We’re just a few days away from the thirteenth anniversary of 9/11. Here are a few of the lessons I’ve learned from the last thirteen or so years of perpetual warfare. I offer them somewhat dogmatically, as a mere laundry list minus examples to illustrate what I’m saying. But I have a feeling that the lessons will ring true enough for many people, and that most readers can supply appropriate examples of their own.

(1) The inevitable gap between normative theorizing and political practice
A war can be justified in principle as a proportionate response to unprovoked aggression, have a rational object, have clear and publicly stated conditions for victory, and still not be worth fighting because there is no guarantee that the war will be fought on the grounds that were publicly given for fighting it. Even if a war seems perfectly justified on every conceivable matter of principle, remember that wars are fought in the real world, not ex hypothesi in thought-experiments, and that every theoretical simplification you make in thinking about a war will be more than matched by some unforeseeable complication that arises in the fog of war. Those complications may well be significant enough to nullify everything else you managed to think of, and destroy the best theoretical case for “going.”

(2) The perpetual opacity of post bellum considerations
It’s always easier to grasp the immediate and supposedly urgent reasons for going to war than to conceive, in detail, of the post bellum conditions that the war is supposed to bring about–much less to predict those conditions. But in confronting any suggestion that “we need to go to war,” try to imagine and predict how things will go in the end game, starting with the best-case scenarios and moving to the worst. I predict that you’ll find it hard even to imagine how to bring about the best-case scenarios (at least in any fine-grained way). The harder you find this, the better the case for not going.

(3) The crudeness of just war theory
The conceptual apparatus that philosophers bring to bear on the conduct of war consists of a set of extremely crude tools for dealing with the actual conduct of warfare. This being so, we face the following dilemma: either we should go to war in the knowledge that our best tools for dealing with it are so pathetically crude, or we should, if possible, avoid going to war in the knowledge that our best tools for dealing with it are that crude. I think it’s obvious that the latter fork provides the better way out of the dilemma.

Some examples of the conceptual crudity of some commonly-invoked ‘principles’:

• The so-called non-initiation of force principle merely tells us that for any x, if x is an instance of force, x ought not to be initiated. It doesn’t give us any indication of the permissible range of values for x, and doesn’t tell us what to do if we face an instance of initiated force.
• The so-called ‘last resort’ principle is, on its own, merely a directive to appeal to war (or ‘force’) as a last resort; it gives no criterion of ‘lastness’ in resorts, and gives no criterion to determine what counts as a ‘use of force’ (often conflating ‘force’ with ‘warfare’ in confusing ways).
• The so-called principle of proportionality appeals to a quasi-mathematical metaphor that is in practice very hard to make literal or apply in any determinate way.
• The so-called principle of discrimination tells us to target combatants but not non-combatants; it doesn’t define ‘combatant’ or ‘non-combatant,” much less apply that distinction to hard cases, or tell us what to do when non-combatants are innocent shields of combatants. Nor does it deal with the obvious but little discussed fact that ex post facto reports of ‘civilian’ fatalities in battlefield conditions are extremely imprecise, and more easily fabricated than reported with accuracy.

(4) The inevitable unreliability of allies, both moral and strategic
Either you go to war alone or you go with a coalition. If you go alone, you fight the war isolated from the rest of the world, so that your adversary can count on active or passive allies throughout the world. If you go with a coalition, the problem becomes that you can’t control what your coalition partners do, no matter how insane or immoral they turn out to be. To this day, it’s unclear whether we should have allied as closely as we did with the Soviet Union during World War II; it’s also unclear whether we should have allied so closely with right-wing dictatorships during the Cold War to fight the Soviet Union, Communist China, and their proxies. The same unclarity extends to the alliances we’ve more recently formed to fight Islamist terrorism.

(5) The inadvisability of ‘reconstructing’ another country, whether for your good, theirs, or both
A country that still suffers race riots over its own legacy of slavery and racial discrimination probably can’t be relied on to reconstruct other countries that suffer from their problematic historical legacies—especially when those engaged in reconstruction are hated as imperialist interlopers, don’t know the history of the countries they’re reconstructing, lack the resources to engage in reconstruction, are confined for security reasons to well-fortified barracks, don’t speak the native language, and are politically hostage to a public back home that is totally uninterested in what they’re doing. It tends not to help that the problematic legacies of countries that are candidates for ‘reconstruction’ arise in large part from ill-conceived prior attempts at reconstruction produced by centuries of imperialism.

(6) Truth as the first casualty of war
Truth really is the first casualty of war, in large ways as well as small. Once war begins, wait for the lies and half-truths to proliferate—from all sides, about all things. And don’t assume that you’ll have the luxury of sifting truth from falsehood during wartime, either. The informational imperatives of wartime are simplicity, digestibility, and coherence with one’s own war effort. If reality doesn’t fit that template, reality will be sacrificed to wartime imperatives, and it will be decades (if that) before anything like a more rational or objective equilibrium is restored. (If you’re interested in ‘getting involved’ in the efforts behind a genuinely justified war, ditch the idea of a military draft or compulsory national service and try an anti-rumor campaign: induce people to stop believing rumors, to stop spreading them, and to criticize any rumors that come their way. You’d be amazed how much harm is done by rumors, and how hard it is to counteract them.)

Incidentally, one casualty of war on the side of those who don’t want war is truth about the nature of foreign aggression. Dogmatic pacifists have a problematic tendency to pretend that foreign aggressors either don’t exist, or are not really aggressing because they’re responding to legitimate grievances. That attitude is too obviously false to be usefully employed in any successful anti-war effort. So don’t.

(7) Domestic liberty as the next casualty of war
The next casualty of war is domestic liberty, along with the ever-present temptation to declare ongoing states of ‘emergency’ demanding ‘emergency measures’—in part by expanding the scope of the concept of ‘emergency’ to cover anything and everything, at whim. Try coming up with a serviceable definition of “emergency,” and try to stick with it.

