With the Catholic Church, of all things, turning against the doctrine that maintains there can be a "just war," it's worth taking a serious look at the thinking behind this medieval doctrine, originally based in the divine powers of kings, concocted by a saint who actually opposed self-defense but supported slavery and believed killing pagans was good for the pagans -- an anachronistic doctrine that to this day still outlines its key terms in Latin.
Laurie Calhoun's book, War and Delusion: A Critical Examination, casts an honest philosopher's eye on the arguments of the "just war" defenders, taking seriously their every bizarre claim, and carefully explaining how they fall short. Having just found this book, here is my updated list of required reading on war abolition:
A Global Security System: An Alternative to War by World Beyond War, 2015.
War: A Crime Against Humanity by Roberto Vivo, 2014.
War and Delusion: A Critical Examination by Laurie Calhoun, 2013.
Shift: The Beginning of War, the Ending of War by Judith Hand, 2013.
The End of War by John Horgan, 2012.
Transition to Peace by Russell Faure-Brac, 2012.
Beyond War: The Human Potential for Peace by Douglas Fry, 2009.
Living Beyond War by Winslow Myers, 2009.
These are the criteria Calhoun lists for jus ad bellum:
- be publicly declared
- have a reasonable prospect for success
- be waged only as a last resort
- be waged by a legitimate authority with right intention, and
- have a cause both just and proportional (sufficiently grave to warrant the extreme measure of war)
I would add one more as a logical necessity:
- have a reasonable prospect of being conducted with jus in bello.
These are the criteria Calhoun lists for jus in bello:
- only proportional means to sound military objectives may be deployed
- noncombatants are immune from attack
- enemy soldiers must be respected as human beings, and
- prisoners of war are to be treated as noncombatants.
There are two problems with these lists. The first is that even if every item were actually met, which has never happened and can never happen, that would not make the mass killing of human beings moral or legal. Imagine if someone created criteria for just slavery or just lynching and then met the criteria; would that satisfy you? The second problem is that the criteria are, as I've mentioned -- just as with President Obama's similar, extra-legal, self-imposed criteria for drone murders -- never actually met.
"Publicly declared" seems like the one item that might actually be met by current and recent wars, but is it? Wars used to be announced before they began, even to be scheduled by mutual agreement of the parties in some cases. Now wars are, at best, announced after the bombs have begun falling and the news become known. Other times, wars are never announced. Enough foreign reporting piles up for diligent news consumers in the United States to discover that their nation is at war, via unmanned drones, with yet another nation. Or a humanitarian rescue operation, such as in Libya, is described as something other than a war, but in a manner that makes clear to the critical observer that yet another governmental overthrow is underway with chaos and human tragedy and ground troops to follow. Or the serious citizen researcher may discover that the U.S. military is helping Saudi Arabia bomb Yemen, and later discover that the U.S. has introduced ground troops -- but no war is publicly declared. I've asked crowds of peace activists if even they can name the seven nations that the current U.S. president has bombed, and usually nobody can do it. (But ask them if some unspecified wars are just, and lots of hands will shoot upward.)
Do any wars "have a reasonable prospect for success"? That may depend in some exceptional case or cases on exactly how you define "success," but clearly very nearly all U.S. wars of the past 70 years (and there have been many dozens) have been failures on their own basic terms. "Defensive" wars have created new dangers. Imperial wars have failed to build empire. "Humanitarian" wars have failed to benefit humanity. Nation building wars have failed to build nations. Wars to eliminate weapons of mass destruction have been waged in places where such weapons didn't exist. Wars for peace have brought more wars. Nearly every new war is defended based on the possibility that it could somehow be like a war that was waged over 70 years ago or like a war that never happened (in Rwanda). After Libya, those same two excuses were used again in Syria, with the example of Libya consciously erased and forgotten like so many others.
"Waged only as a last resort" is central to jus ad bellum, but has never been met and can never be met. There is quite obviously always another resort. Even when a country or region is actually attacked or invaded, nonviolent tools are more likely to succeed and are always available. But the United States wages its wars offensively abroad. (Calhoun points out that the 2002 National Security Strategy included this line: "We recognize that our best defense is a good offense.") In these cases, even more obviously, there are countless nonviolent steps always available -- and always preferable as in fact, in war, the worst defense is a good offense.
"Waged by a legitimate authority with right intention," is a pretty meaningless criterion. Nobody has defined what counts as a legitimate authority or whose professed intentions we should believe. The main purpose of this criterion is to distinguish whichever side of a war you're on from the other side, which is illegitimate and evil intentioned. But the other side believes just the opposite, just as baselessly. This criterion also serves to permit, through the Fallacy of Medieval Monkish Bullshitting, any and all violations of the criteria of jus in bello. Are you slaughtering lots of non-combatants? Did you know you were going to? It's all perfectly fine as long as you state that your intention was something other than murdering all those people -- something your enemy is not permitted to state; your enemy can in fact be blamed for allowing those people to live where your bombs were falling.
Can a war "have a cause both just and proportional (sufficiently grave to warrant the extreme measure of war)"? Well, any war can have a wonderful cause, but that cause cannot justify a war that violates all the other criteria in this list as well as the basic demands of morality and law. A just cause is always best pursued by means other than war. That a war was fought prior to ending slavery doesn't alter the preferability of the course many nations took in ending slavery without a civil war. We wouldn't justify killing each other in big fields now, even if we ended fossil fuel consumption afterwards. Most causes that can be imagined or for which we are told actual wars are fought, don't involve ending or preventing anything remotely as bad as war. World War II, prior to and during which U.S. and British officials refused to rescue the Nazis' future victims, is often justified by the evil of killing people in camps, even though that justification arose after the war, and even though the war killed several times as many people as the camps.
Why did I add this item: "have a reasonable prospect of being conducted with jus in bello"? Well, if a just war must meet both sets of criteria, then it must not be launched unless it has some hope of meeting the second set -- something no war has ever done and no war ever will do. Let's look at these items:
"Only proportional means to sound military objectives may be deployed." This can be met only because it is completely meaningless, all to be self-servingly shaped by the eye of the war-monger or the victor. There's no empirical test to allow a neutral party to declare that something is or is not proportional or sound, and no war is known to have been prevented or significantly restrained by such a test. This criterion can never be met to the satisfaction of victims or losers.
"Noncombatants are immune from attack." This may never have been met. Even scholars opposed to war tend to focus on past wars between wealthy nations rather than past wars of elimination waged by wealthy nations against indigenous populations. The fact is that war was always horrible news for noncombatants. Even medieval European wars in the age in which this ridiculous doctrine was devised featured sieges of cities, starvation and rape as weapons of war. But during the past 70 years noncombatants have been the majority of the victims of wars, often the vast majority, and often all on one side. The primary thing recent wars have done is slaughter civilians on one side of each war. A war simply is a one-sided slaughter, and not some imaginary enterprise in which "noncombatants are immune from attack." Defining "attack," as mentioned above, to not include any mass murders not "intended" by the murderers won't change this.