In Time, Matt Cooper writes about his conversation with Karl Rove that shows the Republican rebuttals to be as silly as they sound:
Rove did, however, clearly indicate that [Valerie Plame] worked at the “agency”–by that, I told the grand jury, I inferred that he obviously meant the CIA and not, say, the Environmental Protection Agency. Rove added that she worked on “WMD” (the abbreviation for weapons of mass destruction) issues and that she was responsible for sending Wilson. This was the first time I had heard anything about Wilson’s wife.
[..]
I have a distinct memory of Rove ending the call by saying, “I’ve already said too much.”
(Emphasis mine.)
“I’ve already said too much.” I believe that, in the law enforcement line of work, they call that a confession.