(8) Civil defense as an alternative to war
If you really want to avoid being attacked by foreign aggressors, seriously consider the possibility of coming up with a civil defense policy that (a) blunts the force of any aggression, (b) costs fewer lives than a war would, (c) gets the whole population involved in the “war” effort, but (d) doesn’t sacrifice domestic liberty in the process. A tall but not necessarily impossible order–no more impossible than the proverbial war that leads smoothly to victory. Your civil defense policy will inevitably have to apply at the borders of your country and be integrated with your border/immigration policy. If you confront dogmatists who insist on ‘open borders,’ ask them whether open borders as they conceive of them require a nation to allow foreign aggressors into the country without challenge. Then ask them how respect for rights would be served by such a policy.

(9) Speak up, speak out
If you oppose the idea of going to war on a given occasion, say so–a lot, to everyone, including your political representatives. People may well regard you as a monomaniac, but in this case, that’s a good thing. Better a monomaniac than a cipher.

A proviso: if you’re going to speak out against war, try not to trespass, vandalize, assault people, or blow things up in the process. It makes you look stupid and hypocritical, and it won’t stop the war.

(10) Patriotism
If you regrettably find yourself in a war, don’t bother to show your patriotic spirit by flying a flag or putting some stupid, bellicose bumper sticker on your car. Find a support organization for injured or debilitated veterans, and support it—financially or otherwise. Nothing clarifies the nature of warfare more powerfully than time spent with combat veterans. And nothing makes it clearer that even the ‘best’ wars are an enormous waste of lives, limbs, blood, effort, time, materiel, and money. If saying that doesn’t count as ‘patriotism’ where you live, say it anyway. Or find somewhere else to live.

A bonus meta-lesson: It’s perfectly OK to come up with outright excuses for not going to war, as long as the excuses don’t obscure the need to go to war in the rare case when war is justified.

The consideration to bear in mind was once nicely articulated to me by a paramedic I met in a medical emergency (I was the emergency): “Look,” he said when I asked him not to move me, “I have to move you. If I don’t move you, things are going to suck. If I move you, I realize: things are going to suck. Basically, no matter what happens, things are going to suck. But they’ll definitely suck more if I do nothing than if I move you. So I have to move you, OK?” He was absolutely right, and after he moved me, put me in a contraption to get me down the stairs, loaded me into the ambulance, and got me to the ER, I managed to get some painkillers into my system–whereupon I agreed with him 100%.

I’m not a pacifist, so my point is not that we should never go to war. It’s that when we do, we should be able to articulate the reasons why in just the way that my paramedic did. It rarely happens. But if volunteer paramedics can do it, so can armchair generals. Something to remember for the next 9/11.

Postscript 1, September 10, 2014: As if on cue, here’s a glimpse into the level of argumentation prevailing among hawkish Republican politicians:

Mr. Cheney, who was among the chief proponents of President George W. Bush’s decision to invade Iraq based on the flawed assumption that Saddam Hussein was harboring weapons of mass destruction and was tied to the Sept. 11 attacks, might have seemed an unlikely messenger of the moment.

But Republicans, for the most part, embraced him anew.

“We can argue over whatever about the Iraq war, but most of our guys believe Bush left in 2009 with the U.S. in position to win” the conflict, Representative Tom Cole, Republican of Oklahoma, said after the session. Mr. Cole added that six years into the presidency of Barack Obama, “at some point, it can’t be Bush and Cheney’s fault.”

Mr. Cheney’s brief talk during a closed-door meeting of the House Republican conference was mostly about the need for Republicans to push to maintain a strong military, but he also argued that his party needed to stop the establishment of a terrorist state in the Middle East.

He did not discuss the fact that many ISIS leaders were former Iraqi military officers who were imprisoned by American troops, nor did he dwell on the sectarian divisions and bloodletting since the 2003 American invasion. The crux of his argument, in fact, centered not on Mr. Obama, but on the isolationist voices on the rise in his party ahead of the 2016 presidential campaign, Republican lawmakers said.

“We can argue over whatever about the Iraq war, but most of our guys believe Bush left in 2009 in position to win.” There’s intellectual leadership for you. A sub-headline to today’s lead story: “Beheadings are Said to Push U.S. to Act–Speech Tonight.” Two war correspondents were beheaded in a war zone–so we have to go to war. If only I were making it up. Perhaps I should revise (6) to say: “Intelligence as the first casualty of war.” And the last.

Postscript 2, September 10, 2014, 8:25 pm: Read this before you buy the President’s argument tonight that he has the authority to order air strikes on Syria–and before you let your Congressional representatives shirk their responsibility to call a vote and make a public decision over it.

Postscript 3, September 11, 2014: From “Struggling to Gauge ISIS Threat, Even as US Prepares to Act“:

Daniel Benjamin, who served as the State Department’s top counterterrorism adviser during Mr. Obama’s first term, said the public discussion about the ISIS threat has been a “farce,” with “members of the cabinet and top military officers all over the place describing the threat in lurid terms that are not justified.”

“It’s hard to imagine a better indication of the ability of elected officials and TV talking heads to spin the public into a panic, with claims that the nation is honeycombed with sleeper cells, that operatives are streaming across the border into Texas or that the group will soon be spraying Ebola virus on mass transit systems — all on the basis of no corroborated information,” said Mr. Benjamin, who is now a scholar at Dartmouth College.

Mr. Obama has spent years urging caution about the perils of wading into the Syrian civil war, a position that has led critics to argue that his inaction has contributed to the death and chaos there. Now, he faces criticism that he has become caught up in a rush to war with no clear vision for how the fighting will end.