I’m sure this has been covered elsewhere, but let’s be clear. The moment CBS admits these docs are bogus, theymust divulge who their source was. Protecting sources who tell the truth is honorable (though not as sacrosanct as some in the press think). Protecting sources who gave your news organization an umbrella enema and then opened it, is nuts. You have no obligation to protect a source who lies to you. Indeed, you have an obligation to out such sources. The only plausible motive I can think of for why Rather et al would protect the source of these documents — once they admit the truth — is that the source of these docs is even more embarassing than the fraudulent nature of the documents themselves. If it’s Chris Lehane or Ben Barnes or someone else tied to the Kerry campaign, CBS News will have actively aided and abetted a partisan smear. And they can’t afford to admit that.
Look at it this way: Assuming CBS comes clean, imagine if Karl Rove were the source. They’d admit it in a heart beat.