If you don't mind watching an ad for Visa, this Salon series (Part 1 here) of articles is worth reading.
Every once in while clowns like Alan Dershowitz use torturous (pun intended) logic to justify officially sanctioned sadism. Sometimes it's almost amusing to listen to these justifications--they run along the lines of "BUT IF the terrorist had knowledge of the bomb that was set to explode, and IF we knew that 'forceful interrogation' would magically crush his capacity to resist and would result in said terrorist telling us the location of the bomb, when it was set to go off, and who his nefarious comrades were and where they were hiding, AND if it was YOUR KID'S SCHOOL that was at the epicenter AND your wife happened to be there for parent/teacher day AND if all it really took was a few minutes of holding said terrorist's hand on a hot plate for a minute or so...well, WOULDN'T you go ahead and do it?"
That's a lof of "ifs." So many that it makes me wonder how long these folks lie awake at night coming up with JUST the right scenario to justify their innate sadistic sides. Listening to justifications for torture tells you more about those making the argument than anything else.
Darius Rejali destroys the false logic of such justifications.
By all means, check out the articles if you have the time--especially Part II, which focuses on the systematic use of torture by the French in Algeria. It turns out that ONE useful bit of intelligence WAS obtained exactly ONCE: the army discovered that the French government was selling them out and secretly negotiating with FLN. The ensuing crisis brought down the Fourth Republic in 1958.