A three-judge panel of the 4th U.S. Circuit Court of Appeals ruled that the president has the authority to detain a U.S. citizen closely associated with al Qaida.
A federal judge in South Carolina had ruled in March that the government cannot hold Padilla indefinitely as an "enemy combatant," a designation President Bush gave him in 2002.
The government views Padilla as a militant who planned attacks on the United States, including with a "dirty bomb" radiological device.