By Jerry Markon
Washington Post Staff Writer
Sunday, August 6, 2006

Late last year, one of the nation's leading experts on China stepped to the lectern in an Alexandria federal courtroom and admitted to crimes that stunned the Washington diplomatic community.

Donald W. Keyser pleaded guilty to keeping numerous classified documents in his Fairfax County home and to concealing his relationship with a Taiwanese intelligence agent.

The former high-ranking State Department official, who had advised then-Secretary of State Colin L. Powell on China, was scheduled to be sentenced Feb. 24. He faced up to 13 years in prison.

That sentencing has repeatedly been delayed. Now, prosecutors are asking a federal judge to throw out Keyser's plea, arguing that he has failed to fully cooperate with them as the agreement obligated him to do. Defense attorneys say Keyser has cooperated fully.

It is the latest turn in a case that has always contained elements of mystery. When he was charged in September 2004, the FBI said Keyser had passed documents to Taiwanese agents at a series of covert meetings. But court papers filed with his plea in December did not mention passing documents, and it remains unclear whether the case involved espionage.

Prosecutors are asking a judge to find that Keyser violated the terms of the plea agreement and that they are no longer bound by their agreement not to prosecute him further for his conduct. If the judge agrees, Keyser could face more serious charges. It is unclear whether his existing conviction -- for unlawfully removing classified documents and making false statements -- would stand. Legal experts said it is highly unusual for the government to seek to break a plea agreement.

Even after his plea, Keyser said he spent little time e-mailing the Taiwanese agent, Isabelle Cheng, according to a government filing last month in U.S. District Court in Alexandria. But, prosecutors wrote, "e-mail records demonstrate that the defendant provided extensive information to Cheng that he believed was valuable to her work as an intelligence officer."

The information ranged from Keyser's analysis of developments in China to details of his conversations with then-Chinese President Jiang Zemin, prosecutors said. China and Taiwan are adversaries, and the United States maintains formal diplomatic relations only with China.

Prosecutors also said Keyser minimized his sexual relationship with Cheng, even though FBI agents observed the pair engaging in what appeared to be sexual activity in Keyser's car.

Keyser's attorneys have said that the government misrepresented the extent of Keyser's cooperation. In a recent court filing, they said that before his arrest, Keyser submitted to FBI questioning and "provided them essentially the same information that he told them in his post-plea debriefings.

The government, Keyser's attorneys added, has a "stubborn and erroneous belief that Mr. Keyser was a spy."