Former White House aide I. Lewis “Scooter” Libby is headed back to court to try to forestall his 2 1/2-year prison term in the CIA leak case.

Libby, the former chief of staff to Vice President Dick Cheney, planned to ask a federal judge Thursday to put the sentence on hold while he appeals his perjury and obstruction conviction.

It would be a longshot request before a judge who has already said he sees no reason to grant it.

But even if U.S. District Judge Reggie B. Walton were to order Libby to prison at Thursday’s hearing, it is unlikely Libby would be taken away in handcuffs. Rather, it would led to more maneuvering in Libby’s legal fight.

If they lose Thursday, Libby’s lawyers have said they asks an appeals court for an emergency order delaying the sentence. Because one of the issues in the appeal is whether Special Prosecutor Patrick Fitzgerald had the authority to charge Libby, defense lawyers also could ask the Supreme Court to step in.

Then there is the pardon question.

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

If Bush were to decide to issue a pardon, a delay would give him more flexibility to pick a time that makes the most political sense.

Bush’s father pardoned former Defense Secretary Caspar Weinberger and five others in the Iran-Contra arms and money affair on Christmas Eve 1992.

President Clinton pardoned more than 100 people on his way out the White House door, including former Housing and Urban Development Secretary Henry Cisneros and Whitewater scandal figure Susan McDougal.

After a monthlong trial, jurors found in March that Libby lied to investigators about how he learned that Valerie Plame, the wife of an outspoken war critic, worked for the CIA, and whom he told.

Libby maintains his innocence and says any misstatements were the result of a bad memory, not deception.

To win a delay of his sentence, Libby’s lawyers would have to show there was a good chance they could overturn the conviction on appeal.

Attorneys argue that, during trial, they were unfairly prohibited from discussing the classified issues that were weighing on Libby’s mind at the time of the leak and from questioning witnesses that could have helped his case.