Andrew Sullivan zeroes in on an important point:
The reason this is vital is that it gets to the core of the question of good faith in authorizing the elaborate torture program that Bush and Cheney constructed as their central weapon in the war against Jihadist terrorism. If we can see that the memos were transparent attempts not to explicate the law in good faith to guide the executive branch – but were emanations of the executive branch to provide phony and flawed legal cover for already-decided illegal acts, then we have a conspiracy to commit war crimes.
Bush’s lawyers had heard stories about how FDR reshaped economic regulations, or about how Reagan tried to change abortion restrictions, and how both in the process had been doing nothing short of redefining the nation’s sense of what was and wasn’t constitutional. Their political mandate led them to overestimate their own power, while their reading of history led them to misjudge the plasticity of the law . I have argued that there should be a presumption of goodwill on the part of those who advocate for torture. But this should not persist in the face of evidence to the contrary. Moreover, I disagree with Andrew that good faith should determine their guilt or innocence. It hardly matters whether good intentions guided the actors in the Office of Legal Counsel. The Bush administration and its lawyers thought they could discard a basic human right in reshaping the law, and in doing so they violated their oath of office and international treaties. They should be prosecuted accordingly, regardless of how well-intentioned they were. The issue of “good faith” has little or no bearing.
Finally, please read all of what John Schwenkler has to say in this definitive post, where he explains the possibility of good faith and the reasons for pursuing justice.