Judicial Hearing Officer Ira Gammerman on Thursday allowed the lawsuit to go forward, but struck down the parts of the suit that name Viacom Chairman Sumner Redstone, CBS President Leslie Moonves and former CBS News President Andrew Heyward.
A lawyer for the defendants, lead outside counsel James Quinn, said the judge's ruling eliminated Rather's core complaints of fraud and breach of good faith and fair dealing.
The lawyer said it was hard to see how the ex-anchor's assertion of a conspiracy between CBS and the Bush administration "will have any traction going forward."
Dan Rather's lawyer, Martin Gold, forcefully disagreed with the defense's characterization of today's motion.
"It's not a setback at all," Gold told CBS News legal analyst Andrew Cohen. "The biggest shock that I had was when I read Jim Quinn's statement…in which he said that it was a great victory for them and all that's left is a garden variety contract dispute, those were his words, and that's just nonsense."
Gold told Cohen that he still planned on deposing all three of the individuals whose names were eliminated from the complaint: Redstone, Moonves and Heyward.
"They were the people who acted on behalf of the company," Gold said, "Corporations act by human beings. Those are some of the major people who functioned on behalf of the company and they have to be deposed."
CBS said in a statement: "We are gratified that the court has dismissed the majority of Mr. Rather's claims, including the spurious claims against Mr. Redstone, Mr. Moonves and Mr. Heyward. With respect to the few remaining claims, relevant to his contract, there are no facts to support them and we expect them to be dismissed when the discovery process is complete."
Rather's last months at CBS News were clouded by a disputed story on President Bush's Vietnam-era military service. Rather says his employers made him a "scapegoat" to placate the White House after questions arose about the story.
Quinn told CBS News' legal analyst Andrew Cohen that the contract issue left relates to "whether or not we 'benched' him and whether he had sufficient time on 60 Minutes and 60 Minutes II after he stepped down as the anchorperson."
Rather narrated the September 2004 report that claimed President Bush skirted some of his duties during his National Guard service and that a commander felt pressured to sugarcoat Bush's record. He maintains the story was true.
But an independent review for the network determined the story was neither fair nor accurate. CBS fired a producer for airing it, and three news executives resigned.
Viacom Inc. is CBS's former parent company.