(UNDATED) While elected officials and cable-news pundits have been debating whether torture of suspected terrorists is effective, legal or constitutional, a moral question has loomed in the background: is torture ever justified?

Most Americans say yes. A Pew Research Center survey of 742 Americans in April found that 71 percent believe torture of suspected terrorists is justified, at least on rare occasions. Solid majorities of every subgroup, including religious affiliation and worship attendance, said torture could be justified.

Ethicists and other thinkers are weighing under what conditions, if any, torture could be acceptable. What’s emerging is a rough outline of what could be termed a “torture doctrine,” vaguely reminiscent of Christianity’s 1,500-year-old Just War theory.

With torture, however, the query centers not so much on when it’s just — since few public intellectuals regard torture as a just practice — as when it might be needed and defensible.

Just War theory starts with a number of questions — is war really necessary? Is it likely to succeed? Are there other alternatives? Here’s how similar questions might apply to moral dilemmas surrounding torture:

Is torture ever permissible?

No, according to the Rev. Richard Killmer, executive director of the National Religious Campaign Against Torture, a coalition of more than 250 religious organizations.

Torture “is a violation of the respect and honor that every human being is entitled to,” Killmer said. There are better methods, including appealing to suspects’ humanity and the idea that needed information “might be important to saving innocent lives.”

Others disagreed. Michael Levin, a philosopher at City University of New York, said he stands by his 1982 essay, “The Case for Torture.” In it, he argues: “there are situations where torture is not merely permissible but morally mandatory.”

And it’s not just Americans, Levin argues, who could find justification for using torture to prevent future harm.

“If Americans are planning to level a neighborhood of Baghdad,” he wrote in an e-mail, “killing dozens of innocent people to kill a few members of the resistance, and the resistance gets hold of an American soldier who might know what neighborhood the Americans are planning to destroy, they are allowed to torture the information out of him.”

For those with a utilitarian philosophy — the idea that the moral course is the one that accomplishes the greatest good for the greatest number of people — torture may at times seem justifiable. The conditions, however, can vary.

Is the detainee conspiring to commit a heinous crime, such as mass murder?

John Kleinig, director of the Institute for Criminal Justice Ethics at John Jay College in New York City, posed a hypothetical scenario: What if a bomb were sure to go off and kill many unless officials were able, through the use of torture, to obtain information essential to defuse it?

“We are never going to be in position to know what the ticking-bomb argument requires that we know,” Kleinig said in an e-mail. Officials would have to know, for instance, that a real bomb will certainly go off unless defused, but he expects such certainty isn’t ever going to transpire in real life.

Levin, however, notes that guilt is sometimes obvious. “`Clear guilt’ is difficult to define,” he writes in his 1982 essay, “but when 40 million people see a group of masked gunmen seize an airplane on the evening news, there is not much question about who the perpetrators are.”

Would torture yield better information than any other method?

The notion that torture generates useful information is widely contested. President Obama, among others, has rejected the idea on the grounds that the tortured will presumably say almost anything to make the pain stop.

Yet even those who oppose torture on moral grounds say they nonetheless consider the prospects of securing high-quality information in certain cases.

“If I were the mother or grandmother of a child who might have been saved had information been garnered concerning a bomb placed in a school, I would no doubt be very angry that harsh things weren’t done,” said Jean Bethke Elshtain, a University of Chicago political philosopher. “After all, if one saw a person running into the school with a bomb, he could be shot dead on the spot. Still, there is something in me that says `no’ — a decent, human rights-respecting society cannot go down this path, no matter what the provocation.”

Would innocent lives likely be saved as a result of torture?

“If life is so valuable that it must never be taken,” Levin argues, “the lives of the innocents must be saved, even at the price of hurting the one who endangers them.” He compares torture to assassination and pre-emptive attack — that is, “an acceptable measure for preventing future evils.”

Some worry, though, about an ends-justify-the-means morality that legitimizes something reprehensible on the grounds that it could save innocents. Ronald Hallman, director of the criminal justice program at Roberts Wesleyan College in Rochester, N.Y., offered the example of dropping atomic bombs on Hiroshima and Nagasaki to end World War II. At the time, it was justified as a way to spare American lives and bring the war to a swift end.

“Can we sit here today and say, `Well, that was the right thing to do because we saved all those lives?’ Maybe,” Hallman said. “But we’re now the only country that’s ever used a nuclear weapon. That bothers me a lot. It’s hard for me to morally justify actions that torture, injure or potentially kill people except under the most extreme conditions.”

Is there no alternative?

Hallman said torture is morally wrong in all cases because it violates another person’s God-given dignity. But in the spirit of never saying never, he left open the door for a hard-to-imagine case when it might be both wrong and necessary: torture as the lesser of two evils.

He says torture might be warranted “when there is no alternative, which doesn’t happen very often, but it is possible.”

Elshtain made a similar point. She noted how Lutheran theologian Dietrich Bonhoeffer plotted to kill Adolf Hitler, even though he knew planning to take a human life — even Hitler’s — was morally wrong. But Bonhoeffer suggests in his “Ethics” text that necessity sometimes prevails.

“Harsh necessity may require harsh measures,” Elshtain said. “There are things that one should NOT try to justify — terrible and tragic things … one throws oneself on God’s mercy and seeks forgiveness, for one is certainly a sinner.”