From ignoring the legal rights of detainees to the strategy of preventive war, people in and out of government were willing, in the interest of national security, to make exceptions to long-held prohibitions, to exempt the United States from international conventions and to exploit legal loopholes as they searched for information about potential terrorist attacks. In the Abu Ghraib prison scandal, the appalling results of this moral exceptionalism have become plain for all to see.

Abu Ghraib, however, is only the visible edge of a Boschian landscape of violation of the rights of innocents, prisoners of war and so-called enemy combatants. Since the scandal broke, military and press reports have identified numerous clusters of offenses from Afghanistan to Guantánamo, including other sites in Iraq and a gulag of secret C.I.A. prisons around the world. The torture, abuse and death under interrogation—39 cases of possible homicide are currently under investigation—are too widespread and systematic to be explained as the deeds of a few misguided enlistees and noncommissioned officers. They were part of a strategy of counterterrorism aimed at an elusive enemy in an allegedly new type of conflict.

The notion that the war against terror is radically different from any previous conflict was an ideological precondition to torture and abuse. The belief that new methods were needed to wage this new war and that customary limits on government and military operations might be lifted opened the way to moral confusion and ultimately, as Abu Ghraib has revealed, to depravity. Social psychologists who study wartime atrocities term such ideas “sanctions for evil.” The military personnel alleged to have engaged in torture, sadistic abuse and even homicide did not act in a vacuum, but in a climate that condoned harsh treatment of prisoners and suspects as legitimate behavior. However lax their training or their superiors’ enforcement of rules of conduct, the offenders shared a frame of mind with the makers of policy in Washington.

The administration generated a mind-set that traditional limits could be ignored to gather “intelligence” about terrorism and guerrilla operations. White House counsel Alberto Gonzalez defended the inherent right of the president, as a wartime commander-in-chief, to define enemy combatants and the condition of their detention. The Justice Department’s Office of Legal Counsel weighed the possibilities for interrogation methods that inflict near-lethal pain. Secretary of Defense Donald Rumsfeld issued a variety of judgments about the inapplicability or limited relevance of the Geneva Conventions. The C.I.A. established secret prisons and “renditions” (transfer of prisoners) to still less scrupulous foreign interrogators. As one decorated former military intelligence officer commented, attitudes toward treatment of the enemy “flow like a river—from top to bottom.”

Abu Ghraib demonstrates how mistaken it is to presume to make an exception out of fear of “a ticking time-bomb.” There is never just one exception. There is a slew of them, and under the pressures of war they cascade through the military, police and intelligence agencies, overwhelming any vestige of restraint. If respect for human dignity were not itself sufficient reason for resisting the temptation to torture and degrade possible enemies, then concern about the moral collapse brought about by exceptionalism provides a powerful reason for honoring standards of human rights protection. Making exceptions profanes the respect for the person on which American liberty rests, and it vitiates the moral integrity of those who serve our nation.

Torture and degrading treatment not only are wrong; they also don’t work. Veteran U.S. and Israeli intelligence agents have testified to the poor quality of intelligence extracted under torture. In a war on terror, moreover, the mistreatment of innocents and insurgent sympathizers swept up in mass arrests is very likely in the long run to lead to further resistance and increased terrorism.