The issue with detainees is an interesting one and one that didn't have an easy answer (despite what you may read here and other places where crazy ideologues rant). The problem is/was that we didn't want them in civilian courts as common criminals, and we didn't want them covered under the Geneva Conventions as POWs. There were implications to either route that were less than optimal. So instead we simply made up a new procedure by which we made all new rules for detention. Those rules essentially were that we could ignore any and all other rules, and do whatever we wanted.
To me, it did stink of contrary to American principals. It was the easy way out. I believe the prisoners should have been either criminals or POWs, probably criminals. They could have had trials (since obviously we have evidence that their guilty otherwise we wouldn't be holding them, right?) and sent to jail. That’s the American system. Unfortunately that didn't happen. And those people were never given the same rights all other US prisoners are given and thus the whole torture thing.
To me, one should embrace the Constitution, even when it makes life more difficult, or perhaps costs lives. Once you allow yourself to ignore it for some justification, it's simply too easy to make new justifications each time you want to skip over someone or something's rights.
Now, as to the prosecution of ex-officials... I have a hard time seeing that go anywhere. I assume that acted in good faith and interpreted the law as they saw it. Baring fraud (and I have heard no indication that this could be fraud) I would see it as two competing legal theories, one of which was adopted, but the other of which isn't necessarily wrong. I bet the saber rattling will settle down and we will move on as a country.