CBS News Correspondent Barry Bagnato reports the Bush administration asserted that in war, the constitution gives the president broad powers. An attorney for detainees countered that the United States has created a "lawless enclave" at the military base in Cuba, where more than 600 men from 44 countries are being held without access to American courts.
The prisoners in Guantanamo Bay were mostly picked up in the fighting that toppled the Taliban government in Afghanistan and Pakistan in the months following the Sept. 11 attacks.
Their appeal, the first major challenge arising from the U.S. war on terror to reach the high court, asks a basic legal question: Can foreign-born prisoners picked up overseas and held outside U.S. borders use American courts to try win their freedom?
"The question came down to: can the jailor decide who gets jailed?" said CBS foreign affairs analyst Pamela Falk, "with international law, due process and the indefinite detention of non-citizens, all coming into the courtroom."
Attorney John Gibbons said "it's been plain for 215 years" that people in federal detention may file petitions in U.S. courts.
Chief Justice William H. Rehnquist noted that the detainees are not on American soil, and asked how a judge in Washington is to deal with a case from Cuba.
Gibbons said the men should be treated just as prisoners in America are.
"No other law applies there. Cuban law doesn't apply there," he said.
Without that oversight by U.S. judges, there would be no checks and balances on the president's power at Guantanamo, Justice Stephen Breyer observed later.
"The executive would be free to do whatever they want," Breyer told the Bush administration's lawyer, Solicitor General Theodore Olson.
Not so, Olson replied. The United States routinely asserts temporary or nominal control over foreign territory such as military bases, he noted.
"The United States must have and does exercise relatively complete control. Every argument that's being made here today could be made by the 2 million persons that were in custody at the end of World War II and judges would have to decide the circumstances of their detention, whether it's been adequate military process, what control existed over the territory in which they were being kept," he said.
Justice Antonin Scalia said that if the courts are opened to cases from foreign combatants, battlefield detainees would try to use American courts.
In addition to that jurisdictional issue, the court next week takes up two related cases about the rights of American citizens labeled enemy combatants and held under similar restrictions.
The most important theme in all the cases is the power of the president to conduct a new kind of war as he sees fit.
The Bush administration asserts the right to hold and interrogate the men as long as necessary, without formal charges or the guarantee of a trial or access to a lawyer. The administration also asserts the men are not traditional prisoners of war, who would have guaranteed rights under the Geneva Convention.
The lawsuit before the high court was brought by lawyers who had not met their clients. Since then, a few Guantanamo detainees have been granted access to attorneys.
The lawyers say the men are in a nightmarish legal limbo. Furthermore, they say their clients had nothing to do with Sept. 11 and have never harmed Americans.
"They maintain today, as they have throughout this litigation, that they are innocent of wrongdoing, and the United States has never presented evidence to the contrary," lawyers for British and Australian citizens argued in a court filing.
Five British detainees handed over to London last month were released without charge.
Organizations and individuals as varied as British members of Parliament, retired military officers and former American diplomats support the prisoners.
Arrayed on the other side are former U.S. attorneys general, other former military officers and Medal of Honor winners, and conservative legal scholars and lawyers, including failed Supreme Court nominee Robert Bork, a former federal appeals court judge.
"If the court, for the first time in history, interposes the federal judiciary between our armed forces and enemy belligerents held abroad, the court will effect a dangerous and unprecedented revolution in the separation of powers and undermine the ability of the U.S. military to protect our citizens from attack," the Bork group wrote in a friend-of-the-court filing.
The Bush administration also argues that it is necessary to hold the men for questioning. Tom, an interrogator at the base whosaid some prisoners "provided wealths of information … Keys to the network, how it works, who was involved, how it fundraises, how it recruits, how it travels. Ongoing operations, imminent attacks on a number of occasions."
CBS News legal analyst Andrew Cohen predicts the administration will prevail.
"It's a safe bet that the Court will uphold the lower court rulings and dismiss the cases,"