The justices are weighing the cases of two U.S. citizens: Yaser Hamdi, a Louisiana-born man of Saudi descent who was captured during fighting in Afghanistan in 2001; and Jose Padilla, a former Chicago gang member arrested in May 2002 on suspicion of plotting with the al-Qaida terror network to set off a radioactive "dirty bomb" in the United States.
The two have been declared enemy combatants and confined in near isolation in a Navy brig in South Carolina. They have each been held without any of the usual protections of the U.S. legal system and were only recently allowed by the military to meet with lawyers and made aware that their cases had reached the nation's top court.
The Supreme Court heard the highly anticipated cases back-to-back, one week after hearing arguments in a third case that asks whether foreign detainees held in a U.S. military base in Guantanamo Bay, Cuba should have the right to challenge their detentions in the American court system.
All three cases present critical legal tests of the limits of presidential power in the wake of the Sept. 11, 2001 terrorist attacks on New York, Washington and Pennsylvania.
Hamdi, who was raised in Saudi Arabia, was captured in Afghanistan in the weeks after the Sept. 11 attacks. The government alleges that he was fighting with Taliban forces, making him a classic battlefield detainee.
"We could have people locked up all over the country tomorrow, with no opportunity to be heard. ... Congress didn't intend for widespread, indefinite detentions," Frank Dunham, the attorney for Hamdi, told Justice Sandra O'Connor on Wednesday, responding to the justice's question about whether the president was granted detention power when Congress passed a resolution authorizing the use of military force shortly after Sept. 11.
"Nowhere does the [statute] have 'detention' in it," Dunham said.
But Deputy Solicitor General Paul Clement, representing the Bush administration, argued that a president as commander in chief has wide latitude under constitutional law to detain suspected terrorists as "enemy combatants" if they pose a national security risk.
"It has been well-established, and long established, that the government has the authority to hold unlawful enemy combatants ... in order to prevent them from returning to the field of battle," he said.
Padilla was arrested two years ago in Chicago's O'Hare International Airport on a flight from Pakistan.
He initially was held as a "material witness" for a federal grand jury investigating the Sept. 11 attacks. But in June 2002, the president invoked his power as commander in chief and declared Padilla an enemy combatant.
A federal appeals court ruled in December 2003 that the U.S. government does not have the authority to detain Padilla as an enemy combatant, ordering the Department of Defense to release him within 30 days. The ruling was later appealed.
"Congress was acting in immediate response to attacks carried out within the nation's borders" when it voted to endorse broad White House authority to go after terrorists, administration lawyers argued in a court filing.
Lawyers for Padilla argued Congress did not authorize such detentions and the White House had overreached its authority.
"If the government's position were accepted, it would mean that for the foreseeable future, any citizen, anywhere, at any time, would be subject to indefinite military detention on the unilateral order of the president," their filing said.
High court rulings in the cases are expected by the end of June.