The abuses at the Abu Ghraib prison in Iraq stand out for their pointlessness as well as their cruelty. Done in the name of collecting intelligence about insurgents, this brand of brutality has surely created more of them. Sodomy with a chemical light, threats of rape, a female soldier posing gleefully next to a stack of naked male prisoners, beatings with a broom handle, to say nothing of the possible murders: These are the techniques of sadistic amateurs, not of intelligence experts. That’s why their criminality is so obvious. 

But the photographs of Abu Ghraib have also forced into the spotlight some hard questions with less obvious answers. Reports have surfaced since 2002 of U.S. forces torturing or near-torturing prisoners in Afghanistan, with at least two possible homicides. But President Bush and Defense Secretary Donald Rumsfeld have previously ignored such abuses while disdaining the international-law rules designed to prevent them. Meanwhile, Congress and the public have averted their eyes from questions such as these:

How can we get potentially lifesaving information from suspected terrorists without trashing human rights and staining our souls? Is torture ever morally justifiable? Is it ever legal? Should it be legal? What about less extreme forms of coercive interrogation, which range from polite but persistent questioning to covering prisoners’ heads with black hoods, keeping them naked in cold, damp cells, depriving them of sleep, denying them adequate food, forcing them into uncomfortable "stress" positions, and threatening to kill them or their families? Does the use of such coercive interrogation techniques — which the Pentagon appears to have authorized in at least some contexts — lead inevitably to crimes such as those at Abu Ghraib?

Here are some proposed answers.

• Torture may be justified in rare, mostly hypothetical cases. It is tempting to say that torture is always wrong, period. Beating prisoners unconscious, breaking their bones, burning them with hot irons, shocking them with cattle prods, pulling out their fingernails, or similar practices are viscerally horrifying to civilized people and condemned by the moral codes of all civilized societies.

But what about the "ticking-bomb" hypothetical used by law professors to confound their students: If the government captures a Qaeda terrorist known to have planted a bomb timed to explode in a crowded area within three hours, would it not be justifiable to try to do whatever it takes to get the location out of him?

And what about Qaeda leaders such as Khalid Shaikh Mohammed, who appears to have directed the 9/11 attacks and who knew of many planned attacks at the time of his capture last year? Such cases "pose one of the strongest arguments in modern times for the use of torture," Mark Bowden wrote in The Atlantic Monthly last October, because "getting at the information they possess could allow us to thwart major attacks, unravel their organization, and save thousands of lives."

And what about the Qaeda member caught by Philippine intelligence agents in 1995 in a Manila bomb factory? Defiant through 67 days of savage torture — most of his ribs broken, cigarettes burned into his private parts — he finally cracked when threatened (falsely) with being turned over to Israel’s Mossad. And he revealed the so-called "Bojinka" plot to crash 11 U.S. airliners and 4,000 passengers into the Pacific, to fly a private Cessna full of explosives into the CIA’s headquarters, and to assassinate Pope John Paul II.

• Even so, torture is almost never justifiable in real life. There are at least three reasons. First, it will rarely if ever be knowable in advance that torturing a particular suspect is likely to save innocent lives. Many suspects have no information of great value. Even leaders such as Shaikh Mohammed may have only stale information, or may not break, or may concoct false leads, or may be more susceptible to less brutal interrogation techniques designed to create a sense of dependency and trust.

Second, official approval of torturing a few especially "high-value" suspects would lead in practice to the torture of dozens or hundreds of others — including innocent civilians mistakenly suspected of terrorism — while unleashing the most sadistic impulses of those involved. The horrors of Abu Ghraib were openly celebrated by the perpetrators despite clear criminal prohibitions. Imagine what would happen without such prohibitions.

Third, using torture might well cost many more American lives than it would save, by feeding the rage of those who see Americans as sadistic, hypocritical, anti-Muslim imperialists and thus driving more recruits into the terrorist murder brigades — as the Abu Ghraib barbarities have surely done.

• Torture is always illegal, and should be. Both federal and international law are crystal clear in banning any and all use of torture — including torture of terrorists — although the law is unavoidably ambiguous in defining torture. The United Nations Convention Against Torture, which the Senate ratified in 1994, with Congress providing criminal penalties for violators, bans intentional infliction of "severe pain or suffering, whether physical or mental." Military law contains similar prohibitions. And President Bush pledged in June 2003 to lead the world in "prohibiting, investigating, and prosecuting all acts of torture," although, after Abu Ghraib, his words have a hollow ring.

Should the law recognize an exception for cases involving ticking bombs or terrorist kingpins such as Shaikh Mohammed? No, because there is no tolerable way to finish this sentence: "Torture is prohibited except when … " That’s why Israel’s Supreme Court, which has wrestled long and hard with the moral quandaries at the intersection of terrorism and torture, has banned all forms of torture, including the violent shaking of captives. At the same time, the Israeli court has condoned other types of coercive interrogation and has suggested that there might be an "emergency conditions" defense for any cases in which security personnel honestly believed that illegal use of force was the only way to prevent imminent terrorist murders.

The best way to minimize the conflict between the need for aggressive interrogation and the prohibitions of human-rights law may be to define "torture" narrowly enough on a case-by-case basis to leave considerable leeway for tough, coercive interrogation short of excessive brutality.

• Coercive interrogation of suspected terrorists is arguably legal but should be strictly controlled. The 1949 Geneva Conventions, as incorporated by the U.S. military’s Law of Land Warfare, ban "any … form of coercion" or "unpleasant or disadvantageous treatment" to get information from prisoners of war. These laws give even broader protection to noncombatants.

But the Bush administration claims that these rules do not apply to terrorists. This view, although disputed by many human-rights activists and scholars, seems right. (The administration has been quite wrong, however, in denying detainees who claim to be POWs or noncombatants a chance to present their evidence to military tribunals, as the Geneva Conventions clearly require.) As a legal matter, terrorists and others who target civilians are "unlawful combatants" with no right to the elaborate protections of the Geneva Conventions. As a practical matter, undue fastidiousness in interrogating terrorists could lead to the preventable murders of thousands of people.

Far from being unduly fastidious, some of our military and intelligence personnel have used brutal coercion, up to and including torture, on large numbers of prisoners who were apparently not terrorists. The only way to control such excesses is to make it clear that from now on, they will not be tolerated. And the only way to do that is to impose tough criminal penalties on those responsible and to end the careers of those who have turned a blind eye or fostered a culture of lawlessness. Whether the latter category includes Rumsfeld is a question that Bush should carefully consider and that Congress should investigate.

I have so far ducked the hardest question of all: where to draw the line between prohibited torture and permissible coercion. The honest answer is that the locus of that line may vary from one case to the next. If, as seems quite possible, Shaikh Mohammed was held naked and hooded in a cramped, bone-chilling cell, prevented from sleeping, and forced into uncomfortable positions to get him to talk, I would approve, and I would strain to avoid calling it torture. When the same is done to ordinary Iraqis who may or may not be anti-American insurgents, it is an outrage, and it would be odd to quibble with those who call it torture.

This is, I confess, unfortunately inconsistent. But which of the alternatives would you prefer? A government-sanctioned torture system? Or a free pass for captured terrorists to keep their murderous secrets?