Vicki Divoll [*], in an OpEd published in the New York Times, points out that there is no legally constituted body called "The Gang of Four" to begin with. Even assuming that the CIA did actually honestly brief Rep. Pelosi about the proposed use of waterboarding (it's not at all certain that they did) she was restricted from telling any of her colleagues about it. What was she supposed to do with the information if it was actually given to her?
The Constitution gives "...aggregate, not individual, powers to the legislative branch." The minority leader is relatively powerless in the first place. With the restrictions placed on communicating any information actually provided to any other member of Congress, there was nothing she could have done.
I'd also point out that there is no way of showing that the CIA actually told her anything. The so-called memo does not have any credibility since the CIA does not present the person who wrote it and placed it in the files. That could easily have been done last week, and with the CIA very invested in deflecting blame from themselves and also with the CIA populated by people whose normal job description includes large measures lying to the various publics to manipulate political responses, they are innately under suspicion. The fact that Sen. Mel Martinez also says he was not briefed on the use of actual torture techniques adds credibility to Rep. Nancy Pelosi's denial that she was briefed.
But the while the fact that Nancy Pelosi was briefed in a timely manner on the use of torture techniques by the CIA is very much in doubt, that doesn't matter. With the restrictions on her communication to other in Congress even if she was briefed, there was nothing she had any power to do with the information. The whole issue is right-wing deflection of blame from anyone who actually is responsible to someone else who could not have been responsible.
The real question is whether there was a crime committed (almost certain) and if so, who might be prosecuted for such a crime (less certain.)
A second and perhaps even more important question, as become whether Dick Cheney and his evil twin, David Addington, were actually attempting to justify the then proposed invasion of Iraq by torturing false confessions that purported to prove a link between Sadaam Hussein and al Qaeda. It is now well-known that torture does not elicit useful Intelligence. It instead forces the victim of torture to say whatever the torturer wants to hear just to make the torture stop. So while torture is effectively useless as an Intelligence-gathering tool, it is excellent for creating false confessions that can be used to justify actions the torturer wants the public to support.
It now appears that Dick Cheney's defense of torture as a way of gathering Intelligence is actually a cover-up of his office's pressure to torture confessions that justified Cheney's belief that Sadaam was allied with al Qaeda and had nuclear weapons. That makes the torture of prisoners at his clear direction the equivalent of the discredited "Italian Letter" that purported to show that Iraq was getting Yellow cake unranium to build nukes. In fact, the next question that should be revived was whether Ahmed Chalibi was the point-man who the Iranians used to run a highly successful Intelligence scam on Dick Cheney and his right-wing allies like the columnists/propagandists Bill Kristol and Charles Krauthammer.
Compared to all these real questions, the idea that because Nancy Pelosi might have been briefed on the CIA's use of torture techniques is nothing more than an irrelevant distraction. It is pure right-wing propaganda designed and pushed to prevent the real criminals from being identified and punished.
[*] Vicki Divoli is former CIA CTC deputy general counsel. She knows what she is talking about.
Laura Rozen has a very good analysis of all the events that have led to the current attacks on Nancy Pelosi and to her spirited pushback. The entire briefing process and its misuse and the lies apparently told by the CIA go back to the office of the Vice President and Dick Cheney.