A federal appeals court scheduled oral arguments for Dec. 3 on whether terrorism defendant Zacarias Moussaoui (search) can question three Al Qaeda witnesses who might aid his defense.

The government has asked the 4th U.S. Circuit Court of Appeals in Richmond, Va., to reverse a lower court and rule that the prisoners are enemy combatants who are beyond the reach of federal judges and criminal defendants.

The prosecution suffered a severe setback when, after refusing to make the prisoners available, U.S. District Judge Leonie Brinkema (search) barred the government from introducing evidence related to the Sept. 11, 2001, attacks against Moussaoui and from seeking the death penalty.

The dispute has delayed the start of a trial in the only U.S. case arising from the Sept. 11 attacks. If the government is unable to keep Moussaoui from questioning the prisoners, the Bush administration may move the case to military jurisdiction, where rules may favor the government in national security matters.

The appeals court heard oral arguments earlier this year on the enemy combatant issue, but at the time the dispute only involved a single prisoner. The appellate judges dismissed that appeal on technical grounds, but strongly indicated they would revisit the dispute.

In acting Wednesday to schedule the oral arguments, the court did not rule on a government request to conduct some or all the proceedings in secret to protect classified information. In the earlier arguments, the court split the proceedings into public and secret sessions.

Brinkema, in Alexandria, Va., authorized Moussaoui to question the prisoners after concluding the captives may back his contention that he had no role in the Sept. 11 attacks.

Moussaoui, who acknowledges his loyalty to Usama bin Laden (search), is charged as a conspirator with the 19 Sept. 11 hijackers in a plot to commit terrorism against the United States.