In a move that will relive his ouster as anchor of the CBS Evening News and subsequent acrimonious departure from the network he called home for decades, Dan Rather has filed a $70 million lawsuit against CBS Corp. (NYSE: CBS), according to the New York Times.

The 75-year-old Rather obviously is bitter about how the network handled the investigation into how uncorroborated allegations about President Bush's service in the Air National Guard made it onto the air. In his lawsuit, Rather accuses CBS of committing fraud with its "biased" investigation that "seriously damaged his reputation," the Times says. Named in the suit are CBS president Leslie Moonves and Sumner Redstone, the media mogul who controls the company and its former parent Viacom Inc. (NYSE: VIA).

Oh brother.

Last week, I noted that the CBS Evening News had garnered its worst ratings in roughly two decades, with much of the blame falling on Katie Couric's shoulders (which are grazed by her impeccably highlighted hair). The post inspired several comments, both in support and in condemnation of Ms. Couric.

Today's New York Times weighed in on the issue, reporting that both CBS Corp. (NYSE: CBS) and Katie Couric have yet to throw in the towel. The new anchorwoman, who has been behind the desk for eight months, told the paper "Honestly, I think we're going to see ebbs and flows . . . I don't think it's a doom-and-gloom scenario."

Despite earlier rumors, Ms. Couric and CBS management continue to insist that she will not be heading anywhere -- not to another position with the network, not to the unemployment line -- until her five-year contract is fulfilled. Earlier speculation had suggested Couric might bow out following the 2008 elections. As CBS chairman Leslie Moonves noted, "This is a long-term commitment."

The eye network's nightly news offering is facing an uphill battle for the next four years and four months; a recent Gallup poll shows that 29% of respondents flat-out do not like Ms. Couric, compared to the just 51% who do. The nightly anchors for both Walt Disney's (NYSE: DIS) ABC network and General Electric's (NYSE: GE) NBC have less than 20% in the "don't like" camp.

CBS executives point out that the Evening News is still profitable. But for each 0.1-point slip in the ratings, industry experts say, revenue could drop as much as $6 million.

Beth Gaston Moon is an analyst at Schaeffer's Investment Research.