If you ever come across the book "In Search Of Deepthroat", pick it up. It makes a very strong case that Buchanan is Deepthroat, especially now that most of the other possible suspects are dead yet Burnstein still won't disclose the name because Deepthroat is still alive.
It would certainly be in character for buchanan...selling his own people out for personal gain. It might also explain how a third rate speech writer got his foot in the media door at a time when conservatives weren't that welcomed.