And that may be precisely one reason the "Killian" memos are ones he "wrote to himself" (and not on letterhead). While they concern military matters, they are no more official documents than would be his diary if it mentioned Bush's service.
http://story.news.yahoo.com/news?tmpl=story&ncid=762&e=1&u=/ap/20040926/ap_en_tv/tv_cbs_fallout
Viewership for the "CBS Evening News" during the week the Sept. 8 "60 Minutes" report on Bush's service was aired was down 8 percent from the same week in 2003, according to Nielsen Media Research. The next week, it was down 9 percent. ... "CBS Evening News" ratings are falling faster this year than either of its competitors. CBS is already a distant third to NBC and ABC, and the gap is getting wider.
... Privately, there's considerable sentiment that "the time has passed" for change, as one manager said.
"They need to phase Dan out in the most compassionate and appropriate way they can," said another executive.
"I don't think there's a connection there between him and the viewers we want any more," said a third. "I think the show needs an overhaul and generally what comes with an overhaul is a new face."