As Rush was saying today, all roads seem to lead to Abilene, Texas, home of the infamous Bill Burkett, and the lovely and not-so-talented Robin Rather.
I would speculate, Burkett was the author and Robin was the point of contact with CBS, in coordination with the local 'rat organization and the DNC.
Robin Rather would indeed be a source Dan would characterize as "unimpeachable"
Rather may be a slug, but I'd bet even he would not roll over on his daughter.
Correction, perhaps not the home, but she is a known activist there.