Commentators, such as Charles Krauthammer, "The Torture Debate, Continued", Washington Post, 2009-05-15 (Reprinted in Star Tribune, 2009-05-19) keep painting a scary scenario on how torture would prevent a terrorist attack, "the ticking time bomb" scenario.
In this scenario the authorities "know" there is a plot to do some dastardly deed, they have captured a suspect that they believe is involved in the plot, they believe they can only get details about the plot by torturing the suspect, and when the suspect reveals these details, they will be able to successfully foil the plot.
Like Krauthammer, they offer a real example in which they claim torture worked.
Unfortunately, there are no guarantees on any part of this scenario.
Some in the Clinton administration knew that Al Qaeda was planning an attack on the U.S. but didn't know exactly what. This information was given to the Bush administration and not followed up at high levels. See "Bush Administration's First Memo on al-Qaeda Declassified" and "Know thine enemy".
Some flight schools were suspicious of some of their students, for example, Zacarias Moussaoui, and reported them to the FBI. The local FBI office acted on these suspicions, but the Washington office denied permission to search Moussaoui's computer. It is uncertain how much Moussaoui knew about the 9/11 plot, but earlier action may have led to other Al Qaeda members.
Suppose Moussaoui had been tortured in order to reveal more details of the 9/11 plot. First, how much did he really know about that specific plot? Second, since he changed his story so many times, admitting guilt and denying guilt, could anything he said be believed? If he was to be part of the 9/11 plot, would he have admitted sufficient details under torture to foil the plot.
Years ago I heard a story about a Norwegian resistance member who was captured by the Germans. They knew he was involved with others and wanted to know their whereabouts. His interrogator drove a screwdriver into his knee and twisted, repeatedly. Despite the great pain, the Norwegian held out until he knew his friends, who were escaping Norway before being caught, were safely at sea.
So, for torture to successfully foil a plot, you have to know the plot exists, you have to know a captured suspect really knows sufficient details about the plot, and you have to be sure that he will reveal, under torture, sufficient details about the plot in a timely fashion. That is a very slender thread to hang the security of the nation on.
