At a nearly-three-hour court hearing, Cheney's lawyer said Plame was making "fanciful claims" in what amounted to "a fishing expedition."
Plame says her constitutional rights were violated by Cheney and his now-convicted former chief of staff, I. Lewis "Scooter" Libby, as well as White House political adviser Rove and former State Department official Richard Armitage.
Her suit is "principally based on a desire for publicity and book deals," said Michael Waldman, who represents Armitage.
The case is "about egregious conduct by defendants that ruined a woman's career," countered Plame's lawyer, Erwin Chemerinsky.
Several administration officials, including Armitage, Rove and Libby, disclosed Plame's identity to reporters in 2003. That disclosure came after Plame's husband, Joseph Wilson, accused the administration of twisting prewar intelligence on Iraq.
Evidence at Libby's trial showed that Cheney told Libby about the CIA employment of Wilson's wife more than a month before she was outed.
U.S. District Judge John Bates questioned both sides closely.
"Why would these government officials have any kind of protection for these disclosures" about Plame's classified CIA status? the judge asked.
Rove's lawyer, Robert Luskin, arguing on behalf of all the defendants, said there is no allegation that any of them knowingly disclosed classified information.
The Justice Department has asked Bates to drop an invasion of privacy count in the suit because government officials cannot be sued personally for such claims when acting in their official capacity.
"There is nothing these officials could have said that could go beyond the scope of their employment?" asked Bates.
Not in the context of the Plame affair, replied Justice Department lawyer Jeffrey Bucholtz. What the suit alleges amounts to a government policy dispute in which the defendants tried to discredit Plame's husband, Bucholtz said.
Plame's lawyer responded that the scope of employment ends where the outing of Plame's CIA identity begins.
Plame's identity was exposed eight days after her husband publicly suggested in The New York Times and on NBC's "Meet the Press" that the administration distorted prewar intelligence to exaggerate the Iraqi threat.
To be allowed to pursue their effort to collect compensation, Plame's lawyers must show that Cheney and the other defendants are not immune from such suits.
The vice president "has a lot of the same attributes and considerations that relate to the president," Bucholtz argued, seeking to apply presidential immunity to the vice president.
The judge expressed concern the case might have to delve into classified information comparing Plame's circumstances with those of other CIA officers.
That's a "reasonable prospect," replied Bucholtz.
Chemerinsky pointed out that the government overcame classified information issues in the Libby case, which resulted in his conviction for lying to investigators about how he learned of Plame's identity and what he did with the information.
By: Lawyers for Vice President Dick Cheney, Karl Rove and two other Bush administration officials belittled Valerie Plame's lawsuit Thursday over the disclosure of her CIA identity.