Second, there is the resource limit. For decades, guerrilla organizations have had "torture contracts" with their members: If you get arrested, keep the interrogators busy for 24 hours and let us change the passwords and locations. Give them false information mixed with half-truths. Make them waste their time and resources, and then after a day say whatever you want, since it will be useless then. Remember that you will become unconscious when the pain is extreme, and consider feigning unconsciousness.
Last, there's the psychological limit. The CIA Kubark manual notes that coercive investigation requires compiling a psychological profile, which can take days to write. Without a psychological profile, the manual says, torture is a "hit or miss" practice and "a waste of time and energy." Shot-in-the-dark torturing brings to mind the torturer's paradox. If he tortures first, he may be unable to get information by gentler means later. But if he tortures at the end, the prisoner may conclude that he is getting desperate and hold out longer.
Hardcore believers, including presumably the common terrorist, don't break quickly. Torturing them just gives them an excuse to prove that they're stronger than you. Even the Gestapo discovered that with members of the resistance in World War II: Few resistance fighters gave accurate information.
In fact, as George Browder explains in his powerful book "Hitler's Enforcers," "the Gestapo, like police anywhere, could not do its work without public support." The Gestapo's enormous success against the resistance, first in Germany and then elsewhere, depended heavily on bureaucratic files, police informants (G-men or V-men) and collaborators in foreign countries. "Increased reliance on interrogation through torture during the war years reflects the declining professionalism of an overextended staff much watered down with neophytes," Browder writes.
The priority in America's war on terror should be on developing human intelligence. Working one's way into a terror cell is not unlike working one's way into organized crime in the United States. One has to turn potential terrorists into double agents and to win the confidence and cooperation of the communities that shelter them. Technology is no substitute for this. Nor is torture.
Abu Ghraib should teach us what America's founders would have told us: that we are our own worst enemy. Leaders of dictatorships sign on to the Geneva Conventions only out of prudential fear of what other states might do to their POWs. Leaders of democracies sign on to them because they understand the evil that lurks in the heart of all human beings. Those who choose to abide by the rules do so not simply to restrain others but to restrain themselves.
Unrestrained power leaves behind a legacy of destruction that takes generations to undo. Torture, like incest, is the gift that keeps on giving. Democratic societies that legalized torture or tried to constrain its use have come to two ends. Some, like the Greeks and Romans, created tiered societies where authorities could torture whole classes of people (slaves or lesser citizens) and those who were beyond torture. Others, like the Italian city-states, were unable to prevent the executive branch from torturing more and more citizens and in the end fell to its dictatorial power.
The first result is hardly a model for modern democracies, and the second serves as a warning. In modern times, France routinized torture in Algeria, producing a racist, tiered society and an aggressive military government that almost overthrew French democracy. Proponents of torture would argue that destroying democratic institutions -- and the individuals involved -- is worth it if torture, as for the French in Algeria, succeeds in defeating terrorism.
Read Part 2: The example of military victory against terrorism by a democracy that used torture