A federal appeals court yesterday backed the president's power to indefinitely detain a U.S. citizen captured on U.S. soil without any criminal charges, holding that such authority is vital during wartime to protect the nation from terrorist attacks. The ruling, by the U.S. Court of Appeals for the 4th Circuit, came in the case of Jose Padilla, a former gang member and U.S. citizen arrested in Chicago in 2002 and a month later designated an enemy combatant" by President Bush. Padilla has been held without trial in a U.S. naval brig for more than three years, and his case has ignited a fierce battle over the balance between civil liberties and the government's power to fight terrorism since the Sept. 11, 2001, attacks. A host of civil liberties groups and former attorney general Janet Reno weighed in on Padilla's behalf, calling his detention illegal and arguing that the president does not have unchecked power to lock up U.S. citizens indefinitely. In its ruling yesterday, the three-judge panel overturned a lower court. Avidan Cover, a senior associate at Human Rights First, said the ruling "really flies in the face of our understanding of what rights American citizens are entitled to." Opponents have warned that if not constrained by the courts, Padilla's detention could lead to the military being allowed to hold anyone who, for example, checks out what the government considers the wrong kind of reading materials from the library.