A couple of recurring arguements are made to defend the practice of torture, one of which is that if it will save lives. Such a discussion often goes like this:
"So if some guy knows about an attack, and torture will get him to talk, it will save lives. So torture is OK then."
The fallacy of that point is it rarely is the case that the government knows exactly who knows of an impending attack. How is it that you are going to know the guy sitting in front of you has the information to save lives? These terrorist cells practice compartmentalization of information, so only a few will know enough details to tip off authorities. How could someone tell if they have that guy in custody? Of course, they won't.
So what are the options then? An interrogator could torture every person who hits the radar screen of suspicion. You know, just in case. And the whole time tell himself that he is saving lives. Another option is to choose someone who seems like a leader, and torture that guy until something good comes out. Of course, such things tend to be self-fulfilling prophesies.
This entire point of view is supported by the belief that people tell the truth under physical duress. How about that they will tell you anything to get the pain to stop? That seems more likely.