RICHMOND, Va., Oct. 31 — It seemed like a foregone conclusion that the full United States Court of Appeals for the Fourth Circuit would be receptive to the Bush administration’s contention that it has the authority to detain people it calls enemy combatants. The court’s conservative reputation is well known, and in August it decided to rehear the case in which a three-judge appeals panel rejected aspects of the administration’s position. But, based on the pointed, practical and frequently passionate questioning here on Wednesday in the case of Ali al-Marri, the judges of the Fourth Circuit are divided and troubled,...