Ah, those were the good old days: when warfare was simple, fair, brutal and stupid!

The C.I.A. drone killing of Anwar al-Awlaki, an American citizen who was also an Al Qaeda leader, is raising multiple ethical controversies that pollute each other,  making ethical coherence all but impossible.

The issues:

• The target was an American citizen. Whatever his crimes, shouldn’t he have the right to a trial before being summarily executed?

• There is no conclusive proof that he actually did anything that resulted in violence against Americans, or posed an imminent threat to national security. Was he targeted for his words, rather than his conduct? How can it be legal or ethical for the U.S. to target a citizen for death because of his political views?

• The United States has officially forsworn assassination as a military or intelligence tactic. Yet this appears to have been one.

•   Yemen is not a field of combat, and there was no imminent threat to human life creating an exigency to require U.S. forces to target someone there, whether he was a citizen or not.

• Using unmanned drones in warfare is ethically troubling.

Add to all this the inherently murky and eternally debated ethical nature of warfare itself, the fact that international terrorist organizations blur the existing definitions between military and criminal action, together with the mind-numbing ambiguities of international law, and we have a complex situation in which there is little agreement on terms, concepts, standards and values, much less how they apply to Anwar al-Awlaki’s death.

I am far less confident of a conclusion that the killing was legal than I am that the killing was ethical in a situation where traditional rules and considerations don’t fit the situation well, meaning that decision-makers must go outside the rules to find the right, meaning ethical, course of action.  And I’m even not 100% confident of that.

The A.C.L.U., Rep. Ron Paul, various scholars and war-opposing pundits immediately declared the drone-killing of an American citizen ethically and legally unconscionable. They point out that the Constitution forbids the taking of a citizen’s “life, liberty, or property, without due process of law,” and thus Awlaki, who had not been convicted in a court and wasn’t engaged in active combat American soldiers, was really a victim of illegal, state-sanctioned murder.

This is a wonderful example of why the Constitution needs to be interpreted according to how it applies to modern realities, rather than the world as it was understood in the 18th Century. Al-Qaeda’s version of “combat” is something that the Founders could not imagine — meticulous, long-term planning of terrorist attacks.  The terrorist organization doesn’t send in armies or exchange fire.  Yet a leader of such a group is still involved in active hostilities against its target, and if the United States is the target, the leader’s status as a citizen should not trump his activities as an enemy combatant.

The Union under Abraham Lincoln didn’t hesitate to kill Confederate soldiers who it regarded as traitorous citizens during the civil war. The C.I.A. and President Obama concluded that Awlaki posed an imminent threat. One can disagree with that call, but once that call was made, the detail that the imminent threat working with a terrorist organization that is involved in the equivalent of war with the U.S. happened to be a U.S. citizen should not have cloaked him with special protection by the Constitution.

The legal argument against so-called U.S.-ordered assassinations is based on Pres. Ford’s executive order banning them. Ford’s order has always struck me as a P.R. move by the government, more form than substance, because the prohibition can be waived with a president’s approval. A prohibition that can be waived isn’t really a prohibition at all. The order just makes certain that the C.I.A. doesn’t go around assassinating foreign leaders and other perceived enemies of the U.S. on its own. If the President agrees that an assassination is in the best interests of the nation, then suddenly the assassination is legal. And, if that assessment was fair, it is ethical as well.

The ethical arguments against assassinations in wartime have never made any sense to me. It seems to be a tool of warfare that meets all utilitarian requirements. Targeting the leader of a nation or organization at war with the United States can save lives on both sides and shorten the conflict; the traditional prohibition against it seems to have developed as a gentleman’s agreement between wartime leaders to make sure only soldiers and civilians got killed, not the fools who started the wars. Would it have been unethical for the U.S. to target Adolf Hitler for assassination? Does anyone doubt it?

The Yemen argument, that there is no legal basis for killing a non-combatant who is in a country that is not at war with the U.S., may have a basis in international law but is ethically unpersuasive in a case such as this. An organization like Al-Qaeda can operate in many locales simultaneously, and the traditional restrictions on where a combatant can be killed are illogical given modern communications methods.  If Awlaki could help Al-Qaeda wage war against the U.S. from Yemen, and he could and did, there is nothing unethical about targeting Awlaki in Yemen.

Finally, we have the C.I.A. killer drones, the remote-controlled armed aircraft that have ignited an ethical controversy that this episode only raises to a new level. The “drones are unethical” advocates are really “war is unethical” absolutists: their assumption is that anything that makes warfare less dangerous to U.S. forces is wrong, because it reduces opportunity for American casualties to turn public opinion against the conflict in question. It is a variation on “comedian” Bill Maher’s argument that U.S. pilots who bombed Bosnia were cowards while the 9-11 suicide bombers were courageous, descendants of the older arguments that missile warfare, and long before that, snipers, are unethical.

Pacifists would prefer their wars, if they have to exist at all, to be Napoleonic exercises that would guarantee maximum mayhem and self-evident stupidity, with mutual suffering that would guarantee maximum critical news coverage and the public forced to confront its human costs rather than receive antiseptic reports of its strategic benefits. Efficient war is unethical war.

That is an ideological position divorced from reality. If a C.I.A. drone could have killed Osama Bin Laden before September 11, 2001, the world would be a better and safer place, and it is a better and safer place now that Anwar al-Awlaki—an American citizen in name only who was actively part of a hostile organization dedicated to killing Americans—is dead.

President Obama did the right thing.