In September 2002, just before the first anniversary of the September 11 attacks, a group of senior Bush administration officials convened for a secret videoconference to make a difficult decision: what to do with six Americans suspected of conspiring with Al Qaeda. The Yemeni-born men from Lackawanna, N.Y., were accused of training at a camp in Afghanistan, where some had met Osama bin Laden. The president's men were divided. For Dick Cheney and his ally, Donald Rumsfeld, the answer was simple: the accused men should be locked up indefinitely as "enemy combatants," and thrown into a military brig with no right to trial or even to see a lawyer. That's what authorities had done with two other Americans, Yaser Hamdi and Jose Padilla. "They are the enemy, and they're right here in the country," Cheney argued, according to a participant. But others were hesitant to take the extraordinary step of stripping the men of their rights, especially because there was no evidence that they had actually carried out any terrorist acts. Instead, John Ashcroft insisted he could bring a tough criminal case against them for providing "material support" to Al Qaeda.

On that day, at least, the attorney general won the debate, and the Lackawanna Six eventually pleaded guilty. It wasn't the first time, or the last, that top Bush officials would spar over such weighty legal issues. For government lawyers, the detention of foreign fighters at Guantanamo Bay, Cuba, hadn't been a tough legal call. After all, they were soldiers fighting on behalf of a hostile enemy, captured on the battlefield. But the administration hadn't anticipated that U.S. citizens might occasionally turn up in the mix. In the months after 9/11 there were fierce debates--and even shouting matches--inside the White House over the treatment of Americans with suspected Qaeda ties. On one side, Ashcroft, perhaps in part protecting his turf, argued in favor of letting the criminal-justice system work, and warned that the White House had to be mindful of public opinion and a potentially wary Supreme Court. On the other, Cheney and Rumsfeld argued that in time of war there are few limits on what a president can do to protect the country. "There have been some very intense disagreements," says a senior law-enforcement official. "It has been a hard-fought war."

It's far from over. Officials say they eventually settled on "informal" rules to decide whether a detained American should be thrown into the brig or brought to trial. But Hamdi and Padilla have challenged their enemy-combatant status. Next week the Supreme Court will hear their arguments, in what could be the most profound legal issue in the terror war: whether the president can lock up American citizens suspected of terrorist links indefinitely, without charges. This week the court will also hear a case to decide if foreign detainees at Guantanamo have any legal rights.

In a speech earlier this year, White House counsel Alberto Gonzales tried to reassure critics, saying the White House had an "elaborate" and "painstaking" system to identify enemy combatants. But it didn't start out that way. In truth, the enemy combatants policy evolved in fits and starts. In the spring of 2002, U.S. soldiers discovered Hamdi, a Louisiana-born, Saudi-raised U.S. citizen, among the hundreds of ragtag Taliban fighters sent to Guantanamo. They realized they had a problem. The other detainees could be tried before military tribunals. But Bush's order authorizing the tribunals had exempted U.S. citizens--a decision intended to disarm critics. Hamdi was flown to a naval brig in Norfolk, Va., while administration lawyers tried to figure out what to do with him. When a local public defender who read about Hamdi in the newspaper petitioned to meet with him, an assistant U.S. attorney made a novel argument in court: Hamdi was an "unlawful enemy combatant," and had no right to counsel.

Administration lawyers concede that there was a seat-of-the-pants quality to the way events unfolded. "There is a sense in which we were making this up as we went along," says one top government attorney. "You have to remember we were dealing with a completely new paradigm: an open-ended conflict, a stateless enemy and a borderless battlefield."

Before long, administration officials would extend the battlefield to Chicago's O'Hare airport, where agents picked up Jose Padilla on May 8, 2002. The Muslim convert was arrested while returning home from Pakistan, where he had allegedly met with a top Qaeda operative and planned to set off a dirty bomb in the United States. He was named a material witness and appointed a lawyer. But prosecutors soon realized they didn't have enough evidence to charge him with any crime. To avoid releasing him, Bush decreed on June 9 that Padilla, too, was an enemy combatant. He was sent to a military brig in South Carolina. At first, administration officials saw no problems with Padilla's treatment. But as the months wore on, Justice lawyers became increasingly uneasy about holding him indefinitely without counsel. Solicitor General Ted Olson warned that the tough stand would probably be rejected by the courts. Administration lawyers went so far as to predict which Supreme Court justices would ultimately side for and against them. But the White House, backed strongly by Cheney, refused to budge. Instead, NEWSWEEK has learned, officials privately debated whether to name more Americans as enemy combatants--including a truck driver from Ohio and a group of men from Portland, Ore.

Last month, as the Supreme Court arguments approached, the White House backed off slightly and allowed Padilla to speak with his lawyer--but only in the presence of military handlers. Padilla wasn't even allowed to tell his lawyer how he was being treated. The administration hoped the meeting would show the court that it isn't indifferent to the rights of Americans, even those suspected of terrorism. The justices will have to decide if the concession was too little, too late.