On the interplay between the issues of criminal culpability and prosecutorial discretion that Ramesh and I (here) discussed yesterday, a smart friend writes:

I agree that the issues are not really severable. As a legal matter, nobody knows the exact point at which increasingly aggressive techniques become “torture” within the meaning of the governing treaties and statutes. That is why, in the absence of anything really beyond the pale (amputations, electrocutions, and such), the President’s interpretation of those treaties and statutes should be entitled to deference; and it is why the doctrines of qualified immunity and lenity should bar the imposition of civil and criminal liability, respectively.
Moreover, none of the lawyers or policymakers currently under fire carried out any interrogation; the only criminal theory I can imagine would be aiding and abetting, which would require proof that the lawyer or policymaker at issue had a specific intent to facilitate the commission of torture, which seems to me all but impossible on the facts as we know them. In other words, the vagueness of the relevant legal standards, and the debatable nature of OLC’s legal conclusions (to put things rather uncharitably towards OLC), seem to me not only very strong merits arguments for the putative defendants, but also very strong prudential arguments against proceeding with inquiries that would be bad for the country in all of the ways that you suggest.
So, I think that “unfair to these individuals” and “bad for the country” are related points, and the force of the opposition to the witchhunt depends on teasing out both.