Vice President Dick Cheney's chief of staff, I. Lewis 'Scooter' Libby walks from the White House on crutches after being indicted by a special prosecutor

Vice President Dick Cheney has named two people to take up the duties of a former aide, who was indicted in connection with a two-year investigation into who revealed the identity of a covert CIA officer.   Meanwhile, in public comments Monday, the CIA officer's husband said unmasking his wife compromised national security. 

Vice President Dick Cheney named attorney David Addington to be his chief of staff and John Hannah to be his national security adviser. 

Both positions had been filled by Lewis Libby, who resigned Friday after a U.S. federal grand jury indicted him on five counts of obstruction of justice, perjury and making false statements to FBI agents.

Mr. Libby's indictment is connected to a two-year investigation into who unmasked covert CIA officer Valerie Plame Wilson.  Her husband, Ambassador Joseph Wilson, has been an outspoken critic of the war against Iraq and says the Bush White House leaked his wife's identity as part of a campaign to discredit him.

Ambassador Wilson emphasized to reporters the seriousness of the case, saying he believes unveiling his wife's secret identity threatens U.S. national security.

Joseph Wilson

"Valerie went to work every day to try and make sure that weapons of mass destruction would not enter this country and go off in an American city," said Mr. Wilson.  "Weapons of mass destruction kill Americans.  They don't kill Republicans and they don't kill just Democrats, however much one party might want that to be the case.  They kill Americans."

He said his wife still works for the CIA, even though her work as a covert officer is over.  And, although he didn't give details, he added that the incident also has endangered his family's safety.

"There have been threats," he added.  "We've coordinated our security with the appropriate law enforcement authorities.  We've enhanced our security posture and we have changed our phone number so we don't get some of these telephone threats."

At the White House, spokesman Scott McClellan declined to comment on the ongoing legal proceedings against Mr. Libby.

"Our counsel's office has directed us not to discuss this matter while it continues.  And that means me not responding to questions about it from this podium," he said.

He added that he doesn't want to say anything that could affect the opportunity for a fair and impartial trial.

"Under our legal system, there is a presumption of innocence," he added.  "And we need to let that legal process continue.  If people want to try and politicize this process, that's their business."

If convicted, Mr. Libby could face up to 30 years in prison and more than $1 million in fines.  He is scheduled to be formally charged on Thursday.