michael Mobbs. Mobbs had no firsthand information and merely relayed the untested assertions of unidentified sources. In the government’s view, the courts may not assess the reliability of Mobbs’s assertions; Hamdi and Padilla have no right to participate in the review or even consult with their lawyers; and their lawyers may not offer any evidence to contradict Mobbs’s contentions.

While the government’s position is so obviously unsatisfactory that even former Administration stalwarts like Viet Dinh have backed away from it, these are not easy cases. Both lower appellate courts, for example, may have gone too far. The Fourth Circuit ruled that because it was undisputed that Hamdi was captured on the battlefield, the courts had no role to play. But nothing in the case can be “undisputed,” as neither the court nor Hamdi’s lawyers were ever permitted to ask Hamdi himself. The Second Circuit’s decision probably went too far in the other direction. It reasoned that the President lacks authority to hold citizens as enemy combatants without express authorization from Congress. Checks and balances are undoubtedly critical, but that view suggests that if a citizen who was an Al Qaeda member were apprehended entering the country with a nuclear bomb, the President could not detain him as a combatant. It has long been accepted, however, that the President, as Commander in Chief, has the authority and indeed obligation to protect the country. Surely in responding to an armed attack he can do so by detaining those fighting for an enemy, citizen or not. That’s what President Roosevelt did when a US citizen entered the country in a German plot to blow up defense facilities. In any event, Congress expressly authorized the use of military force against Al Qaeda, and if it is permissible therefore to kill Al Qaeda combatants, it must also be permissible to detain them.

But here’s the rub: Who’s to say that Hamdi and Padilla are enemy combatants at all? Thus far, we have only the President’s word and Mobbs’s untested affidavits. We shouldn’t take Padilla’s word that he is innocent, but neither should we take the President’s word that he is guilty. A workable solution must acknowledge that the authorization to use military force against Al Qaeda and the Taliban implies the authority to detain their combatants for the duration of the conflict. But unless the President is to be afforded wholly unfettered power, the courts must assure that all detainees–citizens and foreign nationals alike–are given a fair hearing to determine their status. That is what the Geneva Conventions and our own military regulations require; that’s what due process must demand. And that is what the Administration has consistently refused to provide. The power to lock up human beings indefinitely cannot be left to George W. Bush’s unilateral determination that they are “bad guys.”