CBS 's credibility as an objective news organization was destroyed by Dan Rather; beginning with his smart ass attitude toward Richard Nixon. He drove the final nail in the coffin with his bogus story about George W. Bush. (Why should anybody lie about Dubya? The truth is bad enough.)
Katie Couric is a competent reporter and news reader, but she apparently does not have the star power to pull CBS News out of the hole it's in, thanks to the dumb decision by executives not to fire Rather a couple of decades ago.