Dan Rather, whose career at CBS News ground to an inglorious end 15 months ago over his role in an unsubstantiated report questioning President Bush's Vietnam-era National Guard service, filed a $70 million lawsuit this afternoon against the network, its corporate parent and three of his former superiors.

Mr. Rather, 75, asserts that the network violated his contract by giving him insufficient airtime on "60 Minutes" after forcing him to step down as anchor of the "CBS Evening News" in March 2005. He also contends that the network committed fraud by commissioning a "biased" and incomplete investigation of the flawed Guard broadcast and, in the process, "seriously damaged his reputation." As plaintiffs, the suit names CBS and its chief executive, Leslie Moonves; Viacom and its executive chairman, Sumner Redstone; and Andrew Heyward, the former president of CBS News.

In the suit, filed this afternoon in State Supreme Court in Manhattan, Mr. Rather charges that CBS and its executives made him "a scapegoat" in an attempt "to pacify the White House," though the formal complaint presents virtually no direct evidence to that effect. To buttress this claim, Mr. Rather quotes the executive who oversaw his regular segment on CBS Radio, telling Mr. Rather in November 2004 that he was losing that slot, effective immediately, because of "pressure from 'the right wing.'"