June 19 (Bloomberg) -- Lewis ``Scooter'' Libby, a former aide to Vice President Dick Cheney, asked a U.S. appeals court to let him stay out of prison while appealing his conviction for obstructing a CIA leak investigation.

Libby, 56, was ordered to prison by U.S. District Judge Reggie Walton on June 14. The judge in Washington said the legal issues Libby plans to raise in his appeal, such as the legality of Patrick Fitzgerald's appointment as special prosecutor in the case, don't warrant allowing him to remain free.

``The constitutionality of Fitzgerald's appointment is a close question'' with unclear legal precedent that should be decided by an appeals court, Ted Wells and other lawyers for Libby said in court papers fled today. Libby ``should be granted release'' until that question is decided, they said.

Libby was sentenced to 2 1/2 years in prison on June 5 following his conviction in March of lying to investigators probing the 2003 leak of Central Intelligence Agency official Valerie Plame's identity. He was convicted of obstructing justice, perjury and making false statements. He resigned as Cheney's chief of staff upon being indicted in 2005.

Wells, of Paul Weiss Rifkind in New York, argued in the court filing that Libby has a substantial chance of having his conviction overturned on appeal.

Special Prosecutor

Fitzgerald was appointed by President George W. Bush and confirmed by the Senate in 2001 to serve as U.S. attorney in Chicago. In December 2003, then-Deputy Attorney General James Comey named him as the special prosecutor to investigate the leak of Plame's identity. Libby's lawyers argued today that Fitzgerald should also have faced Senate confirmation for the latter job.

Fitzgerald, in a June 12 court filing, said Libby's arguments regarding the appointment ``simply cannot withstand scrutiny.'' Walton previously ruled that the ``appointment by the acting attorney general was consistent with the appointments clause'' of the Constitution, the prosecutor said.

Libby's lawyers said other ``close questions'' to be decided on appeal were Walton's decisions to exclude some witness testimony and expert testimony on faulty memories. His lawyers argued during the trial that national security matters kept him too preoccupied to remember details about the leak.

``The district court's rulings worked an unconstitutional burden on Libby's Fifth Amendment rights and left the evidentiary playing field substantially uneven,'' his lawyers wrote.

Joseph Wilson

Randall Samborn, a spokesman for Fitzgerald, declined to comment on the filing by Libby's lawyers.

After almost a two-month trial, Libby was convicted of lying to FBI agents and a grand jury probing whether the Bush administration deliberately leaked Plame's identity to retaliate against her husband, Joseph Wilson. He had accused the government of twisting intelligence to justify the 2003 invasion of Iraq.

Plame's status as a CIA official was disclosed in a July 14, 2003, article by syndicated columnist Robert Novak, eight days after Wilson's column criticizing the Bush administration appeared in the New York Times.

Fitzgerald argued at trial that Libby lied about his knowledge of the leak to protect his job. It's a federal crime to knowingly reveal the identity of a covert CIA agent, and the White House had announced that anyone who leaked Plame's identity would be fired.

Novak testified that Plame's identity was provided to him by then-Deputy Secretary of State Richard Armitage and confirmed by White House political adviser Karl Rove. No one was charged with a crime or fired for the leak.

Libby didn't testify at the trial, nor did Cheney, who had been identified as a possible defense witness.

Libby's supporters have called on Bush to pardon him. White House spokesman Tony Fratto said on June 14 that Bush would ``continue not to intervene in the judicial process.''

The trial court case is U.S. v. Libby, 05cr394, U.S. District Court for the District of Columbia (Washington).

To contact the reporter on this story: Cary O'Reilly at caryoreilly@bloomberg.net.

Last Updated: June 19, 2007 17:01 EDT