A former CIA agent whose unmasking led to the conviction of former Vice President Dick Cheney's top aide lost an appeal on Thursday to declassify parts of her memoir.

Valerie Plame Wilson and her publisher Simon & Schuster sued the CIA in 2007 to overturn its efforts to black out the dates she worked for the agency prior to 2002 in her now published memoir Fair Game.

The second circuit federal appeals court ruled on Thursday that the agency had demonstrated good reason for wanting Plame's dates of service to remain classified.

Because Ms. Wilson is obligated by a secrecy agreement with the CIA not to disclose information, the district court correctly ruled, the opinion said.

Plame's identity as an agent was leaked to reporters and appeared in a newspaper column in 2003, shortly after her husband, former Ambassador Joseph Wilson, emerged as an Iraq war critic.

Cheney's chief of staff, Lewis Scooter Libby, was convicted of lying and obstruction of justice in an investigation of the leak. Former President George W. Bush commuted Libby's 2 1/2-year prison sentence.

Plame and Simon & Schuster, a unit of CBS Corp, argued that much of the censored information was already in the public domain. Fair Game was published with the redacted sections blacked out.

Simon & Schuster announced earlier this year they would publish Cheney's memoirs in 2011 in a deal worth $2 million, according to The New York Times.

Iraq George W. Bush