Scarborough and others (some in the comments here) have brought up the fact that some members of Congress, including the Gang of Four and Nancy Pelosi, were briefed on the Bush administration's torture policy back in 2002.
To which I respond: Yeah. So? From the Washington Post, circa late 2007:
Congressional officials say the groups' ability to challenge the practices was hampered by strict rules of secrecy that prohibited them from being able to take notes or consult legal experts or members of their own staffs. And while various officials have described the briefings as detailed and graphic, it is unclear precisely what members were told about waterboarding and how it is conducted. Several officials familiar with the briefings also recalled that the meetings were marked by an atmosphere of deep concern about the possibility of an imminent terrorist attack.
Members of Congress were briefed, but had zero veto power over what they were hearing and, as is evident here, they didn't have the president's luxury of legal counsel to consult on the procedures. Additionally, had they blown the whistle on torture in 2002, what proof could they have presented? No notes. No memos. Nothing on paper. Just their word in a midterm election year against the word of a president with approval numbers in the gazillion percentile.
Consequently, they would've been publicly tarred, feathered, disgraced and perhaps prosecuted by the Bush Republican machine -- including the establishment press which was loudly dittoing the administration's "smoke out the terrrrsts no matter what" agenda.
(Thanks to Silly Ratfaced Git in the comments.)