This is the essence of the problem. To Dan Rather and to a lot of other powerful members of the chattering class, that which is right of center is conservative. That which is left of center is middle of the road. No wonder they can't recognize their own bias.
Bias: A CBS Insider Exposes How the Media Distort the News (2001)
It doesn't happen that way.
Response to a student asking if he ever met a conservative who became a liberal.
I consider myself to be an old-fashioned liberal. I'm a liberal the way liberals used to be when they were like John F. Kennedy and when they were like Hubert Humphrey. When they were upbeat and enthusiastic and mainstream. I am not a liberal the way liberals are today at least as exemplified by Al Franken and Michael Moore, where they're angry, nasty, closed minded, & not mainstream, but fringe.
The big 3 networks don't like the fact that there's a Rush Limbaugh out there, they don't like the fact that there's a Fox News, they don't like the fact that there's a Matt Drudge. They liked it when it was nice, when it was just the three of them. Well, it ain't that way anymore.
Mandaville, Michael. Citizen-Soldier Handbook: 101 Ways Every American Can Fight Terrorism. pg. 227