Former White House aide I. Lewis "Scooter" Libby, left, follows his attorney, William Jeffress, Jr., upon their arrival at federal court in Washington today. A judge in Libby's CIA leak case said today he will not delay Libby's prison term. PABLO MARTINEZ MONSIVAIS | Associated Press

U.S. District Judge Reggie B. Walton's decision will send Libby's attorneys rushing to an appeals court to block the sentence and could force President Bush to consider calls from Libby's supporters to pardon the former aide.

No date was set for Libby to report to prison but it's expected to be within six to eight weeks. That will be left up to the U.S. Bureau of Prisons, which will also select a facility.

"Unless the Court of Appeals overturns my ruling, he will have to report," Walton said.

Libby's wife, Harriet Grant, wiped tears away from her eye but Libby was stoic as Walton ruled. Libby and Fitzgerald left court without speaking to reporters.

Libby is the highest ranking government official ordered to prison since the Iran Contra affair.

Libby, the former chief of staff to Vice President Dick Cheney, was convicted in March of lying to investigators and obstructing Special Prosecutor Patrick Fitzgerald's inquiry into the 2003 leak of a CIA operative's identity.

Walton never appeared to waiver from his opinion that a delay was unwarranted. After 12 prominent law professors filed documents supporting Libby's request, the judge waived it off as "not something I would expect from a first-year in law school."

He also said he received several "angry, harassing, mean-spirited" letters and phone calls following his sentencing but said they wouldn't factor into his decision.

Libby argued he had a good chance of persuading an appeals court that, when Attorney General John Ashcroft and other senior Justice Department officials recused themselves from the leak investigation, they gave Fitzgerald unconstitutional and unchecked authority.

Walton was skeptical, saying the alternative was to put someone with White House ties in charge of an investigation into the highest levels of the Bush administration.

"If that's going to be how we have to operate, our system is going to be in serious trouble with the average Joe on the street who thinks the system is unfair already," Walton said.

Libby's newly formed appellate team — Lawrence S. Robbins and Mark Stancil — will seek an emergency order delaying the sentence.

Libby's supporters have called for Bush to wipe away Libby's convictions. The president publicly has sidestepped pardon questions, saying he wants to let the legal case play out.