Catholic leaders and academics have outlined the need for greater public discussion on the American policy of using drones to kill terrorists, saying it shouldn't be done "uncritically."

"I think it needs to be worked through and thought about...and I do think that we're rushing into drone technological warfare very rapidly, and certainly without public debate," said Dr. Christian Brugger, a professor of moral theology at Saint John Vianney Theological Seminary in Denver, Colo.

"This seems to be centered on executive policies which need considerable debating," he told CNA June 12, "so that the whole country can be involved in a way that it's not being involved right now."

Drones are remotely piloted, unmanned aircraft used for observation of prospective targets and for missile attacks on those suspected of terrorism. The U.S. drone program was begun by the George W. Bush administration, and expanded by President Barack Obama's.

The program has proved to be controversial, since many non-combatants, including U.S. citizens, have been executed by drones. On May 23, attorney general Eric Holder acknowledged that since 2009, four American citizens have been killed in drone strikes.

Among them were Abdulrahman al-Awlaki, the 16-year-old son of Anwar al-Awlaki, a member of al-Qaeda. Abdulrahman, who was born in Colorado, was killed by a drone in Yemen two weeks after his father had been himself killed in a drone attack.

Much of the discussion in Catholic circles of the use of drones focuses on just war theory, which governs the decision to go to war, as well as upright conduct of war. Just war theory's principles include the certain immanence of attack; whether the force used is proportional to the threat, and discriminates between combatants and civilians; right intention; and the likelihood of success in a military endeavor.

"The classical principles of just war theory don't seem to me, out of hand, to exclude the legitimacy of drones," Brugger said. Just because they may legitimately be used, however, "doesn't mean they are unqualifiedly justifiable."

Since U.S. drones have killed more than 800 Pakistani and nearly 100 Yemeni non-combatants, discussion of drone use has focused on right – or wrong – intention in the use of drones.

One way to have wrong intention and violate proportionality, according to Brugger, would be to intend the destruction of civilian population: "targeting non-combatants." The demoralizing effect of civilian deaths is always a temptation for military commanders, he noted, "for the sake of the good (military) results that might come from that."

In addition to non targeting non-combatants, those in charge of drone strikes must take care to avoid the death of innocent civilians. And yet, "foreseeability alone – seeing that civilians will die – that alone has never excluded the just war tradition from including as legitimate targets, military targets in which you foresee some civilians will be killed."

Thus there is a delicate balance that must be struck in the decision to make a belligerent act, and "due solicitude for avoiding civilian deaths is always required."

"You don't want to construe due care to avoid civilian deaths" to mean that "any foreseeing of civilian deaths renders the principle of right intention violated."

The balance between achieving necessary military objectives and avoiding civilian deaths has no "simplistic formula," Brugger emphasized. "This is where (you) would begin speaking about the virtues of prudential reasoning."

There is "a way of prudentially proceeding based upon general principles," Brugger explained, but there are no simple answers. Those making the decisions about drone strikes must be "formed by the virtue of justice" and of prudence, because "prudential reasoning becomes a safeguard from immoral choices."

"The big question much unintentional damage is legitimate to tolerate, in pursuit of a justifiable aim?"

Brugger said that this important part of moral analysis "is one of the issues in which we don't spend much time as Catholics." He noted that as a rule, Catholic moralists are "very caught up" in discussing intrinsic moral evils. "But there's a lot of immoral acts done that are not intrinsic evils...that's a big question in the field of moral analysis: how much harm is it licit to tolerate?"

With regard to this issue of unintended civilian deaths, Brugger suggested that "the same kinds of leeway we would give to historic armies" attacking military targets "and yet ending up with the collateral damage of innocent civilians" should be afforded to the use of drones.

While not automatically excluding drone warfare, Brugger expressed discomfort with it because the drone operators may be quite removed from the conditions of war. When the effects of an attack are thousands of miles away from the operator – as in the case of drones – it removes a "safeguard" on proportionality: "the temptation to go in excess of what is reasonable would be greater" because of the virtual nature of the weapon.

Bishop Robert E. Pates of Des Moines agreed that "our usage of this technology far outstrips the amount of reflection we've done on the subject." In a June 4 column at The Washington Post, he asserted that "drones aren't the murky moral subject we pretend they are."

Bishop Pates' objection to drones focused on the likelihood of success, saying, "it's easy to make the case that drones push us farther from peace" and actually contribute to extremism and anti-American sentiment.

A June 7 report by Al Jazeera explains that in one Yemeni village, Khashamir, drone strikes killed al-Qaeda militants as well as an imam who had delivered forceful sermons against extremism.

"The repercussions were devastating," Al Jazeera reports. "The villagers marched the next day, chanting: 'Obama, why do you spill our blood?'"

Bishop Pates said the radicalization resulting from drone warfare "makes it difficult to justify targeted killings," and that the fact they are conducted in countries with which we are not at war makes "the moral justification for drones even more remote."

The bishop also drew attention to the psychological harm drones have on those who operate them remotely, noting that the Air Force says that nearly half of drone operators report high levels of stress.

"They observe their targets for days on end, becoming intimately familiar with their lives, before making the life-or-death decision. We should be more concerned with humanity, including people in countries very far away and with lives that seem different from our own."

Doctor Terry Wright, a philosophy professor at St. John Vianney, told CNA/EWTN News that because the war on terrorism doesn't have a clear definition of success and termination, "just war theory...doesn't fit it very well."

Wright's primary concern regarding the drone attacks has been the targeting of U.S. citizens. He noted that while those who represent an immediate threat can justly have their right to due process violated, "somebody who possibly could have a plot against the U.S. is not in that sort of immediate threat situation."

"And if you're an American citizen, the Constitution seems to say you're entitled to due process before you're executed."

Brugger agreed that due process concerns, while not a problem in just war theory, are legitimate, and that the consequences of targeted killing – whether or not it actually leads to a just outcome – is "certainly a legitimate source of moral analysis."

Regarding Bishop Pates' concern for the high number of civilians killed by drones, Brugger returned to the point that "it's easy to violate the principles of upright intention when you're so far removed" from the effects of the attack.

"An irresponsible formulating of targets, without concern for non-combatants, which could be easier to do at a distance, would be a violation of right intention, because we need to exclude from our intention, civilians."

Having said all this, Brugger emphasized that "the desire for a simple answer to drones is unrealistic. I don't think Catholics are going to find a yes or no answer to it, we'll just have to struggle with it more than that...drones are one of these frontiers of moral reasoning that we haven't given due time and depth to."

"There are open questions," he said, and it would be premature – "in excess of what we know" to assert out of hand that drones are justifiable or not, "in terms of just cause or proportionality or intentionality."

The imperative "do justice," Brugger noted, doesn't lead to conclusions in the abstract, but only in concrete situations. "That's what we're talking about right now."