A foreigner living legally in the United States, his lawyers say, is not the same as a soldier captured on a battlefield. Even if the president does have the power, they say, he should be required to support his assertions with evidence.

The government argues that Judge Floyd gave Mr. Marri too full a hearing. It cited the recent Military Commissions Act, which says that the courts have no jurisdiction to hear challenges from any alien “who has been determined by the United States to have been properly detained as an enemy combatant.”

The case will be heard Feb. 1.

The government offered Mr. Marri a sort of consolation prize should the appeals court dismiss his case. It said he could try to persuade a combatant status review tribunal, convened by the Defense Department, that he was not an enemy combatant. That would apparently be the first such proceeding on the mainland; all of the others known to have been conducted were at Guantánamo Bay.

A Different View

In a brief filed in November, eight former Justice Department officials, including Janet Reno, the attorney general in the Clinton administration, said that taking Mr. Marri out of the criminal system as his case approached trial “has given to the appearance of manipulation of the judicial process.” The brief listed several criminal statutes available to prosecute people accused of terrorism along with many successful prosecutions under them.

“The criminal justice system has proven that it can make the cases,” Ms. Reno said in an interview. “For the president to be able to designate someone as an enemy combatant, without process and without regulation, just doesn’t make any sense and isn’t necessary.”

Ms. Blomquist, the Justice Department spokeswoman, said, “While we respect the views of former law enforcement officials, the United States cannot afford to retreat to a pre-September 11 mind-set that treats terrorism solely as a domestic law enforcement problem.”

Mr. Marri shared a fantasy with one of his lawyers not long ago. “I’d love to be taken back to Saudi Arabia and they would beat the” — here, he swore — “out of me for six months,” Mr. Marri said, according to Mr. Savage. “It would be brutal, but it would be finite.”