Good Faith Beliefs and the law
The argument that, say, Richard Cheney isn't a criminal is based on the idea that and act is not a crime if one believes in good faith that it is necessary to save many lives.
Thus Cheney et al believed in good faith that Saddam Hussein was assisting al Qaeda and, when they insisted that torture be used to make al Qaeda captives admit this, they weren't using torture to get bogus evidence to support a lie, but seeking proof of what they were sincerely sure was a true statement. When they claimed that the Constitution put the President above the law, they believed it in good faith. When they decided that torture was needed, they believed it, even though (almost) everyone with any expertise told them it was counterproductive as well as criminal
I think a reasonable case can be made that Cheney is not guilty under the law, because he could not grasp the criminality of his actions. This legal approach has a commonly used name -- The Insanity Defence.
If I were a prosecutor I'd have no idea how to try to prove that Richard Cheney is not insane.