Well worth a read. You can download a PDF file of the 9/11 Commission executive director's thoughts on interrogation here. Money quote:
The moral question is subjective, of course. It is closely related to another question: What standard of civilized behavior should the United States exemplify, in a fight to preserve civilization against barbarism?
My own view is that the cool, carefully considered, methodical, prolonged, and repeated subjection of captives to physical torment, and the accompanying psychological terror, is immoral. I offer no opinion as to whether such conduct is a federal crime; merely that it is immoral. My moral standards are entitled to no special regard. My argument is not that others should adopt my morality. It is that the responsible policy officials should explicitly, thoughtfully, employ moral reasoning of their own. And, further, my argument is that the substitution of detailed legal formulations for detailed moral ones is a deflection of responsibility. Such deflections, often unconscious, are too common in our modern age.